Perception, Thought, and Language


Perception, Thought, and Language



I will reflect loosely (though not I hope sloppily) on some very general properties of the items listed in the title, with special emphasis on their interrelations. There has been a tendency to assimilate these three things, as if they are all variations on a single theme. Empiricism does this conspicuously: concepts and meanings are regarded as versions of percepts.[1] The senses are taken to be primary and thought and language are modeled on their deliverances. Each type of faculty deals in sensory contents: impressions and copies of impressions, basically. This type of view has been extensively criticized for excessive homogeneity. More recently, language has been taken as primary: concepts are to be linguistically defined, and concepts enter into perception. The mind’s basic form of representation is in language and all other forms incorporate it. Thus people see the world according to the categories present in their language (which usually means speech): they think in language and their thinking shapes their perception of reality. Sometimes theorists bracket one member of the trio, assimilating just a pair of them: thought and language are assimilated but not perception, or perception and thought are assimilated but not language (I don’t know of a view that assimilates perception and language but not thought). It seems to be supposed that deep commonalities must pervade the three faculties; they couldn’t be quite independent of each other. It is allowed that other faculties are separate, such as emotion or desire or will, but it is thought that perception, thought, and language are necessarily bound up with each other; they form a natural unity. The reason for this is perhaps the following: perception leads to belief, which in turn leads to assertion. You see an object, form a belief about it, and then make a statement expressing your belief. The three faculties work together, so percepts, concepts, and meanings must share a basic nature. Hence we have the idea that concepts and meanings are copies of sense impressions, or the idea that concepts and percepts are variations on words. Either we are fundamentally sensing beings or we are fundamentally speaking beings.

It seems to me that this leveling tendency is misguided: there is an irreducible plurality to the three sorts of faculty. First, let’s ask what the purpose of each faculty is. I trust I will not be thought eccentric if I suggest the following: the purpose of perception is to gain information about the world; the purpose of thinking is to solve problems; and the purpose of speech is communication.[2] These are not at all the same purpose. If we think about it from the point of view of evolution, perception evolved so as to get the benefit of up-to-date information about the environment, thought evolved so as to solve problems presented by the environment, and speech evolved so as to exchange information about the environment (as well as possible solutions to problems). Thought uses the information provided by perception in order to solve problems, while language transmits this information to other creatures, along with the conclusions of reasoning. The three faculties intelligibly interact, but it doesn’t follow that each is a variant on the others. They presumably evolved separately and at widely different times (speech evolved only recently), and they serve very different ends. I want to explore the possibility that they are quite unlike in their basic constitution.

The idea that perception and thought are fundamentally different is familiar under the heading of modularity: the senses are not modifiable by the cognitive faculty.[3] I will add to that two other properties possessed by thought (and language) but not possessed by perception: predication and productivity. In thought and speech we predicate properties of objects: we think and say that some identified object is thus-and-so. But we don’t predicate in perception; rather, we are affected by things in a certain way. True, we can be said to represent things in perception, but the same can be said of pictures yet they don’t predicate either. Predication is a certain kind of symbolic act, allowing for negation, truth and falsehood, truth-functional combination, etc., but perception is not capable of this kind of complexity; it is architecturally more primitive than that. Perception presents arrays of properties; it doesn’t single out properties for attribution as propositions do, whether mentally or linguistically. Predication presupposes an evolutionary advance over perception, enhanced cognitive powers. Connectedly, perceptual primitives are not productive in the manner of thought and speech: we don’t have the phenomenon of infinite potential, recursion, grammatical rules, verbs and nouns, transformation, nonsensical strings, etc. If perception were a form of language (“the language of sense”), we would expect that it would display the properties characteristic of human language, productivity chief among them: but it doesn’t. Thought has this kind of productivity (but see below), but perception doesn’t. Thus perception can never be the basis of concepts and meanings, contrary to empiricism. But likewise language and thought can never be the basis of perception, since it lacks productivity. Taste and smell, say, are nothing like thought and language, and the same for the other senses. True, there are sensory primitives, but they are not word-like—they don’t combine into grammatical wholes with meaning and truth-value. They have neither semantics nor syntax. The senses might be said to occupy adjacent mental cells to the cells occupied by thought and language, with communication between cells, but the occupants are different kinds of being. Seeing red, say, is not part of a sentential structure with all that that implies. Predication and productivity are not properties of perception.

Yet they are properties of both language and thought. Does that imply a fundamental unity between the two? There are two possible ways in which such unity might be thought to obtain: speech is essentially the expression of thought, or thought is the internalization of speech. It seems to me that these are at best exaggerations.  No doubt speech evolved for the same kinds of reasons that animal communication systems evolved (which is not to say that language evolved for these reasons[4]), viz. to share information about the environment and the animal’s inner states, as well as to intimidate, impress, cajole, command, vent, etc. There is no necessity for thought to exist in order for these functions to be performed by speech, i.e. the kind of problem-solving thought that mature humans possess. So speech is not necessarily the expression of belief. Also, speech need not replicate the structure of thought in order for it to perform its function—it could be a lot more primitive (as much of our speech actually is). It is true that human language has the same kind of structure that thought appears to have (though we know little about the nature of thought), but there is no necessity about the two sharing the same defining traits: so language is not required to mirror thought. Speech is a sensorimotor system that evolved separately from thinking and serves a different purpose, so there is no a priori reason why the two should share their structure. As to the idea that thought is internalized speech, that theory would certainly entail that thought and speech share their inner architecture, but it is highly implausible: we don’t begin by speaking and end up thinking by some process of internalization (still less do other animals). What is true is that human thought and speech seem to be made for each other, natural partners, but that does not entail that concepts are words or words concepts. People can think in the absence of speech and speaking (vocalizing) doesn’t require thinking. Problem solving is not the same as communicating. Speaking is a sensorimotor skill designed for communication; thinking is an internal capacity designed for reasoning. The two are joined, but they are not variants of each other. So it would be wrong to assimilate thinking and speaking. Thinking is silent while speaking is noisy, and there is a deep reason why this is so, issuing from their very different purposes. It could easily be that the first forms of human speech were disconnected from our problem-solving capacities, as is the case for other species with problem-solving abilities and communication skills; only later did communicative speech and thinking become connected. Thinking and speaking are not indissoluble talents possessed of the same basic structure.

