Explaining Mental Privacy

The privacy of the mind is generally treated as a platitude, but it is seldom (if ever) asked what explains this platitude. Privacy here is best understood perceptually: states of mind are not perceptible by means of the senses. It is not denied that they may be subjects of legitimate inference, or even of interpretative seeing, but they are not objects of perception in the way the body is. I can see your facial features in a way I can’t see your thoughts or feelings or sensations.[1] These are hidden from me, directly accessible only to you. If consciousness is a stream, it is an invisible stream. The senses are defeated by the mind; the two do not work well together. But why is this the case? What accounts for the invisibility of the mind?

First, let us develop a more articulate sense of the problem of privacy. Is the privacy of the mental a necessary truth? It is not an epistemic necessity: it could have turned out that the mind is not private. Picture the child’s inchoate understanding of the mind: it is by no means self-evident to her that the experiences she enjoys are perceptually inaccessible to others. She might be brainwashed into believing that others can see her thoughts (as we are brainwashed into believing that God can see them), and nothing in her understanding would enable her to rule out the truth of this proposition. It is not analytic or a priori that mental states are private. Nothing about how they appear to the child can logically exclude the possibility of perceptibility by others. This is something she must empirically discover. And likewise we adults cannot be certain that our minds are private—the claim is subject to Cartesian skepticism. I believe my mind is hidden from others, but perhaps I am wrong—perhaps I am surrounded by demigods that can literally see into my thoughts. I can’t be wrong that I have thoughts (the Cogito), but I may be wrong about their privacy: “I think, therefore something about me is invisible” is not a logical certainty.

So is the privacy point a contingent truth? It might not be, since epistemic contingency doesn’t entail metaphysical contingency, but for all we have said it might be. It might be that our senses, as they are actually constituted, don’t reveal other minds but that they could be altered in such a way as to overcome that limitation—or the senses of other beings might not be so limited. Or it may be that minds are necessarily inaccessible to our type of senses: nothing like vision, say, could ever reveal the mind of another—though some hard-to-imagine sense might not be so limited. The question is difficult, and it is compounded by an obvious fact: the mind is perceptible to its owner. I am aware of what I think and feel, though you are not. But then there is nothing about the mind itself that logically precludes perception of it; and if so, what obstacle is there to another subject having a similar kind of access? Couldn’t someone else have quasi-introspective access to my mind? It would be wrong to dismiss this point by insisting that introspection isn’t strictly a sense, so that its existence cannot be a reason to allow for a similar sense in others; for that would be equivalent to arguing that we can rule out the inner sense theory of introspection simply by observing that mental states are private. That would be an unconvincing argument, since privacy and the inner sense theory seem perfectly compatible—and indeed that theory has a lot to be said for it. So it is not at all obvious that privacy is a metaphysical necessity: there might well be possible worlds in which minds are perceptually accessible to others. Couldn’t there be reliable causal connections between states of mind and states of observers’ perceptual systems of such a kind that perceptions of the former by the latter were commonplace? Couldn’t there be possible beings that can see into the minds of others? At any rate, I will remain agnostic on the question here, since my question concerns the explanation of the privacy to which we are actually subject. Evidently this is an epistemic contingency, so it should be possible to explain why it holds. What, then, makes it the case that, in our world, minds are invisible?

It is important to appreciate how surprising this privacy really is, despite its familiarity. Not only is it not an a priori certainty; it runs counter to everything we know about the empirical world. It is hugely anomalous, quite bizarre, and very difficult to square with our general scientific picture of reality. Consider the matter biologically. Organisms have evolved a variety of traits useful to their survival. The visible body is the locus of those traits—a collection of functional organs than can be scrutinized with the naked eye (as well as under a microscope). Everything is open to view, public and perceptible. Well, almost everything, because among these evolved traits we have traits of mind—and these are private and imperceptible. This is true for us humans as well as for relatively simple organisms (it is not that the mental traits of reptiles are visible while mammals have evolved private mental traits). Why is this, and how is it possible? What is the point of evolving private mental traits—what does the privacy do for an organism in the way of survival? And how do the genes manufacture such traits? How is invisibility genetically coded? How does the nervous system, itself public and perceptible, generate inner mental states that resist observation? How does the private emerge from the public, both in phylogenesis and in ontogenesis? One would think that all the biological traits of organisms would be alike—all publicly visible—but some are the exact opposite. This cries out for explanation. What is the biological function of privacy, if any? What is it about the mind and the senses that renders the latter unsuitable for perceiving the former? What is the natural ground of privacy?

A first thought would be that it is in the very nature of the mind to be private: that is, we can derive privacy from other constitutive characteristics of mind. Thus we might consider whether intentionality or subjectivity or rationality lies behind privacy—is it because of the former that the latter holds? But this project is quickly dashed: privacy is a logically independent characteristic of mind. Nothing about those other properties of mind entails that mental states should be invisible. So there is no recognized intrinsic aspect of the mind that explains its privacy—nothing in our ordinary conception of it. In particular, nothing about consciousness as such (that we know of) leads inexorably to privacy; the mind could have been public and still had those other characteristics, so far as we can see.[2] Privacy is an add-on, a further trait of mind—as they are add-ons to each other. It begins to seem gratuitous that the mind should insist on invisibility—it lacks a clear rationale. Can we do better?

What about the power of deception? Organisms don’t always want their inner thoughts and intentions to be transparent, so there is survival value in keeping them hidden. Is this the reason the genes ensure that minds remain imperceptible? Hardly: the deception motive would only apply to a limited class of mental states; it wouldn’t apply to many organisms whose mental states are as private as those of professional deceivers; and there are also advantages to possessing public mental states, particularly where ease of communication is concerned.[3] So adaptive deception is not the ground of mental privacy. Nor are the usual physical explanations for invisibility applicable to the mind: optical transparency, camouflage, occlusion, size, speed, and glare. These factors can all result in a physical object being invisible, but they don’t apply to the mind. The mind is not a piece of glass or blends in with the environment or sits behind something or is too tiny or moves too quickly or gives off too much light.[4] And it is not as if it wears a magical cloak of invisibility that it can throw off to reveal its fleshly attributes. Its invisibility is more principled, more inherent. Or perhaps we should say that the limitations of perception with respect to the mind are more inherent to it. But this is puzzling for two reasons: first, mental states are inwardly perceptible, so it is not in their nature to resist all perceptual incursions; second, they have causal powers and exist in the natural world (unlike numbers), so there is no reason why they should preclude the evolution of a sense that can resonate to them.[5] In any case, we have not yet found a convincing explanation for such invisibility as we actually find.

An extravagant thought suggests itself: the reason the mind is invisible is that it is immaterial. We can only perceive material things in space, not immaterial things outside of space. So privacy entails dualism. We can deduce from the invisibility of the mind that the mind is not the body and is not dependent on it. There are a host of problems with this line of thought, which I won’t enumerate; let me make two quick points. The first is that it is not clear that immateriality entails invisibility (even assuming we know what “immateriality” means)—are angels and ghosts logically impossible? Is it our belief in immateriality that explains our commitment to privacy? Second, minds are not imperceptible tout court, since they are objects of introspection; and presumably this is compatible with dualism. Immateriality doesn’t preclude this kind of perception—so why the other kinds? Minds may be imperceptible in their very nature, but it is not because their nature is to be immaterial (whatever that might mean). Nor, to my knowledge, has any dualist attempted to prove that doctrine from the fact of privacy (Descartes was much too astute for that).

A more promising line of thought is that we are formulating the problem wrongly: we are presupposing that visibility is the norm and then fretting over why the mind doesn’t conform to the norm, but in fact, it is the other way about. Actually things are naturally invisible and what needs an explanation is why anything should be detectable by the senses. The question should be why the body is perceptually accessible. There is nothing surprising about the mind not being perceptible, since that is the default condition of the universe; what is surprising is local pockets of perceptibility—and even there the perceptibility may be glancing and superficial.[6] We can imagine a version of Kantian idealism behind this view, or reflections on current physics and “dark matter”. The thought is that reality is inherently removed from our senses and what we say we see is just our own mode of representing it—sense data, mental constructions, subjective phantasms. Then it is simply par for the course that minds are not perceptible—since nothing is! Reality is inherently not set up for the senses, or the senses are not set up for it.