It therefore seems to me that perception, thought, and language (speech) are separate faculties of mind, as ordinary language suggests. It is wrong to assimilate them. They are connected, to be sure, but they are not versions of each other. Each is composed of elements that do not compose the others, and their combinations don’t follow the same rules (thoughts cannot be nonsensical or ungrammatical in the way sentences can be, for example). It is actually surprising that thoughts and speech acts can share such properties as truth and reference, given how different they are (perception does not have these properties, though it may have analogues of them). Maybe their application to speech is entirely derivative upon thought and is not literally correct (“derived intentionality”). Sentences can be grammatical or ungrammatical, but can they really be (intrinsically) true or false? In so describing them are we thinking of them as embodied thoughts in some way? In any case, it is an interesting fact that we so readily talk in this way, given how different thoughts and utterances are—as different as both are from percepts, one would have thought. This is not something to be taken for granted but rather to be explored and possibly questioned. The default assumption should be that all three faculties are made of different stuff, organized differently.[5]


Colin McGinn


[1] Imagination could be added to the list, but I won’t consider it here, focusing instead on thought, to which imagination is closely akin.

[2] Notice that I say “speech” not “language”: the reason is that I am not concerned with language in the sense that includes a putative language of thought. Such a language would clearly be constitutive of thought by definition. I am concerned with language as most philosophers use the term, i.e. public spoken languages like English. Even if there is a language of thought, its syntax and semantics might be quite different from external spoken languages, so there is no guarantee that spoken language would provide any insight into this internal (presumably innate) language.

[3] See Jerry Fodor, The Modularity of Mind (1983).

[4] Language as an abstract structure could have evolved as an aid to thought not as a means of communication, possibly coexisting with a pre-existing system of communication (as Chomsky has long urged). A language of thought could evolve without having any input into communication. Speech as a sensorimotor system, on the other hand, almost certainly arose as a communicative vehicle, which is why it is audible (or visible in some cases).

[5] There is a well-known tradition that regards language as merely a more or less inadequate means of expression of thought, which is in its nature more nuanced and sublime than language can ever be. According to this tradition, language can never be the stuff of thought, only its inept vehicle; it is what we must perforce resort to in trying to get our thoughts across to other people. Such a view certainly seems plausible for animals and their means of expression: the inner lives of animals are clearly more complex than their relatively primitive signal systems can convey. Assimilating animal cognition to animal communication would be particularly unappealing. It is only in humans that language (speech) even approximates to capturing what is going on at the level of thought.


Heat, Color, Shape, and Taste


Heat, Color, Shape, and Taste



Galileo’s 1623 discussion of heat and related matters bears revisiting.[1] In it he formulates with particular clarity what later came to be called the primary and secondary quality distinction, using it to address the question of whether motion is the cause of heat. He begins by saying that people labor under the false impression that heat is a “real attribute, property, and quality that truly inheres in the material by which we feel warmed.” (185). He goes on: “Accordingly, I say that as soon as I conceive of a corporeal substance or material, I feel indeed drawn by the necessity of also conceiving that it is bounded and has this or that shape; that it is large or small in relation to other things; that it is in this or that location and exists at this time or that time; that it moves or stands still; that it touches or does not touch another body; and that it is one, a few, or many. Nor can I, by any stretch of the imagination, separate it from these conditions. However, my mind does not feel forced to regard it as necessarily accompanied by such conditions as the following: that it is white or red, bitter or sweet, noisy or quiet, and pleasantly or unpleasantly smelling; on the contrary, if we did not have the assistance of our senses, perhaps the intellect and the imagination by themselves would never conceive of them. Thus, from the point of view of the subject in which they seem to inhere, these tastes, odors, colors, etc., are nothing but empty names; rather they inhere only in the sensitive body, such that if one removes the animal, then all these qualities are taken away and annihilated. However, since we have given them particular names different from those of the primary and real attributes, we have a tendency to believe that these qualities are truly and really different from the primary ones.” (185) He then compares these secondary qualities to the ability of a hand to tickle, remarking that tickling is not an attribute inherent in the hand that tickles; rather, the tickling is “entirely in us” so that “if the animate and sensitive body is removed, it is nothing but an empty name.” (186) He sums up: “I do not believe that in order to stimulate in us tastes, odors, and sounds, external bodies require anything other than sizes, shapes, quantity, and slow or fast motions. I think that if one takes away ears, tongues, and noses, there indeed remain the shapes, numbers, and motions, but not the odors, tastes, or sounds; outside the living animal these are nothing but names, just as tickling and titillation are nothing but names if we remove the armpits and the skin around the nose.” (187)

This distinction, in one form or another, has become extremely familiar to us since Galileo’s time, and has shaped the way we think of perception and reality. It stands opposed to two other theories: (a) that all the perceived qualities of things are primary qualities existing independently of the perceiving subject, and (b) that all the perceived qualities of things are secondary qualities that reflect the inherent constitution of the perceiving subject. Galileo is suggesting a mixed position: qualities divide up into two kinds according to their relation to the perceiving mind, whether within it or without it. Perception partly reflects external reality as it intrinsically is, independently of the mind, and partly reflects the nature of the perceiving subject, having no basis in external reality. It is partly objective and partly subjective. Theory (a) goes along with a realist position on external reality; theory (b) goes along with an idealist position; Galileo’s theory contains both sorts of element, partly realist and partly idealist. The question he doesn’t address, though it is acutely raised by his remarks, is why perception should be thus mixed: why do we (and animals generally) impose these subjective qualities on external things? The question does not arise under theory (a) because all perceived qualities belong to external reality according to that theory, while under theory (b) all our perceptions are manifestations of our own nature. The question for Galileo is this: why is perception partly veridical and partly illusory? We can understand why it should depict reality as it is—that is arguably the point of perceptual representation—but what is the point of presenting us with illusory properties not possessed by external things? Why not be completely objective? Why build error into perception? Why confuse us about what reality is really like?[2] As Galileo says, people are generally wrong about the status of secondary qualities, so they are actively misled about reality: why does perception do that to us? Why are we so deceived by our senses, systematically so? From an evolutionary point of view, shouldn’t such error be selected against, bringing perception more into line with reality? Why does natural selection tolerate our lying eyes? Or: why would God build error so directly into our senses? Descartes’s evil demon may not have total dominion over us, but he seems to have a lot of sway over our powers of perception—he makes us form false beliefs whenever we perceive the world.

A natural answer is that our perception of secondary qualities exists to serve a practical purpose: it records similarities and dissimilarities that are useful to our survival. For example, colors allow us to make finer discriminations and act on them, and tastes and smells enable us to select the right things to eat. No doubt there is something right in this idea, but it faces a couple of queries. First, why not develop senses that directly respond to the objective properties of things, since there is always a primary quality basis for any perceived secondary quality? Why not perceive the actual chemical composition of foodstuffs or the actual wavelengths of light corresponding to different colors? Then the senses would not mislead and would get to the real facts. Second, why do the senses mislead in the way they do—why do they impute the qualities they impose to external objects? Couldn’t they color-code without making objects seem objectively colored? Couldn’t they operate more like pain perception or tickling? They seem to go out of their way to mislead. Locke talked about the possibility of “microscopical eyes”: if we had those we would have no need of secondary qualities, but could limit ourselves to real primary qualities, thus restoring perception to full veridicality. Galileo invented the telescope (or co-invented it), but if he had invented the microscope he might have suggested a way to do away with the perception of secondary qualities. This possibility provides, I believe, the missing part of the answer to our puzzle: the reason we perceive secondary qualities is simply that it is too hard to perceive the operative primary qualities. Notice that the perceived primary qualities are all gross properties, easily detectable by the senses—shape, relative size, etc.—but the primary qualities that underlie secondary qualities are apt to be fine-grained, microscopic, and not readily detectable. How could the tongue explicitly register the chemical composition of a gustatory stimulus? That would be way above its pay grade. How could the eyes deliver perceptions of light waves or photon barrages as such? Instead the mind (the brain) invents qualities to stand in for such imperceptible properties: it conjures up a range of qualities that substitute for the relevant primary qualities. Thus we obtain the advantages of more discriminating perception than can be achieved by the perception of gross primary qualities alone without the burden of penetrating to the hidden microscopic primary qualities of things. And the reason the invented qualities are projected outward is simply that it is simpler that way: you might as well perceive the stimulus as having the property in question given that this is generally the way perception works. If visual stimuli are already perceived as having primary qualities inhering in them objectively, it is less confusing to do the same for secondary qualities—make them also appear to be inherent in external objects. True, a type of perceptual illusion results, but it is not a harmful type of illusion, merely a shortcut to practical efficacy (it is not as if it leads to dangerously false judgments). We can suppose that millions of years ago this apparatus evolved in our fish ancestors and it worked well enough that it persisted in subsequent generations. This is why colors, feels, sounds, smells and tastes evolved—to take advantage of hidden properties without having to represent them directly. They are an economical way to tap into the less accessible parts of reality. God doesn’t need them given his omniscience, but animals must respect the limitations imposed by evolution. So the question raised by Galileo’s distinction can be answered, thus clearing the way for its acceptance.

I wish to observe that some of the senses do not represent primary qualities at all. I do not believe that smell, taste, and hearing represent anything but secondary qualities, while touch and vision do. That is, these senses don’t give us any perception of shape or size or volume or motion or distance; they deal only in the subjective qualities typically assigned to them. They can be supplemented by the other senses, such as touch in the case of taste, but in themselves they do not present any objective qualities of things, only such subjective qualities as sweetness and sourness, pleasant and unpleasant smells, musical tones, etc. With those senses alone we would have no notion of a spatial world, but only a world of subjective qualities. What this tells us is that these senses are concerned exclusively with the inscrutable objective properties that bear on the animal’s life, such as chemical composition and sound waves. By contrast, vision and touch deal with gross properties that can be detected by means of the representational resources of these senses—we can see and feel shape and size. So it is not the case that all senses present a mixed array of properties—some present a purely subjective array (but none present a purely objective array). In a sense, secondary qualities are the natural objects of perception, because they correspond so closely to biological needs without regard for depicting the objective properties of things; shape and size just happen to be objective qualities that bear on the organism’s welfare, while at the same time being gross enough to be perceptible. Taste qualities, by contrast, are not attributable to the mind-independent world, though they correlate with the objective features that provide nutrition (molecular composition ultimately). So in these cases the array of qualities is wholly invented by the mind and imposed on the world. Indeed, it may be argued that even in the case of touch and vision the spatial qualities that are perceived are also really mental constructions, since physics does not recognize such qualities in its ultimate description of things—maybe it’s all strings in a non-Euclidian n-dimensional manifold with no determinate shapes and sizes. It would be surprising if animal perception had the right set of categories for capturing the truly objective nature of reality. But putting that aside, we can say that perceived primary qualities are the exception rather than the rule, so the fact that secondary qualities fail to satisfy veridicality is not really a count against them. They must, however, demonstrate their practical credentials if they are to make their way into our perceptual systems.