This is a gratifyingly extreme position, but it won’t help us in the present connection, whatever may be said for it generally. For again, the fact is that mental states are perceptually available—to introspection. They are not naturally cut off from our epistemic faculties, like the most hidden of invisible particles or the constituents of dark matter—or even fields and forces. They are very proximate to us from an epistemic point of view. This is what is so puzzling about their third-person privacy: it is not that they are necessarily hidden to others as such that creates the puzzle but that they are selectively hidden. Why is that things that are so transparent from one point of view are so opaque from another?[7] This approaches the status of paradox, unlike generally hidden facets of the universe: so known and yet so unknown. It is as if God gave us one faculty with which to survey mental reality but refused to give us any more—introspection but not vision or hearing or touch or smell or taste. Mental states exist for the apprehension thereof, but the apprehension must only be from a single standpoint. Why not make the mind either universally unperceived or universally perceived? Why make us so acute in one way but so blind in another—and with respect to the very same objects?[8] Those who contend that reality at large eludes perception generally accept that the mind itself is open to immediate inspection—though they are insufficiently puzzled about its selective openness. We make no progress with our question by asserting that reality is generally cut off from our cognitive faculties, because that is signally not the case with the mind. Our explanandum is not that the mind is invisible tout court but that it is invisible to others while visible to oneself; or, as we might say, the fact that something as familiar as the mind is so removed from the world of the senses. One would think that it ought to be perfectly open to perception by others. Everything seems to point in that direction—introspection, biology, the general nature of reality—but for some reason, the mind refuses to yield itself up to the senses.[9]

Is it that the raw materials of mind are themselves imperceptible, so that evolution has no choice but to render the mind imperceptible? A panpsychist might contend that the proto-mental aspects of reality that form the basis of the mind are by nature imperceptible entities, more so than atoms and the like. So there is really no alternative to invisible minds—the properties of the parts transmit themselves to the whole. But this proposal also faces fatal objections. First, it can’t explain introspection: those primitive parts have to be capable of composing inwardly perceptible mental states–but how? Second, they raise the same question: why are they so radically imperceptible? Why does reality consist of both public and private objects? Could there be a sense that brought the proto-mental within its sights? The entities exist in nature, possess causal powers, and are aspects of public objects—and yet they are not perceptible, perhaps necessarily so. It is a puzzle; even a paradox, once we acknowledge introspection. Maybe there is an answer to the puzzle, but we have not yet found it.

What if the respiratory processes of the body were visible while the digestive processes were not? That would seem very odd. But why are the processes we designate as “mental” invisible while the rest are visible? Both are evolved biological traits arising from the same mechanisms and basic materials, so why the dramatic distinction? Suppose we were visited by aliens equipped with minds and senses that enable them to perceive each other’s mental states (perhaps ours too); to them, the idea of mental privacy would seem bizarre. They are surprised to learn that we are mentally blind (as they unkindly put it) and their philosopher-scientists get to work to explain this oddity in our makeup. To them there is nothing natural or inevitable about it, theoretically or practically; they read minds as they read texts. They have perceptual experiences of others being in pain and they think nothing of it. They think we are biological anomalies—they have seen nothing like us despite their extensive inter-galactic travels. Do we have some strange genetic defect? They refer to Earth as “the planet of the blind”, meaning mentally blind. They offer to engineer our deficit away, and are prepared to accept reasonable trading terms for this service (dancing lessons, massages). We accept their offer and wake up after the operation with vivid perceptions of other people’s states of mind—the phenomenology is extraordinary! You don’t feel other people’s pain exactly, but boy do you get a strong sense of it—nothing like that old insipid behavior-based belief that someone else is hurting. Your empathy really shoots up. You find yourself living in a whole new world. I am trying with this story to make strange the predicament in which we actually find ourselves: powerfully conscious of our own mind but only dimly aware of the minds of others. We stare at others and find nothing mental to look at, yet we know that behind the veil lies a mental life as rich as our own. How frustrating it is that we can’t penetrate the veil and observe other minds as they really are! Wouldn’t it be amazing if we could literally see the mental life of a bat? So near and yet so far! And we have no clear idea about why we are thus confined—no explanation of the fact of privacy. Why isn’t the opposite the case—the body is invisible but the mind is visible? Is that beyond God or nature to contrive?

There must be an explanation for privacy, despite its elusiveness, and whatever it is would surely shed considerable light on the nature of consciousness and the mind, as well as on the nature of our knowledge. But we haven’t been able to come up with one, not even an incomplete explanation. It is hard even to get one’s mind around the problem (what would it even be to see into the mind of another?): we have yet another mystery to add to the pile. We don’t know why our minds can’t be seen or heard or touched or smelled or tasted.


[1] I should say a word about those who believe that the mind is perceptible, as when we see a man’s suffering in his face. I don’t accept that type of description at face (!) value, but even if I did it would not affect the point of this paper, since it would be agreed that other minds are not perceivable except by virtue of expressive behavior. No one supposes that you can see the mind of another when there is no behavior to go on, say when the person is asleep and dreaming. The question then would be what explains this fact.

[2] The question is difficult but it doesn’t seem that consciousness itself is the root of privacy, its sine qua non, since the same point applies to the unconscious—it too is invisible.

[3] Would there be any need for speech if the mind were interpersonally transparent? Apparently not, so why isn’t there some selective pressure to evolve transparent minds, thus dispensing with the need for speech? Speech just seems like a rather cumbersome way to get your thoughts across.

[4] Note too that we cannot see the mind under ultraviolet light or take an X-ray of it (this inaccessibility applies equally to brain scanning machines).

[5] We could add that the close involvement of mind and brain also makes it surprising that the mind is invisible, since the brain is not. One would think that the mind would be as perceptible as the brain given their intimate connection. (To those who claim that the mind is perceptible because the mind is the brain, I make the obvious reply: even if it were true that there is de re perception of mental states in those states of the brain with which mental states are identical, it would not follow that the brain states are perceived as mental. That is, brain states do not appear to us as mental states.)

[6] We can easily envisage a form of materialism that accommodates the invisibility of the mental: just identify mental states with states of dark matter!

[7] Even if physical objects are not perceptually accessible, they are at least represented in perception—it seems to us as if we are seeing them. But that is not true of mental states—it does not seem to us that we see them. So there would still be an asymmetry between imperceptible physical objects and imperceptible mental states.

[8] Note that I can be experiencing a pain in my foot while being unable to perceive that very pain in myself: I introspect the pain in all its glory but no matter how hard I stare at my foot or my brain I can see nothing of its throbbing existence. I am perceptually cut off from a fact about myself that I know vividly from the inside. So the problem concerns not just my knowledge of other people’s sensations but also my knowledge of my own sensations.

[9] There is an analogous problem about introspection and the physical world: introspection is limited to the mental world, not extending to physical states of the organism. But why is this—why can’t we introspect our brain states, say? It doesn’t seem logically impossible and yet it never happens. I won’t discuss this problem here, limiting myself to the problem of why perception doesn’t extend to the mind.


What is Belief?



What is Belief?



For all the work that has been done on the topic of belief, do we really know what belief is?[1] What kind of state (if state it be) is the belief state? Two suggestions have been prominent: belief is a feeling and belief is a disposition. Either belief is a state of consciousness analogous to sensation (pain, seeing red, feeling sad) or it is a tendency to behave in a certain way (assenting to a proposition, combining with desire to produce action). The OED defines “believe” as “feel sure that (something) is true”, thus categorizing belief as a type of feeling: not “be sure” but “feelsure”. What that feeling might be is left undetermined, though the definition has the ring of truth. And indeed belief is connected to feeling: your feelings tend to change when you acquire a belief, and there is such a thing as feeling sure. But what about beliefs you hold without thinking about them– are those beliefs all associated with feelings? Do you feel sure that London is in England, for example, even when the thought has not crossed your mind in months? Here is where the dispositional theory suggests itself: belief isn’t an episodic state of consciousness but a readiness to act in a certain way—to respond “yes” when asked whether London is in England, say. Ramsey said belief is a “map by which we steer”, emphasizing that beliefs guide action (but do we inspect our beliefs as we inspect maps?). And certainly beliefs and dispositions are tightly connected (as are desires and dispositions): your dispositions change when you acquire a belief, and belief encourages assent behavior. But is this what a belief is? Isn’t it rather the mental state that gives rise to the disposition? What if you had a tendency to assent verbally to propositions not because you believe them but because you have been rigged up that way by a clever scientist intent on simulating the state of belief? In general, dispositional theories confound properties (states, facts) with their causal consequences; and we want to know what belief is not what it does. The OED also has this under “believe”: “accept the statement (of someone) as true”. But don’t we accept statements because of what we believe? It isn’t that the belief is the acceptance. It is hard to avoid the impression that the dictionary (and the usual philosophical theories) conflates the symptoms of belief—feelings and dispositions–with belief itself. But then what is belief itself exactly?

Are we acquainted with belief itself? We are acquainted with sensations and behavior, both signs of belief, but are we acquainted with beliefs? The answer is not obvious. If we are, it seems curious that we draw a blank when considering the nature of belief; but if we are not, why do we bandy the concept around with such confidence? Is it perhaps that the concept is logically primitive and hence admits of no explanation in other terms? But that can’t be the reason for our ignorance, because the same is true of many concepts and yet we are not blind to the nature of their reference (pain, seeing red, maybe moral goodness). Or is it that the felt ignorance is an illusion born of a mistaken assumption, namely that we only know what a mental phenomenon is if we can reduce it either to a feeling or to a disposition? Maybe we know exactly what belief is but we think we don’t because beliefs are not sensational or behavioral, these being our preferred touchstones of mental reality when thinking philosophically. But that approach, though not unsound in principle, is hard to square with an evident fact: we really don’t know what it is to believe something—we have no conception of what fact is at issue. Once belief is distinguished from its symptoms its elusiveness becomes evident (compare Hume on causation).