I now turn to Galileo’s discussion of heat and motion. His view is that heat is a secondary quality: “I do not believe in the least that besides shape, quantity, motion, penetration, and touch, there is in fire another quality, and that this quality is heat. Rather, I think that heat is in us, so much so that if we remove the animate and sensitive body, heat remains nothing but a simple word.” (188) Thus he declares, “motion is the cause of heat” (189). This conflicts with a well-known doctrine of Kripke’s, namely that heat is identical to molecular motion. Kripke would say that heat (= molecular motion) causes the sensation of heat but it doesn’t cause itself. So motion does not cause heat itself but only the sensation of heat. Yet doesn’t it seem right to say that warmth and coldness are sensory properties of things, properties that our sense of touch can reveal? Couldn’t a plate have the property of being hot without the usual molecular motion? It could certainly cause the sensation of hotness without such motion, so long as the perceiver’s nervous system is hooked up in the right way; and wouldn’t that sensation have a certain sensory quality as its object? The property of being hot seems to be neither molecular motion nor the sensation of being hot: nothing would be hot in a world of molecular motion but no conscious subjects, but it is wrong to identify the quality with the sensation of the quality. I think we need to introduce an extra layer into the story: molecular motion, sensations of heat, and the quality of being hot (or cold). The structure is similar to the case of color: here too we need a threefold division—wavelength of light, sensation of color, and the color itself. The color is not identical to the wavelength but it is also not identical to the sensation of color; it is an extra ontological level. Perhaps we can say that “heat” is ambiguous: sometimes it means molecular motion but sometimes it means the sensible quality we perceive when we have sensations of heat, which is not identical to molecular motion.

Thus Galileo and Kripke can both be right, charitably understood: sometimes “heat” designates molecular motion (in a physics class, say), but sometimes it designates a certain sensory quality that we colloquially refer to with terms like “hot”, “warm”, “lukewarm”, “cool”, and “cold” (in the bath, say). We can reasonably say that the former causes the latter (as well as sensations of the latter), even though in one use “heat” designates molecular motion. Heat (= molecular motion) causes heat (= sensory quality). We might similarly wish to say that “red” is ambiguous, now designating a certain segment of the spectrum and now designating a certain sensory quality—the former being the “cause” (objective basis) of the latter. If we try to work only with motion and sensation, we have trouble explaining the sensation of heat, because the question must arise of what its object is. We can’t say that it is molecular motion because no such concept enters into the nature of the experience; we need something to constitute its “intentional object” (de dicto not de re). This is where hotness comes in: the sensation takes as object a certain quality known through experience, the quality we call “hot”. It is the same for “red”: the intentional object of experience is not the wavelength but a certain irreducible quality that we call “red”. Proceeding from the inside out, there is first the subjective sensation of something being red or hot; then there is the intentional object of this sensation, the quality of being red or hot; and then there is the objective phenomenon that causes the experience to occur (in conjunction with the subject’s nervous system), which might also be referred to in certain contexts with the terms “red” and “heat”. There is more structure here than can be captured by the simple dichotomy of heat (molecular motion) and the sensation of heat. This confuses the discussion and makes the correct position invisible. There is something right in what Galileo says and there is something right in what Kripke says; properly understood their claims are consistent—we just need to recognize the intermediate level of reality (neither subjective sensation nor objective motion). This intermediate level is an invention of the mind and is not to be found in the austere physical description of things, and it exists in order to take advantage of (phenomenologically) undetectable aspects of the physical world. It is tempting to characterize the extra level in dispositional terms: molecular motion has a disposition (power) to cause sensations of heat, as wavelengths of light have a disposition to cause sensations of color. This attempts to do justice to the mind-dependence of these qualities as well as their possession by external things. But we are not required to take the dispositional route; we can regard the properties in question as irreducible primitive properties of things.[3] And that enables us to give a simple and natural account of the content of the relevant experiences: they are experiences as of such irreducible properties (they don’t seem to be as of dispositions to cause experience). So the threefold account provides a pleasing picture of what is going on when a perceiver feels heat or sees color.


Colin McGinn

[1] The text I use is The Essential Galileo, edited by Maurice A. Finocchiaro (Hackett, 2008). The quoted material is from The Assayer.

[2] This question first intrigued me in The Subjective View (Oxford, 1983). Now, nearly forty years later, I have found an answer to it.

[3] I defend this position about color in “Another Look at Color”, reprinted in my book Knowledge and Reality(1999).


Existential Beliefs


Existential Beliefs



It is generally assumed in philosophy that we have a great many existential beliefs. We believe that objects in the external world exist, that other people exist, that we ourselves exist, that mental states exist, that space and time exist, etc. Maybe not everyone believes that atoms and numbers exist (or moral values or gods), but the ordinary person has many existential beliefs, not always expressed perhaps yet lurking in the background. It is assumed that the ordinary speaker expresses existential beliefs all the time—whenever he or she refers to something. Thus Russell’s theory of descriptions asserts that anyone who uses a definite description is expressing an existential belief, and the same is true for proper names and demonstratives. Existential beliefs are assumed to be the most common kind of belief there is, ten a penny–the mind is crammed with them. Whenever I look around the world I am having existential beliefs about what I see: this exists, that exists, the thing over there exists, etc. I am constantly employing the concept of existence–not consciously perhaps, not explicitly, but unconsciously, implicitly. Right now I believe that this cup exists, along with the coffee in it. During my dreams I believe a great many existential propositions (which are largely false). We are all, in this sense, existentialists.

But is this really plausible? Isn’t it awfully intellectualist? Do animals go around equipped with existential beliefs unlimited (assuming they can have some beliefs)? Do young children confront the world with a barrage of existential beliefs? Do you really form an existential belief corresponding to every object you perceive (“That is red, and it also exists”)? Does every speaker have a belief corresponding to the first conjunct of Russell’s analysis? It is true that we sometimes have existential beliefs, which get expressed when questions of existence have been raised—say, about God or atoms or other minds or numbers—but do we have them as a routine matter whenever we interact with things? Isn’t this just far too much thinking? The OED defines “exist” as “have objective reality or being”: do we really wield this concept all the time? Do little children think, “This doll has objective reality or being” as they play with said doll? And what does “have objective reality” mean—doesn’t it mean “does not have purely subjective reality”? Is this what passes through the mind of the average boy or girl, or chimp or dog? You might reply that such callow creatures at least take an existential stance towards the world—that they are in some way “ontologically committed”. That is, their general attitude and behavior indicate that they take things to exist in some way (fear and avoidance will play a role). That seems reasonable enough, but it doesn’t imply belief—they act as if they have an existential belief without really having one. Sometimes people have a genuine existential belief and may even give voice to it by using the word “exists”, but generally they do not—they are merely behavioralexistentialists. This notion would need some explaining, but at least it enables us to avoid the overly intellectualist position outlined. It enables us to say that a creature can be ontologically committed to x without believing that xexists (that would suit Quine given his skepticism about belief in general). It also enables us to recognize the centrality of existence to living beings without supposing that they constantly have existence on their minds—it does matter to living beings whether a thing exists or not (food, predators, etc.).

The indicated position would then appear to be as follows: only in rare cases does the existential stance manifest itself in the form of existential belief, typically when a question of existence has been raised. So someone might have acted as if God exists for his entire life and only recently come to believe that God exists—for the question might never have occurred to him before. Similarly, people might behave as if the external world exists without ever believing it to exist (or individual things within it), and only come to believe in it when questioned on the subject.[1] Suppose a person unreflectively goes about his business as if the world exists, never formulating a belief to that effect, and one day is confronted in the marketplace by a skeptic who makes him consider the question: he might affirm, “Yes, I do believe the external world exists”, having only just arrived at this belief. And let’s not say he implicitly believed it all along, because that would be nothing but a misleading expression of his behavioral stance (do children and animals have such implicit beliefs?). You need not believe something, explicitly or implicitly, in order to act as if it is true. The right thing to say is that philosophy can make you form existential beliefs you didn’t have before. Isn’t this a more realistic picture of our dealings with existence? Existence is certainly in our blood as living creatures, but it is not thereby in our beliefs.

This has a bearing on three philosophical issues: skepticism, realism, and reference. The skeptic cannot claim that our existential beliefs about the external world, other minds, etc. are unjustified, since we have no such beliefs in the normal course of things—the question has not arisen for us. Of course, he may rephrase his skepticism to question our existential stance, but it is not clear that stances are the proper objects of justification; so here is a possible route to blunting the force of skepticism—it is not denying anything we believed before the skeptic came along. We might respond, “I have no beliefs to that effect, so I am not troubled about their lack of justification”; and we could decline to form the beliefs the skeptic imputes to us. We never claimed to have justified beliefs about the existence of external things. This would explain why skepticism seems so irrelevant to the ordinary person: he or she never attempted to justify existential beliefs of the kind the skeptic is casting into doubt, having none. We were never in the belief justification business to start with; we were just living our lives in an existentially sensitive way (we had an existence-sensitive “form of life”).[2]

In the case of realism it need not be assumed that existential beliefs form the evidence for the realist thesis: a moral realist, say, need not assert that people have beliefs to the effect that moral values have objective reality—people are not moral realists in that sense. The question is rather whether their moral practice reflects a commitment to realism—whether they take a realist stance. Ordinary people are not moral realists or moral anti-realists if that implies certain sorts of existential beliefs, so there is no point in inquiring what beliefs they have on the subject; instead, we must look to their practices (Wittgenstein would approve). Nor do people believe that the existence of material objects is independent of sensory appearances, or disbelieve this; at most they act and talk in ways that may be interpreted along those lines. So there is no point in asking whether commonsense belief is realist or anti-realist about some given subject matter; there isn’t any such belief. Similarly for mathematical realism: people don’t generally have any beliefs as to the objective existence of numbers, though their actions may be more consistent with one position than another. This makes it harder to pin an ontological commitment on them in the absence of any belief on the matter. It is relatively easy to tell whether someone is a divine realist (or a ghost realist) since here people do have genuine existential beliefs—you can just ask them what they believe. But if they have no such beliefs they need to interpret their practice just as an outsider must. Generally, if you ask someone whether he believes that numbers exist or moral values or fictional characters, you will not get a straightforward answer, for the simple reason that he has never formed a belief on the question (unless he happens to be a philosopher). People only form existential beliefs of this kind when they are called upon to do so—and they may not be so called upon. Otherwise they tend to fumble.