This leaves us with another possibility—that “believes” is really a name for an I-know-not-what that we introduce to denote something that we reasonably believe to exist but can’t properly conceptualize. Belief is thus that state, whatever it is, that has such and such symptoms and plays such and such a role but whose nature we find elusive. In short, “belief” is a theoretical term—not just in application to others but also in application to oneself. Our knowledge of belief operates at one remove from the thing itself, which is why we have such an indeterminate conception of it. A similar approach might be suggested for the concepts of meaning and the self: these too are not directly encountered constituents of consciousness, which is why we can’t reconstruct them in such terms, but they are real nonetheless, just at some epistemic distance from our cognitive faculties. That is, not all parts of what we think of as the mind exist at the same epistemic level (and not because of a detached Freudian unconscious); some are not objects of direct inspection (perceptual or introspective). The ontology of folk psychology is an amalgam of these two types of fact (and we can add desire to belief): the mind consists of directly known constituents and relatively unknown constituents. Differently stated, belief (desire, meaning, the self) is a state that we refer to but are not acquainted with; we know many of its properties, but not its intrinsic nature. We know it is a propositional attitude (but what is an attitude exactly?) and that it involves the exercise of concepts, as well as being a truth-bearer, subject to referential opacity, and capable of combining with desire to lead to action: but we don’t grasp what kind of state it is—not in its intrinsic nature. The state gives rise to inner feelings and to outer behavior, but we have no clear idea of what it is in itself. We experience shadows of it, fleeting intimations and glimpses, but we have no firm conception of the thing itself: it is just “that which gives rise to these symptoms”. Ask yourself what kind of mental state you are in when you are asleep: you have various beliefs, but what is their mode of existence exactly? You might be tempted to reach for the concept of a disposition, but we have been down that road before—what is the ground of such a disposition? Let’s face it: you don’t know what to say, and yet you don’t doubt that you are in some sort of mental state. You might sputter that you are in a “cognitive state”, but that raises the same question over again: what kind of state is that? Not a feeling state and not a disposition, but a sui generis state that confounds comprehension. As we might say, we have only a partial grasp of what belief is. And the part we don’t grasp intrigues us the most, i.e. the very being of belief.

I grant that this position might sound counterintuitive. Doesn’t the Cogito express certain knowledge (“I believe, therefore I am”)? But how can that be if we don’t know what thinking (believing) is? However, this is really not such a paradoxical position to be in: we know that we think and believe, and that this entails our existence, but it doesn’t follow that we know what thinking and believing are—or what the self is for that matter. And did Descartes ever claim anything to the contrary—did he suppose that the nature of thinking is totally transparent to us? Knowing that something exists is not the same as knowing its nature. If Descartes had claimed that thinking is processing sentences in the language of thought, he could have been wrong about that; but this wouldn’t undermine the Cogito. In fact, I would say that if you focus really hard on what is going on when you believe something you will see that nothing determinate comes into view—you never catch your belief in flagrante, as it were. And you have no clear conception of what it is that you attribute when you ascribe beliefs to others (beyond their conceptual content). Nor does knowledge of the brain help: identifying belief with neural excitation in the B-fibers, say, affords no knowledge of what belief is in the ordinary sense. The problem is that neither does anything else—crucially, not introspection. We didn’t come by the concept of belief by noticing feelings of belief in ourselves (where would those feelings to be located?), or by observing the operation of dispositions to behavior; rather, we introduced a term for a type of psychological state whose nature was not evident to us but which we were sure existed. I have evidence for my beliefs drawn from my experience (e.g. feelings of conviction), but I don’t believe in beliefs because I can grasp them whole. I see them through a glass darkly. I have a nebulous sense that certain propositions attract my assent, as if gravitationally, but what exactly my mind is up to I cannot tell. Even the strongest of our beliefs, say religious or moral or scientific beliefs, fail to disclose their inner nature—we just find ourselves filled with passionate conviction about certain things. It isn’t like feeling a headache or a hunger pang in the stomach. Nor is it like hearing a sentence in your head. It isn’t like anything.

Psychology used to be conceived as an introspective science, and then later as a science of observable behavior, but these ideas were predicated on a certain conception of the essence of the mind. Either the mind consists of inner episodes of consciousness of which we have immediate introspective awareness, or it consists of outer behavior that can be perceived externally. But the case of belief (also desire) shows that these alternatives are not exhaustive and are fundamentally on the wrong track. In so far as psychology is about belief and kindred states, it is not about feelings or behavioral dispositions, but about facts we find systematically elusive, which fit into neither category. Beliefs are not feelings and they are not dispositions to behavior, yet there are fully mental phenomena, paradigmatically so. As Hume would say, we have no impression of belief, yet belief is real and knowable (in some of its aspects).  Belief is yet another example of the limits of human cognition. Psychology thus has an elusive subject matter.[2]



[1] The background to this essay is scattered. The issues discussed bubble under the surface of Wittgenstein’s Philosophical Investigations and are explicitly posed in Kripke’s Wittgenstein on Rules and Private Language (as well as my Wittgenstein on Meaning). In addition, the emphasis on ignorance reflects my standing interest in human mysteries as they pertain to philosophy. Hume is hovering paternally in the wings. Russell makes a brief appearance.

[2] It might be said that belief is a computational state and that this gives its essential nature. There is a lot to be said about this suggestion; suffice it to remark that this doesn’t give us a conception of belief comparable to our intuitive notions of pain or seeing red. Belief may well have computational properties, but it is another thing to claim that this is what belief is (would it follow that computers believe?).


Knowledge and Human Nature



Knowledge and Human Nature



An alien observer of human cognitive development would be struck by a fact he might be tempted to describe as paradoxical. This is that in the first five years or so of life development is rapid and impressive while subsequent learning tends to be slow and laborious. The typical five-year-old already has excellent sensory awareness of the world, a mature language, and a fully functioning conceptual scheme—all without apparent effort. They may be small, but they are smart. The reason for this precocity, we conjecture, is that much of what they have achieved by that age is the unfolding of an innate program or set of programs: all this cognitive sophistication is written into the genes awaiting read-out.[1] It is not picked up by diligent inspection of the environment. It comes quickly because it was already present in substantial outline. Thereafter the child must learn things the hard way—by learningthem. Hence school, memorization, studying, instruction, concentration. Knowledge becomes willed, while before it was unwilled, spontaneous, given.[2] Cognitive development turns into work.

It could be otherwise for our alien observers: they are accustomed to school virtually from birth, because their children are born knowing practically nothing. They learn language by painstaking instruction, having no innate grammar; concepts are acquired by something called “deliberate abstraction”, which is arduous and time-consuming; even their senses need years to get honed into something usable. They don’t reach the cognitive level of a typical human five-year-old till the age of fifteen. Empiricism is true of them, and it takes time and effort. However, they have excellent memories and powers of concentration, as well as an aversion to play, so their later cognitive development is rapid and smooth: they are superior to human college-educated humans by the age of seventeen and they go on to spectacular intellectual achievements in later life, vastly outstripping human adults. They are slow at first, given the paucity of their innate endowments, but quick later, while humans are quick at first but slow later (our memory is weak and our powers of concentration lamentable). To the alien observers this seems strange, almost paradoxical: why start so promisingly and then lapse into mediocrity? They continue to gain in intellectual strength while we seem to lose that spark of genius that characterized the first few years of life. That’s just the way the two species are cognitively set up: an initial large genetic boost for us, and a virtual blank slate for them (but excellent capacities of attention, memory, and studiousness). Our five-year-olds outshine theirs, but their adults put ours to shame.

I tell this story to highlight an important point about the human capacity for knowledge—an existential point. The existentialists thought that freedom was the essence of human nature, conditioning many aspects of our lives, individual and social; but a case can be made that human knowledge plays a similar life-determining role. For we suffer under a fundamental ambivalence about knowledge, which is to say about our cognitive nature (which is not confined to non-affective parts of our lives). We are simultaneously very good at knowledge and quite poor at it. Some things come to us naturally and smoothly, especially in our earliest experience (pre-school); but other things tax us terribly, calling for intense effort and leading to inevitable frustration. Rote memory becomes the bane of our lives. Examinations loom over us. School is experienced as a kind of prison. Calculus is hard. History refuses to stick. Geography is boring. What happened to that earlier facility when everything came so easily? We were all equal then, but now we must compete with each other to achieve good test results, which determine later success in life. We seem to go from genius to dunce overnight. Imagine if you could remember your earlier successes and compare them with your current travails: it was all so easy and enjoyable then, as the innate program unfurled itself, but now the daily need to absorb new material has become trial and tribulation. Getting an education is no cakewalk. Wouldn’t it be nice if it could just be uploaded into your brain as you slept, as your genes uploaded all that innate information? It’s like a lost paradise, a heavenly pre-existence (shades of Plato), with school as the fall from blessedness. You are condemned to feel unintelligent, a disappointment, an intellectual hack. Maybe you will make your mark in society by dint of great effort and a bit of luck, but you are still a member of a species that has to struggle for knowledge, for which knowledge is elusive and hard-won. Suppose you had to live in a society in which those late-developing aliens also lived: they would make you look like a complete ignoramus, an utter nincompoop—despite their initial slow start.