In the case of reference we can junk the idea that speakers harbor existential beliefs with respect to their objects of reference (except in special cases). A user of a definite description or a proper name does not typically believe that his reference exists (though he doesn’t disbelieve it either). Child speakers are not brimming with existential beliefs to this effect—the question has not entered their little heads. Maybe we can say that they act as if their reference exists, but that falls short of actual belief. It is just not the case that a speaker thinks every time she refers, “My reference has objective reality” or “My reference has more than merely subjective reality”. She might not even have the concept of existence at all. Existential belief is a genuine mental state, to be sure, but its natural home is in certain special situations in which existence is questioned or debatable; as philosophers promiscuously use the notion it is a philosopher’s invention, vastly overgeneralized. If you look into the speaker’s head you will not find existential beliefs skulking there, unless they happen to be there for special reasons (references to God will typically involve existential beliefs, pro or con).

The philosopher is much concerned with the formation of existential beliefs—that may be thought to be his primary occupation (ontology)—but the ordinary person is not likewise obsessed. He or she does not resort to the concept of existence very often and only when pressed. We may grant on reflection that everything that is exists, but we don’t normally bother to form existential beliefs about the world. The concept, after all, is puzzling and problematic—philosophers and logicians cannot decide on its correct analysis—and people generally steer clear of it.[3]



[1] I don’t at all mean to endorse any kind of behaviorism here, merely to gesture at the whole range of actions and attitudes a living being brings to the world, no doubt involving emotion and desire as well as tendencies to act in certain ways.

[2] Here we might be reminded of Hume and Wittgenstein, not to mention Husserl and Heidegger.

[3] It is noteworthy that we don’t need to use the word “exists” in order to single out certain sorts of cases that don’t imply existence: we say that we were under an illusion or were hallucinating or dreaming or that Sherlock Holmes is a fictional character or that there are no such things as fairies. Seldom do we invoke the somewhat stilted word “exists”: it is philosophers who describe all these cases as failures of existence. Explicitly existential belief is an unusual state of mind, reserved for special occasions.  Philosophers are in it a lot, the folk not so much.


Skepticism and Self-Knowledge



Skepticism and Self-Knowledge



From the point of view of skepticism, self-knowledge is an anomaly. How is it that facts about a person’s psychology can be known with certainty when everything else is uncertain? It’s not as if first-person ascriptions of mental states are analytic or a priori; they report the same facts as give rise to the skeptical problem of other minds. We might think of this as the puzzle of first-person infallibility: how come we can’t be wrong about our own inner lives when we can be wrong about everything else? Of course, not everyone has accepted that we are thus infallible, even about whether one is in pain, but I think they fail to appreciate the force of the anti-skeptical position in this area; in any case, I will not attempt here to parry these assaults on introspective certainty. Instead I will offer a mixed position that accepts the standard claim of infallibility but finds one place at which the infallibility breaks down—so that such beliefs are not completely infallible, though they are largely so. General skepticism does not then run into an outright counterexample: all (empirical) knowledge is fallible one way or another.

So suppose I am in considerable pain as a result of stubbing my toe. I judge this to be so, uttering the words, “That hurts!” Could I be wrong? There are two places at which possible error might be supposed to creep in: with respect to the type of sensation I am feeling, and with respect to who has that sensation. Could I really be feeling another sensation altogether and misidentify it as pain—say, a pleasant sensation or a sensation of red? I could of course use the wrong word to describe my sensation (perhaps my English is shaky or I have some sort of language pathology), but that doesn’t mean that I misapply the concept of pain. I would agree with those who insist that no such thing is possible: I couldn’t be feeling a sensation of pleasure or a sensation of red and mistakenly suppose it to be a sensation of pain. I can’t misidentify my sensations in this way: I know with certainty what kind of sensation I am having—I feel that sensation directly and I apply the correct concept to it. What about the identity of the person feeling pain—could I misidentify him? I know that somebody is in pain and I mistakenly take that person to be me (actually it’s the person sitting opposite me). That again looks like a rank impossibility: I can’t judge that someone is in pain and wrongly suppose that I am that person. If I judge that I am in pain, I must be right about the identity of the sufferer: I know for sure that it is I who is in pain. Thus I cannot be informed that I am in pain once I have judged that someone is: I know it’s me just by knowing my own pain, unlike knowing (say) that someone in this room has won the lottery and being informed that it’s me. The pain presents itself as mine when it is mine. It is as if the pain has a little sticker on it saying, “This belongs to you”. Taking these points together, then, there seems no room for error in the self-ascription of pain: both possible points at which error might occur are blocked, so I know infallibly that I am in pain. I could never believe that I am in pain when I am really seeing red, or that I am in pain when it is really the person opposite me. By contrast, I could believe that my house is on fire when really it is merely well illuminated, or when it’s the next-door neighbor’s house that is in flames not mine.

So far, then, the case of self-knowledge is not parallel to the case of knowledge of the external world (or other minds). But there is one point of potential fallibility that we have not explored—the time of the pain. For I do not merely judge that I am pain at some time but at this time—I judge that I am in pain now. Could I be wrong about that? Could I misidentify the time of the pain? In particular, could a past pain be mistakenly attributed to the present time? Philosophical astronomers are fond of pointing out that the light reaching us from distant galaxies might have originated from a source that is now very different from what it was when the light departed from it, and might not now even exist. We have the impression that the object of sight is now as it seems to be, but that may not be so—and it is often not so. If we judge that that object is now thus and so, we make a mistake; rather, it wasthus and so. There is a time lag between when the light started out and when it reaches our eye, and this time lag can produce erroneous temporal belief. For instance, what looks like a contemporaneous stellar explosion could have occurred long ago. Taking a cue from this case, let us imagine a mind that is spread out across the universe at a scale of billions of miles: the brain that serves this mind is distributed as widely as galaxies are. In one part of it sensations of pain are processed, while in another part beliefs are processed, specifically beliefs about pain. Suppose it takes many years for signals from one part of this distributed brain to be received by the other part. Then the person whose brain this is may judge that he is in pain now when in fact the pain ceased long ago, say two centuries ago. He is quite correct to suppose that pain occurred in him but he gets the time of its occurrence wrong (we may suppose that he doesn’t know about the time lag). He thinks he is in pain now but in fact he isn’t. He makes temporal errors in his self-ascriptions of pain (as well as beliefs, emotions, etc.).