A vice to which human beings are particularly prone is overestimating their claims to knowledge. It is as if they need to do this—it serves some psychic purpose. Reversion to childhood would be one hypothesis (“epistemic regression”). But the actual state of human knowledge renders it intelligible: within each of us there exists a substantial core of inherited solid knowledge combined with laboriously acquired knowledge, some of it shaky at best. Take our knowledge of language, including the conceptual scheme that goes with it: we are right to feel confident that we have this under control—the skeptic will not meet fertile ground here (I know how to speak grammatically!). Generalizing, we may come to the conclusion that our epistemic skills are well up to par: so far as knowledge is concerned, we are a credit to our species. But this is a bad induction: some of our knowledge is indeed rock solid, but a lot isn’t. Being good at language is not being good at politics or medicine or metaphysics or morals. We are extrapolating from an unrepresentative sample. As young children, our knowledge tends to be well founded, because restricted to certain areas; but as adults we venture into areas in which we have little inborn expertise, and here we are prone to error, sometimes fantastically so. We know what sentences are grammatical but not what political system is best. But we overestimate our cognitive powers because some of them are exemplary. It would be different if all our so-called knowledge were shaky from the start; then we might have the requisite humility. But our early-life knowledge gives us a false sense of security, which we tend to overgeneralize. We believe we are as clever about everything as we are about some things.

I recommend accepting that we have two sorts of knowledge—that we are split epistemic beings. On the one hand, we have the robust innately given type of knowledge; but on the other hand, we have a rather rickety set of aptitudes that we press into service in order to extend our innately given knowledge. Science and philosophy belong to the latter system. Thus they developed late in human evolution, are superfluous to survival, and are grafted on by main force not biological patrimony. There is no established name for this distinction between types of knowledge, though it seems real enough, and I can’t think of anything that really captures what we need; still, it is a distinction that corresponds to an important dimension of human life—an existential fact. We are caught between an image of ourselves as epistemic experts and a contrasting image of epistemic amateurishness. We are not cognitively unified. We have a dual nature. We are rich and poor, advantaged and disadvantaged. Other animals don’t suffer from this kind of divide: they don’t strive to extend their knowledge beyond what comes naturally to them. Many learn, but they don’t go to school to do it. They don’t get grades and flunk exams and read books. Reading is in some ways the quintessential human activity—an artificial way to cram your brain with information not given at birth or vouchsafed by personal experience. Reading is hard, unnatural, and an effort. It is an exercise in concentration management. We may come to find it enjoyable[3], but no one thinks it is a skill acquired without training and dedication (and reading came late in the human story). It is also fallible. And it hurts your eyes. This is your secondary epistemic system in operation (we could label the types of knowledge “primary knowledge” and “secondary knowledge” just to have handy names).

Animals are not divided beings in this way (lamenting their reading ability); nor do they apprehend themselves as so divided. But we are well aware of our dual nature, and we chafe at it (as the existentialists say that we chafe at the recognition of our freedom). We wish we could return to epistemic Eden, when knowledge came so readily; but we are condemned to conscious ignorance, with little inroads here and there—we are aware of our epistemic limits and foibles. We know how much we don’t know and how hard it would be to know it (think of remote parts of space). We know, that is, that we fall short of an ideal. We can’t even remember names and telephone numbers!  Yet our knowledge of convoluted grammatical constructions is effortless. If we are that good at knowledge, why are we so bad? Skepticism is just the extreme expression of what we all know in our hearts—that we leave a lot to be desired from an epistemic point of view.[4] We are both paragons and pariahs in the epistemic marketplace. In some moods we celebrate our epistemic achievements, in others we rue our epistemic failures. The reason is that we are genuinely split, cognitively schizoid. Perhaps in the prehistoric world the split was not so evident, in those halcyon hunter-gatherer days, before school, writing, and transmissible civilization; but modern humans, living in large organized groups, developing unnatural specialized skills, have the split before their eyes every day—the specter of the not-known. We thus experience epistemic insecurity, epistemic neurosis, and epistemic anxiety. Our self-worth is bound up with knowledge (“erudite” is not a pejorative). It is as if we contain an epistemic god (already manifest by age 5) existing side by side with an epistemic savage: the high and the low, the ideal and the flawed. I don’t mean that we shouldn’t value what we acquire with the secondary system, or that it isn’t really knowledge, just that it contrasts sharply with the primary system. The secondary system might never have existed, in which case no felt disparity would have existed; but with us as we are now we cannot avoid the pang of awareness that our efforts at knowledge are halting and frequently feeble. The young child does not suffer from epistemic angst, but the adult has epistemic angst as a permanent companion. School is the primary purveyor of that angst today. Education is thus a fraught venture, psychologically speaking, in which our dual nature uneasily plays itself out. The existentialists stressed the agony of decision, but there is also the agony of ignorance (Hamlet is all about this subject, as is Othello).[5]

Freud contended that the foundations of psychic life are laid down in the first few years of life (and sex not freedom or knowledge is the dominant theme), shaping everything that comes later. The stage was set and then the drama played out. I am suggesting something similar: the first few years of cognitive life lay down the foundations, and they are relatively trouble-free. Knowledge grows in the child quite naturally and spontaneously without any strenuous effort or difficulty. Only subsequently does the acquisition of knowledge become a labor, calling upon will power and explicit instruction. We might view this transition, psychoanalytically, as a kind of trauma: from ease to unease, from self-confidence to self-doubt. Whoever thought knowledge could be so hard! Compare acquiring a first language with learning a second language: so effortless the first time, so demanding the second. What happened? Now learning has become a chore and a trial. It is a type of fall from grace. The reason we don’t feel the trauma more is that it happens at such an early age (I assume there is no active repression)—though many a child remembers the misery of school. Knowledge becomes fraught, a site of potential distress. Cramming becomes a way of life, a series of tests and trials. But all the while the memory of a happier time haunts us, when knowledge came as easily as the dawn.[6] And then there is death, when all that knowledge comes to nothing—when all the epistemic effort is shown futile. Our divided nature as epistemic beings thus has its significance for how we live in and experience the world. It is not just a matter of bloodless ratiocination.



[1] I won’t rehearse all the evidence and arguments that have been convincingly given for this conjecture, save to mention the existence of critical periods for learning. Would that such periods could occur during high school mathematics training!

[2] Of course, we still pick up a lot of information without effort just by being in the world, but for many areas of knowledge something like school is required (this is true even for illiterate tribes).

[3] Logan Pearsall Smith: “People say that life is the thing, but I prefer reading.”

[4] Is it an accident that one of the prime distinguishing characteristics of God is his omniscience? He knows automatically what we can never hope to.

[5] The Internet, with its seemingly infinite resources, drives this point home. It also leads to varied and grotesque deformities in our cognitive lives.

[6] Here you see me lapsing into weak poetry, as all theorists of the meaning of life must inevitably do. Sartre’s Being and Nothingness is one long dramatic poem: who can forget his puppet-like waiter, or the woman in bad faith whose hand remains limp as her would-be suitor grasps it, or Pierre’s vivid absence from the cafe? My illustrative vignette would feature a bleary-eyed student studying in a gloomy library while recollecting her carefree sunlit days of cheerful effortless knowing.


Are There Subjective Concepts?

I can imagine four types of position on this question: (i) there are only subjective concepts (none are objective); (ii) there are only objective concepts (none are subjective); (iii) there are both subjective concepts and objective concepts; (iv) all concepts are both subjective and objective (in some respects). I am inclined to accept (iv), with (ii) as my second favorite, so I reject some standard views on this subject. Obviously the question turns on what is meant by “subjective” and “objective” in this connection. If we mean, “contributed by the mind and not by the world” by “subjective”, and “contributed by the world and not the mind” by “objective”, then the position I favor is that all concepts are partly a function of the mind and partly a function of the world. That is, our cognitive makeup partly fixes the nature of our concepts, but part is also fixed by reality, as it exists outside the mind. But I am not primarily interested in arguing for this position here; I want to discuss a more limited question–namely, is it possible for there to be both a subjective and an objective concept of the same state of affairs? Can we view (represent, describe, cognize) a single fact in two different conceptual ways, subjectively and objectively? To adopt a well-known locution, is it possible to conceive of a single property both from a particular “point of view” and also from no point of view (from “nowhere”)? Could we start by conceiving a property (fact, state of affairs) subjectively and then develop an objective way of conceiving it? Could we (do we ever) “transcend” a subjective concept and replace it with an objective concept, or simply retain both concepts? Granted, it is perfectly possible to conceive of the same property (object, kind) using two different concepts, but is it ever the case that one of these concepts is subjective and the other objective?[1]

We can accept that there are subjective and objective states or properties or facts, if by that we mean states of subjects and states of objects. Pain is a subjective state because it is a state of conscious subjects, but electric charge is a state of an object that is not a conscious subject (generally). But what about the concepts of such subjective states—are they too subjective? It is not immediately clear what this might mean, but the most obvious interpretation is that the concept of pain can be possessed only by someone who feels pain—you can only know what pain is if you have experienced it. So the concept is subject-relative: there are preconditions for possessing it that require a certain psychological makeup. There are two points to be made about this. The first is that it is not clear why this condition justifies the term “subjective”: isn’t it just a claim about the necessary conditions for possessing the concept? Why should the condition imply that the concept of pain embodies a subjective view of pain? Why not say that the concept is completely objective about pain, even though it can be acquired only by experiencing pain? Why should it imply that pain could be more objectively viewed in some other way? If the concept reveals the nature of pain as it is in itself, why is it described as “subjective”? Isn’t it entirely objective–certainly not limited or defective or biased in some way? Second, isn’t an analogous proposition true of any concept? Any concept, no matter how objective, can only be grasped by beings psychologically equipped to grasp it—isn’t that a tautology? You can only grasp the concept of electric charge if you have a certain cognitive makeup, perhaps involving language with its specific architecture (animals don’t grasp it). So that concept is also subjective-relative: it requires a certain kind of mind, a certain cognitive “point of view”. No concept can be possessed by a vacuum! The notion of an objective concept had better not require that there is no kind of mind-dependence. There are sensory “points of view” and cognitive “points of view”, and concepts can be possessed only by beings that bring those points of view to the table. So far we have found no meaningful distinction between so-called subjective concepts and objective concepts. True, the concept of electric charge doesn’t require any specific sensory apparatus to be possessed; but it is equally true that the concept of pain doesn’t require any specific cognitive apparatus to be possessed, such as that required for the understanding of physics.

Consider color: we can agree that color is a subjective phenomenon since it depends on the existence of sensory appearances, but why say that our ordinary concept of color is subjective? That certainly doesn’t follow from the subjectivity of color itself—the concept might be entirely objective. Indeed, I would defend the view that our ordinary concept of color represents color just as it intrinsically is—just as it objectively is—and that it cannot be improved upon by moving in a more objective direction. There is no such thing as an objective conception of color that is distinct from the conception we have by virtue of our experience of color (given that color is a subjective phenomenon). Thinking of color under physical concepts such as wavelength is not a more objective (more accurate) conception of color but rather a mode of thinking appropriate to the physical basis of color (compare pain and C-fiber stimulation). Our concept of red, say, is not one perspective on redness that might be supplemented or superseded by some more objective concept; it tells us what redness actually (objectively) is. So it isn’t that we have a subjective view of color that can be compared with an objective view; we simply have an objective concept of a subjective phenomenon. The fact that we can have this concept only by seeing color ourselves doesn’t entail that the concept itself fails of objectivity or is somehow “subjective”. A concept is a mode of presentation of a property and our ordinary concept of red presents it as it really is, objectively; we don’t render our concepts of color any more objectively penetrating by couching them in physical terms—on the contrary. I would say, then, that our color concepts are not subjective but objective—or better, that they are objective and also subjective in the trivial sense that you can only possess them if you have a certain type of psychological makeup. The nature of color is fully captured in our ordinary concept of color (in our ordinary knowledge of it), and that is what an objective concept is supposed to do (compare the concept of pain). A subjective concept of red might be expressed by “what reminds me of my true love”—since other people don’t share my romantic associations—but that is a far cry from our ordinary concept of red. I therefore think there is no good sense in which our color concepts are subjective. They are concepts of something subjective, but that doesn’t prove that they themselves are subjective—any more than that the objectivity of a fact implies the objectivity of any conception of it. Indeed, I would venture to assert that anyone who has an adequate concept of red has precisely the concept of red that I have, i.e. the concept that is derived from inner acquaintance with sensations of red. There is no more objective concept of red, and this concept is not subjective in any interesting sense. In fact, the whole idea that concepts contain “perspectives” on their reference is misguided (based on a false perceptual model); certainly our color concepts and concepts of sensations are not to be understood in that way.[2]

It might be thought that theoretical identification affords an illustration of subjective and objective concepts of the same thing. We have discovered that water is H2O and heat is molecular motion: aren’t these cases in which a subjective concept is coupled with an objective concept? The ordinary concepts embed our modes of sensibility while the scientific concepts don’t; the former can only be grasped by beings that share our “point of view”. But these cases repeat what we have already seen: the concepts are really objective concepts of a subjective fact. The subjective fact is the way water and heat appear to us in sensation, and this is incorporated into the concept (“the thing that appears thus and so”). We have a concept of this appearance—a sensory concept—and the appearance is a subjective fact, i.e. a fact about conscious beings: but the concept itself is not a subjective view of an appearance. It is an objective representation of something itself subjective. Anyone who shares the concept accurately and completely grasps the appearance in question; and the appearance can’t be grasped properly unless that concept is possessed. It is not that the scientific concept is another way to grasp that appearance, which is somehow more objective; it is a concept of a physical thing not of a mind-dependent mode of appearance.[3] Maybe it is true that you can only grasp the concept of that appearance by being subject to it, but why should this imply that the concept inherently involves a subjective way of apprehending what it represents? The concept denotes the appearance “directly”, just it is objectively is; it is not a subject-dependent “perspective” on its referent. It is not that in these cases we have two types of conceptualization of the very same fact or property, subjective and objective; rather, we have concepts of water and heat, the physical things, coupled with concepts of other facts, facts of appearance. The latter concepts are just as objective as the former, since they capture the objective nature of the appearance (which is a subjective fact). To repeat, concepts of the subjective are not thereby subjective concepts—just as concepts of the objective are not thereby objective concepts (“the metal I love best”). There is no coherent sense in which one’s concepts of one’s subjective states embed a subjective perspective on one’s subjective states—a “point of view” on them that might reveal more about the subject than about them.  Of course, any concept embeds something about the constitution of the conceiver, since it must be conditioned by a given cognitive structure; but that just gives us the trivial truth that all concepts have a “subjective” dimension as well as an objective one. The paradigm of a subjective way of thinking is one in which a person lets emotion interfere with reason (“Do try to be more objective and not let your emotions run away with you!”), but our ordinary concepts of subjective states are nothing like that—they don’t let emotion affect how they represent the mind.

The correct conclusion, then, is that all concepts are objective: they represent things as they objectively are (except when they don’t, as when we pick something out by reference to our personal idiosyncrasies, e.g. “my favorite metal”, “the color I most dislike”). The ordinary concepts of color or sensation or emotion are objective concepts because they pick out what they do in virtue of actual intrinsic properties of the things in question, not by virtue of accidental relations to the conceiver’s peculiarities. It isn’t that philosophical reflection has discovered that concepts we thought were objective turn out to be merely subjective. Common sense concepts are not subjective in some way that contrasts with the concepts of science. True, we perceive the world in ways conditioned by our given modes of sensibility, which are not necessarily shared by all sentient beings, but from this it doesn’t follow that any of our concepts are themselves subjective.


[1] The obvious reference here is to Thomas Nagel’s discussion of subjective and objective conceptions in The View From Nowhere (1986), particularly the first two chapters. However, inspection of Nagel’s text reveals (to me) no outright contradiction between what I maintain and what he says—though there certainly seems to be a difference of attitude and terminology. Much the same can be said about my book The Subjective View (1983).

[2] It is possible to have a subjective view of reality, as when one projects one’s subjective states onto reality, perhaps not realizing that this is what one is doing. This is plausibly what happens with color. Thus one arrives at a view of reality that has subjective elements. But none of this implies that concepts of color are subjective concepts, only that one’s perceptual view of reality involves projected subjective states. One’s entire picture of reality could be constructed from such projected subjective states without any concept being itself subjective (except in the sense of being a concept of a subjective state). There is the conceptual analogue of a use-mention confusion lurking here.

[3] None of this is to deny the distinction between the manifest image and the scientific image: it is just that both “images” are objective.


Modal Metaphysics

In Naming and Necessity, Kripke gives a number of examples of essential properties in order to show that not all necessities are a priori or analytic. He is not concerned to develop a general metaphysics of modality, a systematic classification of necessities and possibilities. But that project is a worthwhile one, and relatively unexplored. I shall offer some remarks on it, hoping to show that there is some interesting structure here: there are patterns and generalizations. I won’t re-defend Kripke’s examples (most of which have sources elsewhere) but take them as given; my question is what general picture they promote. Thus I will accept that there are necessities of origin, kind, and composition: a given human being, say, essentially has the parental origin she has; she is essentially of the kind human; and she is essentially composed of certain biological materials (cells, carbon, etc.). No one could be this human being and not have those properties. These are metaphysical necessities concerning individual human beings. I couldn’t have been born to the British royal family or been a dog or be made of glass—though perhaps someone looking like me could have these properties. By contrast, certain properties of human beings are contingent and could easily be lacked without detriment to identity: I could have had a different occupation or lived in a different place or never pole-vaulted. It would still be me, just living a different life. My history is contingent, but my origin, kind, and composition are not.

Well and good: but is there any deeper story to tell? Do we just have a series of examples of essential and contingent properties with nothing to unify them, or might there be something in common to the examples? Is there a principled dualism or just a list of unrelated instances? With respect to essential properties, I think we can accept two important points. The first is that the list we have so far is complete: Kripke didn’t omit an important class of necessary truths. He never claimed completeness, but reflection suggests that he found it—there are no other de re necessities waiting to be recognized.[1] True, we can analyze the relation of origin and detect various necessities of origin (parents, sperm and egg, strands of DNA); and true, we can distinguish necessities of composition that relate to types as well as to tokens (this table is necessarily made of wood, the type, and also necessarily made of this particular piece of wood, a token)); true also, we can distinguish human beings from persons and accordingly raise two different questions about necessities of kind. But there doesn’t seem to be any additional category of de re individual essence that has not been mentioned; our list appears exhaustive (there is surely no necessity regarding bodily organs, for example, since one can be given someone else’s kidney and have an artificial heart implanted).