Now the skeptic sees his opportunity: couldn’t the human brain be subject to a similar time lag? In fact it is: it takes time for nerve signals to travel from the pain centers of the brain to its cognitive centers (located in the frontal lobes). It may be that by the time you judge that you are in pain the pain has receded, though no doubt you are usually still in pain at the time that you judge you are. The skeptic will then conjure the possibility, based in neurophysiological fact, that in any case of self-ascription of pain it is possible that the pain has ceased by the time you judge it to exist. You judge that it exists now, simultaneously with the judgment, whereas in fact it existed at a previous time, possibly a few milliseconds earlier or even months ago (maybe your brain is extremely slow). Perhaps you have been hooked up by a super scientist so that there is a time lag of five minutes between having a mental state and judging that you have it, so that all your self-ascriptions are false with respect to time (assuming the mental states don’t persist till the moment you make the judgment). Thus self-ascriptions of mental states are fallible, we might now be systematically making mistakes about the time of our mental states, and skepticism extends to self-knowledge (at least in this one respect). Nothing is therefore completely immune from skepticism; error is always possible (with regard to the empirical world anyway).

The reason that error is always possible is that fact and belief do not necessarily coincide. It is thus possible to believe that something is happening now that is not happening at that time: I might think that a certain lecture is happening now but in fact it happened an hour ago; likewise I can think that a pain is happening now but in fact it happened a second ago. There is the fact on the one hand and there is the judgment about it on the other. This division is as true for mental states and self-ascriptions of them as it is for anything else, so it is not surprising that error is possible here too; what is surprising is that it is confined to the temporal content of such judgments, having no parallel with respect to the identity of the state ascribed and who it is ascribed to. I can’t be wrong about what state I am in and about it being I that is in it—but I can be wrong about when the state occurs. I know for sure there has been pain in my life, but exactly when is subject to skeptical doubt. Maybe all my pain happened years ago and I am only now getting round to self-ascribing it: it just takes that long for the fact to make itself known to my introspective faculty. And the same is true of it seeming to me that I am in pain: this too could precede the act of judging that it so seems to me. The neural correlates of pain actually do precede the neural correlates of judging that you are in pain, granted that the relevant signals have to travel across the cortex in a finite time, so there is always a bit of a lag time between fact and report.[1] The skeptic simply amplifies this point to construct fanciful scenarios that dramatize the gap between fact and judgment. So we should add to the usual brain-in-a-vat case what might be called the brain-in-a-time-lag case.



[1] It is of course equally true that there is a lag between the time a stimulus leaves an external object and the time we have a perception of that object, which is particularly noticeable in the case of sound. This implies the possibility of error about the time of external events, as when you think that thunder (the physical phenomenon) occurs at the same time you hear it. Everything outside us thus happens slightly earlier than when we perceive it and make the corresponding judgment. It turns out that the same is true of events in one’s mind and judgments about them, which opens the case up to skepticism.


Roots of Skepticism




Roots of Skepticism



The roots of skepticism run deep; they are not merely the invention of insecure philosophers. Perhaps the most primitive form of skepticism begins from a simple thought: belief is not the same as fact. Beliefs are in the mind; facts are in the world. Thus beliefs and facts can vary independently of each other: unknown facts, non-factual beliefs. Beliefs don’t necessarily hook onto facts, since they can be false; and facts sometimes decline to reveal themselves. So there is a gap between belief and fact, and in this gap the skeptic sees the possibility of error and hence lack of knowledge. It would be different if belief and fact were identical: then there would be no gap and fact would follow from belief. Knowledge would be guaranteed. But as it is, there is no such convergence of belief and fact, so skepticism is possible. Call this “non-convergence”: we can then say that one root of skepticism is non-convergence; and it is clearly a basic property of belief in relation to fact. Skeptical scenarios such as the brain in a vat or the evil demon are predicated upon it; it is what allows for these possibilities (as an identity theory of belief and fact would not). It is as if knowledge craves identity with fact, but cannot achieve this identity, so skepticism gains purchase. The skeptic gazes out at the world and reflects that his state of mind is not identical to the fact he takes himself to know, so the assumption of knowing that fact is not well founded.[1] Notions like acquaintancehave been invoked to bridge the gap, but acquaintance is a relation between subject and object and hence presupposes non-identity; it cannot secure what knowledge apparently requires. So at least the skeptic suggests. Only identity would secure knowledge (the real McCoy), but that is an absurd theory of belief: belief and fact are distinct existences.