The second point is that the three categories extracted from Kripke’s text are logically independent of each other: none entails the others. Thus we can’t deduce origin from natural kind or composition from origin. We have three distinct types of necessity here, not reducible one to the other. This is true even if we extend essentialism beyond biological entities, claiming that individual atoms, say, have necessities of origin, kind, and composition: this very hydrogen atom couldn’t have come from anywhere but the big bang (that event) or been an iron atom or be made of anything but quarks.[2] We seem to have run the gamut—that’s about it as far as essence is concerned. Where an object came from, what it is made of, what kind of thing it is—that exhausts its essential nature; everything else is contingent. We might thus declare a triune theory of individual essence—a holy trinity of separable types of necessity. It would have been nice to find a deeper unity, but it turns out that 3 is the magic number—at least it wasn’t 7 or 29! The three essences do seem naturally connected, certainly not opposed to each other, but there is no apparent way to unify them into a single attribute. Hence we can announce the doctrine of Threefold Essence.

It might be supposed that contingency will yield a richer harvest of types. Aren’t there hugely many kinds of contingent property—occupation, location, hobbies, prejudices, talents, acts performed, things owned? Where is the unity here? The class of contingent truths appears to be hopelessly heterogeneous, a mere motley. But I think, perhaps surprisingly, that this is wrong: there is really only one kind of contingent truth! Or better, all kinds of contingent truth have the same unitary basis. Consider states of motion: being at rest or traveling through space. Suppose I am at rest now, sitting quite still: I could have been in motion, pacing around, playing tennis, driving my car. It is entirely contingent what my state of motion is at any given time. The same is true for any physical object: its state of motion is a contingent property of it—it could exist and yet be in a different state of motion. In fact, if you wanted to give a clear and convincing example of a contingent property, you couldn’t do better than to pick motion—motion is the paradigm of the contingent. An object’s motion is not part of its intrinsic nature, what makes it what it is. Intuitively speaking, motion belongs to the career of an object, not its constitution–its behavior not its being. Maybe an object’s potential for motion is written into it, but its actual state of motion is just so much adventitious history—alternative motion is easily imaginable. Even when motion follows strict laws of nature, as with elliptical planetary motion, we can easily conceive it being otherwise: the earth is not what it is in virtue of tracing ellipses around the sun instead of circles. Just as the earth is not necessarily inhabited, so it is not necessarily in elliptical orbit about the sun.[3]

But what about other types of contingent property, say being a philosopher? They are not types of motion. True enough, but notice that motion is involved in their coming to obtain: I became a philosopher by taking a particular path through space, acting in specific ways, moving my hand to write philosophy essays, etc. I came to have the property of being a philosopher by virtue of certain motions (some in my brain). The same thing is true of my more athletic attributes, as well as musical. So I think we can venture this generalization: every contingent property of an object supervenes on motion. Nothing happens but that motion makes it so. The property might not be a state of motion, but its instantiation depends on certain motion properties being instantiated. When I imagine myself not being a philosopher I imagine various motions not having occurred (e.g. moving from Manchester to Oxford in 1972). So what unifies the class of contingent properties is their dependence on motion—which is the paradigm of the contingent. Whenever we conceive of certain properties not holding we conceive of enabling motions not occurring. This is the basis of our sense of contingency. There is really only one kind of contingent truth—the kind that depends on episodes of motion. History is the history of movement, ultimately. Contingency is therefore monistic, tracing back to a fundamental kind of contingency. Necessity comes in three irreducible types, but contingency is always the same. The loose relation between objects and space is the ground of contingency.[4]

Immediately we notice that origin, kind, and composition have nothing to do with motion. They imply nothing about how things move. They are not part of a thing’s dynamic history—what happens to it or what it does. It is a necessary condition of a property being essential to a thing that it not be a motion-dependent property, but it also seems to be sufficient for essence that the property not involve motion. Any truth about an object that does not directly or indirectly relate to its motion is a necessary truth about it. Take color and shape: these are not essential properties, to be sure, and they seem static, but don’t they tacitly involve motion—motion of parts or particles? The shape of an object might be constant for a period of time, but apply appropriate forces and you get movement of parts—hence the shape is contingent, since it can be altered by motion. Color is contingent because it can be changed by the passage of light coming from the object and by the tiny motions of receptors responding to the incoming light. When we imagine shapes and colors being otherwise we imagine certain motions occurring or not occurring. But no change of motion in an object can change it from having the origin it has to having a different origin, and similarly for kind and composition. Properties are essential when and only when they don’t involve motion, and they are contingent when and only when they do.

This is a pleasing generalization, but can things really be that simple? Does the modal structure of the world divide up so neatly?  Consider numbers: motion is not involved in their having the properties they have and all their (intrinsic) properties are essential.[5] The number 2 is essentially a number, is essentially even, is essentially the predecessor of 3, is essentially a divisor of 16, etc. It has no history that could have been otherwise, no movement that we could imagine reversed—no location, job, hobby, or talent. Nothing happens to it and it does nothing. Movement is alien to its being. Thus it is all essence. It is the same with geometrical figures: they participate in no marches or street-crossings and possess no moveable parts. Contingency is accordingly not in their nature. Contingency enters the life of an object only when history comes to visit, but history consists of motions large and small. In other words, contingency feeds on events, and where there are no events there is no contingency. Then all is necessity. A purely platonic world would lack contingency because nothing would happen in it that could have been otherwise. Universals track no paths through space that they might not have tracked. No journey, no contingency.

There is a line of objection to our neat binary picture that one seldom hears urged today, though it is not without precedent, namely that there is no real contingency in the universe. Everything that happens happens by necessity. This is the opposite of the modal skeptic who denies that anything is really necessary (except maybe analytic truths). Suppose determinism is true, so that everything that happens follows from the laws of nature and hence is nomologically necessary. Suppose too that we regard nomological necessity as a form of metaphysical necessity.[6] Then we reach the conclusion that everything must have happened as it actually happened: there are no contingent facts. Granted, there are impressions of contingency, but these turn out to be illusory upon closer analysis—they confuse what is (allegedly) contingent for this object and what might be true of some counterpart object. We are familiar with the idea that what seems contingent for a natural kind is really what is possible for some other natural kind similar to the one in question (e.g. some liquid similar to water might not be H2O but not water itself). Well, according to the metaphysical view we are considering, when it seems to us that an object might have been otherwise in some respect we are really thinking of some other object that might be that way. In fact, all objects simply play out their essential nature in their actions and reactions (Leibniz held a view like this). If so, all facts are necessary facts–we are merely under an illusion of contingency. I don’t say this view is correct, only that it intelligibly has the consequence that necessity is ubiquitous. In effect, it takes motion to be the necessary unfolding of the intrinsic nature of the universe—though we may not be able to grasp the way this unfolding works. Indeed, it can be maintained that only a view like this can render the world intelligible, since pure contingency is unintelligible (it violates the principle of sufficient reason). If reason is built into the universe, it must work by rational principles, but these can only be necessary truths. Motion, in particular, cannot be arbitrary and spontaneous; it must be written into the nature of things. The world may appear to harbor a deep contingency but this is just an appearance—underneath it has a rational order. I had to become a philosopher; it wasn’t just an accident that could have been otherwise. States of motion are essential properties after all.

I mention this metaphysical position for the sake of completeness, not to endorse it. The position that seems right to me is the usual binary one: we have essences and we have accidents. The essences revolve around origin, kind, and composition, while the accidents owe their existence to the nature of motion. We can grant that motion is governed by natural laws that carry their own type of necessity, and hence strong determinism is true, but that doesn’t add up to full metaphysical necessity. We can conceive these laws being otherwise in a way we can’t conceive origin, kind, and composition being otherwise. There are metaphysically possible worlds in which I became a quantity surveyor and was born in Australia (my parents emigrated) but not worlds in which I am a tiger or made of glass or came from an acorn. The basic structure of modal reality is thus a triad of essential properties, on the one hand, and a unified class of motion-dependent contingent properties, on the other. There is nothing more and nothing less.[7]


Colin McGinn

[1] I don’t mean to assert dogmatically that no other necessities will ever be discovered, though that may be true; I mean only that I don’t know of any obvious ones that fail to show up in Kripke’s text.

[2] I won’t discuss whether all natural objects exhibit all three types of essence, animate and inanimate, but I am inclined to think it is true.

[3] As an exercise in astronomical essentialism we can ask what the necessary properties of the earth are. First its origin: it necessarily came from the stuff it actually came from (probably a bunch of celestial dust); second its kind: it is necessarily a planet; third its composition: it is necessarily made from a specific collection of assorted elements. The earth (that object) couldn’t have come from some other source; it couldn’t be an elephant; and it couldn’t be made of jelly. But there might be a planet that looked like earth but had a different origin and composition (and maybe was a living organism).

[4] Events and time are different: a given event couldn’t have occurred at a different time, e.g. WWI occurring in 1963 (though there could have been a similar war at that time). Whether objects can exist at other times is a difficult question: could I have been born in 1940 or 1066?

[5] Isn’t it a contingent property of the number 2 that it is the number of my cats? We can talk that way, but notice that the alleged property is relational not intrinsic; indeed, it is entirely extrinsic to the number. It is not part of the nature of 2 that it numbers my cats—not a truth of arithmetic.

[6] Kripke toys briefly with this idea in Naming and Necessity, p.99.

[7] Modality is more streamlined than we might have supposed, less variegated. God had relatively little to do in creating necessity and contingency compared to creating all the truths. When creating all the possible worlds he followed a few simple precepts. Reality is modally parsimonious.


Are There Subjective Reasons?




Are There Subjective Reasons?



I like coffee and you like tea. This gives me a reason to choose coffee, but it doesn’t give you a reason to make that choice. The reason is relative to me—to my preferences. You would choose tea given the choice.  Thus we might say that reasons of this type—desire-based reasons—are “subjective reasons”: they are relative to the individual subject making the choice. They are not like “objective reasons” that apply to everyone equally, such as (allegedly) moral reasons, which are indifferent to the individual’s personal preferences. Everyone has a moral reason not to murder his neighbor, no matter how much he might prefer him dead—viz. that it would be morally wrong to do it. But some reasons (perhaps most) are subjective in the sense that they don’t generalize: they apply only to individuals with appropriate desires or wishes or tastes or inclinations. They have no rational hold over anyone else. It would be wrong to criticize someone for not acting on them, given their personal preferences. When it comes to matters of taste, the right response is: “It’s all completely subjective”.

But this is mistaken for two reasons. The first is that your preferring tea gives me a reason to offer you tea, while I contentedly stick to coffee: that is, the fact that you have a preference for tea works as a reason applicable to me to act in certain ways in relation to you. You have a certain property—being a tea-fancier—and that gives me a reason to supply you with tea in appropriate circumstances. So that reason applies to everyone equally: it is objective. It is objectively the case that everyone has a reason to give you tea not coffee: there is nothing subjective about that. Second, ifI shared that property I too would have a reason to choose as you do. So we can generalize as follows: everyone is such that if they have a preference for tea they have a reason to choose tea. It is not as if you could have that preference and it still be a question what you have reason to do. It isn’t “up to you” what it is rational to do, a matter of subjective whim. True, you may not actually have the property in question, but it is an entirely objective matter that ifyou do a certain choice is rational. It is an objective property of the property that it requires a certain choice. It functions as an objective reason whenever it is instantiated. There is nothing subjective about the reason once the facts are fixed. The reason may be said to be a conditionalreason, i.e. it depends on instantiating certain properties, but there is nothing “subjective” about it. Salt only dissolves if certain conditions obtain—that doesn’t make it “subjective”. We might call desires “subjective states” because they are psychological properties of conscious subjects, but that doesn’t imply that they provide merely subjective reasons. Whenever a reason applies it always generates objective requirements: on others to act in certain ways, and on anyone who has the property that grounds the reason. There is never any purely subjective (or “agent-relative”) rationality: all rationality is objective (impersonal, absolute, general).

We might compare this to subjective facts. There are no purely subjective facts, i.e. facts that have no objective reality. There are psychological facts about subjects, but these are objective facts in the sense that they exist absolutely, not forsome people and not others. Bat experiences are facts in the objective world (there is no other). They might be knownonly by bats, but their existenceis not relative to bats—they are part of objective reality (not fictions or dreams or projections). To be is to be objective. Not everyone has bat experiences, but they don’t exist only from the perspective of bats (whatever that might mean). In the same way not everyone has a preference for tea, but that preference exists objectively and gives rise to objective reasons for action that apply to anyone. Even a taste shared by no one else, say a fondness for grilled cactus, has its objective reason-giving power: this idiosyncratic individual can expect to be offered grilled cactus at a barbecue, and if anyone else were to acquire the taste they would have every reason to act on it. There are no reasons that apply to an individual in isolation without implications for anyone else. Rationality is never purely personal in this sense.[1]



[1]We might then say that there are two sorts of objective reason for action: the sort that depends on the psychological make-up of the individual and the sort that doesn’t so depend. The former would include personal tastes; the latter would apply to moral reasons (assuming we accept this view of morality). There are not “subjective reasons” and “objective reasons”.


A Problem In Hume


A Problem in Hume




Early in the TreatiseHume sets out to establish what he calls a “general proposition”, namely: “That all our simple ideas in their first appearance are deriv’d from simple impressions, which are correspondent to them, and which they exactly represent” (Book I, Section I, p.52).[1]What kind of proposition is this? It is evidently a causal proposition, to the effect that ideas are caused by impressions, and not vice versa: the word “deriv’d” indicates causality. So Hume’s general proposition concerns a type of mental causation linking impressions and ideas; accordingly, it states a psychological causal law. It is not like a mathematical generalization that expresses mere “relations of ideas”, so it is not known a priori. As if to confirm this interpretation of his meaning, Hume goes on to say:  “The constant conjunction of our resembling perceptions [impressions and ideas], is a convincing proof, that the one are the causes of the other; and this priority of the impressions is an equal proof, that our impressions are the causes of our ideas, not our ideas of our impressions” (p. 53). Thus we observe the constant conjunction of impressions and ideas, as well as the temporal priority of impressions over ideas, and we infer that the two are causally connected, with impressions doing the causing. In Hume’s terminology, we believe his general proposition on the basis of “experience”—our experience of constant conjunction.

But this means that Hume’s own critique of causal belief applies to his guiding principle. In brief: our causal beliefs are not based on insight into the real powers of cause and effect but on mere constant conjunctions that could easily have been otherwise, and which interact with our instincts to produce non-rational beliefs of an inductive nature. It is like our knowledge of the actions of colliding billiard balls: the real powers are hidden and our experience of objects is consistent with anything following anything; we are merely brought by custom and instinct to expect a particular type of effect when we experience a constant conjunction (and not otherwise). Thus induction is not an affair of reason but of our animal nature (animals too form expectations based on nothing more than constant conjunction). Skepticism regarding our inductive inferences is therefore indicated: induction has no rational foundation. For example, prior to our experience of constant conjunction ideas might be the cause of impressions, or ideas might have no cause, or the impression of red might cause the idea of blue, or impressions might cause heart palpitations. We observe no “necessary connexion” between cause and effect and associate the two only by experience of regularity—which might break down at any moment. Impressions have caused ideas so far but we have no reason to suppose that they will continue to do so—any more than we have reason to expect billiard balls to impart motion as they have hitherto. Hume’s general proposition is an inductive generalization and hence falls under his strictures regarding our causal knowledge (so called); in particular, it is believed on instinct not reason.

Why is this a problem for Hume? Because his own philosophy is based on a principle that he himself is committed to regarding as irrational—mere custom, animal instinct, blind acceptance. He accepts a principle—a crucial principle–that he has no reasonto accept. It might be that the idea of necessary connexion, say, is an exception to the generalization Hume has arrived at on the basis of his experience of constant conjunction between impressions and ideas—the equivalent of a black swan. Nothing in our experience can logically rule out such an exception, so we cannot exclude the idea based on anything we have observed. The missing shade of blue might also simply be an instance in which the generalization breaks down. There is no necessityin the general proposition Hume seeks to establish, by his own lights–at any rate, no necessity we can know about. Hume’s philosophy is therefore self-refuting. His fundamental empiricist principle—all ideas are derived from impressions—is unjustifiable given his skepticism about induction. Maybe we can’t helpaccepting his principle, but that is just a matter of our animal tendencies not a reflection of any foundation in reason. It is just that when we encounter an idea our mind suggests the existence of a corresponding impression because that is what we have experienced so far—we expectto find an impression. But that is not a rational expectation, merely the operation of brute instinct. Hume’s entire philosophy thus rests on a principle that he himself regards as embodying an invalid inference.

It is remarkable that Hume uses the word “proof” as he does in the passage quoted above: he says there that the constant conjunction of impressions and ideas gives us “convincing proof” that there is a causal relation that can be relied on in new cases. Where else would Hume say that constant conjunction gives us “convincing proof” of a causal generalization? His entire position is that constant conjunction gives us no such “proof” but only inclines us by instinct to have certain psychological expectations. And it is noteworthy that in the Enquiry, the more mature work, he drops all such talk of constant conjunction, causality, and proof in relation to his basic empiricist principle, speaking merely of ideas as “derived” from impressions. But we are still entitled to ask what manner of relation this derivation is, and it is hard to see how it could be anything but causality given Hume’s general outlook. Did he come to see the basic incoherence of his philosophy and seek to paper over the problem? He certainly never directly confronts the question of whether his principle is an inductive causal generalization, and hence is subject to Humean scruples about such generalizations.

It is clear from the way he writes that Hume does not regard his principle as a fallible inference from constant conjunctions with no force beyond what experience has so far provided. He seems to suppose that it is something like a conceptual or necessary truth: there couldnot be a simple idea that arose spontaneously without the help of an antecedent sensory impression—as (to use his own example) a blind man necessarily cannot have ideas of color. The trouble is that nothing in his official philosophy allows him to assert such a thing: there are only “relations of ideas” and “matters of fact”, with causal knowledge based on nothing but “experience”. His principle has to be a causal generalization, according to his own standards, and yet to admit that is to undermine its power to do the work Hume requires of it. Why shouldn’t the ideas of space, time, number, body, self, and necessity all be exceptions to a generalization based on a past constant conjunction of impressions and ideas? Sometimes ideas are copies of impressions but sometimes they may not be—there is no a priori necessity about the link. That is precisely what a rationalist like Descartes or Leibniz will insist: there are many simple ideas that don’t stem from impressions; it is simply a bad induction to suppose otherwise.

According to Hume’s general theory of causation, we import the idea of necessary connexion from somewhere “extraneous and foreign”[2]to the causal relation itself, i.e. from the mind’s instinctual tendency to project constant conjunctions. This point should apply as much to his general proposition about ideas and impressions as to any other causal statement: but then his philosophy rests upon the same fallacy–he has attributed to his principle a necessity that arises from within his own mind. He should regard the principle as recording nothing more than a constant conjunction that he has so far observed, so that his philosophy might collapse at any time. Maybe tomorrow ideas will notbe caused by impressions but arise in the mind ab initio. Nowhere does Hume ever confront such a possibility, but it is what his general position commits him to.



[1]David Hume, A Treatise of Human Nature(Penguin Books, 1969; originally published 1739).

[2]The phrase is from Section VII, [26], p. 56 of An Enquiry Concerning Human Understanding(Oxford University Press, 2007).


Is Solipsism Logically Possible?



Is Solipsism Logically Possible?



It has been commonly assumed that solipsism is logically or metaphysically possible. I could exist without anything else existing. There are possible worlds in which I exist and nothing else does. I can imagine myself completely alone. Seductive as such thoughts may appear, I think they are mistaken; they arise from a confusion of metaphysical and epistemic possibility.

Suppose someone claims that this table in front of me could exist in splendid isolation, the sole occupant of an ontologically impoverished world—no chairs, planets, people, birds, etc. Well, thatseems true—those absences are logically possible. But what about the piece of wood the table is made of? This table is made of that piece of wood in every possible world in which it exists, so the table cannot exist without the piece of wood. But that piece of wood came from a particular tree—it could not have come from any other tree. So this table can only exist in a world that alsocontains the tree in question, since it was a part of that tree. The table and the tree are distinct existences, so the table cannot exist without something elseexisting—the tree that donated the part that composes it. The table is necessarily composed of that piece of wood and that piece of wood necessarily derives from a particular tree: there are necessities linking the table with another object, viz. the tree. Thus “solipsism” with respect to this table is not logically possible.

Now consider a person, say me. I could not exist without my parents existing, since no person could be thisindividual and not be born to my parents. This is the necessity of origin as applied to persons. In any world in which I exist my parents exist; more precisely, in any world in which I exist a particular sperm and egg exist (and they can exist only because of the human organisms that produced them). So my existence implies the existence of my parents. Therefore solipsism is not logically possible. But the existential ramifications go further: my parents cannot exist in a world in which theirparents don’t exist. And so on back down the ancestral line, till we get to the origin of life: no later organism can exist without the procreative organisms in its ancestral line. Every organism has an origin, and that origin is essential to its identity. But it goes even further, because the very first organism must have had its own inorganic origin, presumably in a clump of molecules, and that origin is essential to it—itcould not exist without thatclump existing. And that clump of molecules also had an origin, possibly in element-forming stars; so it couldn’t exist without the physical entities that gave rise to it. And those physical entities go back to the big bang, originating in some sort of super-hot plasma. So I (thisperson) could not exist unless the whole chain existed, up to and including certain components of the big bang. Colin McGinn could not exist without millions and millions of other things existing, granted the necessity of origin. I am linked by hard necessity to an enormous sequence of distinct particulars. I couldn’t be mewithout them.

Of course, there could be someone just likeme that exists in the absence of my specific generative sequence—though he too will necessarily carry his own generative sequence. Perhaps in some remote possible world this counterpart of mine arises not by procreation but by instantaneous generation—say, by lightning rearranging the molecules in a swamp. But even then that individual would not be able to exist without hisparticular origins—his collection of swampy molecules and that magical bolt of lightning. Solipsism will not be logically possible even for him. In any case, the question is irrelevant to whether Icould exist without my generative sequence: my counterparts are not identical to me. All we are claiming is that solipsism is logically impossible so far as Iam concerned—this specific human being. It is myexistence that logically (metaphysically) requires the existence of other things—lots of other things. I (Colin McGinn) could never exist in another possible world and peer out over it to find nothing but myself (at least throughout history–I might exist without any other organism existing at the same time as me, my parents both being dead). The same applies to any person with the kind of origin I have, i.e. all human beings.

Why do we feel resistance to these crushingly banal points? I think it is in part because we confuse a metaphysical question with an epistemological question; and we cannot answer the epistemological question by appealing to our answer to the metaphysical question. The epistemological question is whether I can now provethat solipsism is false: can I establish that I am not alone in the universe? In particular, can I establish that my parents really exist (or existed)? Maybe they are just figments of my imagination; maybe I was conceived by lightning and swamp. I cannot be certainthat I was not. I cannot even be certain that I have a body. I can establish that I think and exist, but I cannot get beyond that in the quest for certainty. So the existence of my parents is not an epistemicnecessity. If I could prove that I am a member of a particular biological species, then maybe I could prove that I must have arisen by sexual reproduction from other members of that species: but the skeptic is not going to let that by–she will demand that I demonstrate that I ama particular kind of organism arising by sexual reproduction. And I will not be able to meet that challenge, since there are conceivable alternatives to it (the hand of God, swamp and lightning, the dream hypothesis). Maybe I just imaginethat I am a biological entity with parents and an evolutionary history. So we cannot disprove solipsism in the epistemological sense: for all I know, there is nothing in the universe apart from me.

But this is perfectly compatible with the thesis that it is not in factlogically possible for me to exist without other entities existing along with me: for if I ama biological entity born by procreation, then my existence logically implies the existence of many other things. It is just that I cannot prove to the skeptic’s satisfaction (or my own) that that is what I am. I might come to the conclusion that I had no parents after all, but that will not make it the case that there are metaphysically possible worlds in which I had no parents—this is a matter of the facts about me, not my beliefs about the facts. Thus solipsism is an epistemic possibility but not a metaphysical possibility. It is just like the table being both necessarily made of wood (metaphysical) and also being possibly not made of wood (epistemic). Giventhat I arose from biological parents, I necessarily did; but it is an epistemic possibility that I did not so arise—I could be mistaken about this.

It would be nice to disprove solipsism, but it isn’t insignificant to show that it is not in fact logically possible, given the actual nature of persons. Persons are the kind of thing that implies the existence of other things (granted that we are right in our commonsense view of what a person is). In this they resemble many ordinary biological and physical entities, which also have non-contingent origins. We may feel ourselves to be removed from the world that surrounds us, as if we are self-standing individuals, ontologically autonomous—as if our essential nature could subsist alone in the world. But that is a mistake—we are more dependent on other things than we are prone to suppose. We are more enmeshed in what lies outside of us than we imagine. We suffer from illusions of transcendence and autonomy. We are not free-floating egos that owe no allegiance to anything else; we are essentially relational beings, our identity bound up in our history. We cannot be metaphysically detached from our origins, proximate and remote.

The same point applies to our mental states: they too cannot be separated from other things. Could this pain exist in complete isolation? That may seem like a logical possibility, but on reflection it is not: first, this pain’s identity depends on its bearer—it could not be thispain unless it had thatbearer; and second, the identity of the bearer depends on the kind of history it has. So this pain could not exist without the generative sequence that gave rise to its bearer, a particular living organism; and that depends upon billions of years of history, going back to the big bang (and before). There is no possible world in which this painexists and certain remote physical occurrences don’t exist. There are necessary links connecting present mental states with remote physical occurrences—from the joining of a particular sperm and egg, to the origin of mammals, to the production of chemical elements. My pains can’t exist in a world without me (you can’t have mypains), but I can’t exist in a world without my parents, and my parents can’t exist in a world without their remote primate ancestors, and these ancestors too had their own necessary origins. The pains that now occur on planet Earth (thosepains) could not exist in a possible world without an elaborate biological and physical history that coincides with their actual history.

It is an interesting fact that we recognize these necessities. On the one hand, we have quite strongly Cartesian intuitions about the person and the mind, which is why dualism and solipsism appeal to us—these seemlike logical possibilities. But on the other hand, we are willing to accept that the person and mind are tied to other entities with bonds of necessity—as with the necessity of personal origin. We recognize that the identity of a person cannot be radically detached from all extrinsic and bodily things—parents, sperms, and eggs. These are anti-Cartesian intuitions insofar as they dispute the self-subsistence of the self.[1]We are thus both Cartesian and anti-Cartesian in our modal instincts about persons. It is as if we know quite well that the self cannot be a self-subsistent non-material substance without logical ties to anything beyond itself, even though in certain moods we fall prey to such thoughts. We know that our essence implies the existence of other things—as demonstrated by the necessity of origin—and therefore solipsism is not in fact logically possible. We are modally ambivalent about self and mind, but not confused.


Colin McGinn

[1]Kripke mentions the anti-Cartesian consequences of the necessity of origin at the very end of Naming and Necessity(footnote 77, p. 155). What is surprising is that neither he nor anyone else seems to have noticed the consequences for solipsism (including myself, and I published an article on the necessity of origin in 1976). But it is really just a fairly obvious deduction from the necessity of origin (originally proposed by Sprigge in 1962, as Kripke notes).