But there is another property of belief that is equally potent in triggering skeptical thoughts. This property is best appreciated in the wider context of the mind’s representational powers—what we might call the creativity of the mind. The mind is not a passive reflector of what comes in through the senses, faithfully mirroring what reality offers up. It creates mental representations: perceptions, dreams, illusions, hallucinations, imaginary objects, counterfactuals, nonsensical sentences, and erroneous beliefs. We might even say that it creates worlds, as with the brain in a vat or (more familiarly) dreams. It has the active power to generate representations that don’t correspond to facts—visual illusions being the most striking case. All of this has been fodder for skepticism: how can we rule out the possibility that the mind is always doing this? What is not often noted is that these skeptical thoughts trade on the fact that the mind has a certain sort of power or capacity: it is able to generate representations that fail to align with facts. Consider a mind that lacks such a power: it only stirs itself when facts heave into view. There are no dreams, no illusions, no imagination, and no false belief. Such a mind would not naturally lend itself to skeptical doubts: it would never say, “What if it’s all a dream?” or, “Maybe these perceptions are actually illusions”—for there are no such possibilities for this type of mind. This mind is not susceptible to skeptical worries simply because it never confuses fiction with fact or suffers a perceptual illusion or dreams a dream: it simply records what is actually present. It lacks the creative power necessary to produce the kinds of skeptical possibilities the skeptic is so impressed by. The human mind, by contrast, has this power in abundance; and it is this power that makes skepticism possible and natural for us. It is because the human mind is so creatively powerful that skepticism is so pressing for us. Skepticism arises from the strength of the mind not from its weakness. So we can add this property to the property of non-convergence as a source of skeptical sentiment. And clearly it too is a fundamental feature of the mind, as we know it to be. Skepticism thus has deep roots in the defining properties of the human mind (though not perhaps in all minds): we are natural skeptics because we know that our minds are such as to make skepticism possible.

I just described a possible mind in which skepticism can find no cause in creativity, which included the idea that such a mind has no false beliefs (possibly as a matter of natural law). But on reflection this thought experiment is not so obviously possible. What if I had claimed to describe a possible language in which no false sentences can be formed? Doesn’t the creativity of language guarantee that false sentences can be formed (they are well-formed and follow from the rules of grammar)? Similarly, if a person is capable of beliefs, isn’t she capable of having false beliefs? She just has to combine concepts in such a way that a false proposition results. The possibility of error is built into the ability to believe: to have beliefs about the empirical world is to have a mental attribute that makes error possible.[2] That is precisely why we have so many false beliefs. But if error is possible, then knowledge is not possible, according to the skeptic. So what makes belief possible is what makes knowledge impossible! Belief is only possible if error is possible (by virtue of creativity), but if error is possible then knowledge is not possible (by the skeptical argument): so belief can never amount to knowledge by its very nature. A pre-condition for the existence of belief is the possibility of error, but the possibility of error rules out knowledge, so belief by necessity rules out knowledge. That gives skepticism very deep roots indeed; it follows from the essential nature of belief, as a manifestation of human creativity. The creative mind is necessarily haunted by the specter of skepticism, and belief is necessarily creative.[3]

Now add to this the point that belief is a claim to know: when you believe a proposition you take yourself to know it. So thinking that you know is possible only if you can’t know! You can only think you know that p if you don’t know that p. The condition of thinking you know rules out the possibility of knowing: for thinking you know is an exercise of creativity, which implies the possibility of error, which implies the impossibility of knowledge. It is in the very nature of thinking you know that you don’t know (granted that the skeptic is right about knowledge requiring the impossibility of error). Thus belief can never amount to knowledge as a matter of its very constitution: it must contain the possibility of error, but then the skeptic seizes on that to question all claims to knowledge. I now know a priori that I cannot know, because I know that my beliefs arise from a creative faculty that permits the possibility of error, which rules out knowledge. I know that false beliefs are empirically common, and that I probably harbor many such beliefs; but I also know that there is no remedy for this situation–my belief system is so constructed that false beliefs can be generated by it. The system is a combinatorial generative faculty, like the language faculty, so the possibility of misrepresentation is built into it from the start. If (per impossibile) a belief system could restrict its outputs to those that correspond to facts, then this system would not be susceptible to the usual skeptical arguments; but that is a fantasy belief system, given that beliefs are combinatorial productions. It is like supposing that a dream system could be restricted to dreaming only what exists in reality.

Let’s assume the skeptical argument is correct: the possibility of error rules out knowledge. Then we can derive what deserves to be called a paradox of knowledge, namely that the conditions for the existence of knowledge make knowledge impossible. The conditions include the formation of beliefs (claims to know), but those conditions essentially involve the possibility of error, which is incompatible with knowledge. Knowledge is thus possible only if it is not possible! The skeptic has shown (granted his argument) not just that knowledge is impossible but also that it is in a certain way contradictory, for it requires an absence of error that is incompatible with its nature as a representational system. To know that p is for there to be no possibility of error regarding p, but that would imply that a necessary condition for being a belief system is not satisfied, which rules out the possibility of knowledge. Once a belief system exists the possibility of error exists, but that precludes those beliefs (claims to knowledge) from counting as knowledge. Skepticism is built into the very nature of belief as an instance of representational creativity. Creativity precludes knowledge (granting the connection between knowing and the impossibility of error). We could even say that concepts make knowledge impossible, because concepts are the things that make false propositions possible (just as words make false sentences possible). Concepts lead to the possibility of false beliefs, but that possibility rules out knowledge (as we are supposing). Suppose, for example, that I believe the table in front of me to be brown: I can reflect that this belief might be false, since my belief system might have constructed the wrong combination of concepts; but then I can’t be said to have knowledge that the table is brown. The point is that concepts in their nature can combine to create false beliefs, so skepticism has roots in the nature of concepts. Knowledge is therefore not possible for creatures that think in concepts—but what other way is there to think? We feel the pull of skepticism because we see that it has its roots in the nature of thought itself. The paradox of knowledge is that what allows us to seek knowledge prevents us possessing it—the structure of our cognitive faculty. The only way to vanquish skepticism is to do away with our cognitive faculty—but then we are left with nothing to know with.

The situation can be compared with perception. Our visual system purports to give us direct access to material objects, but according to the sense datum theorist it does not, but rather gives us direct access only to our own sense data. So we don’t really perceive what we naively think we perceive. But the point is not just that we happen not to perceive material objects directly, but rather that it’s built into the nature of perception that we don’t: for perception yields experiences and these are what is directly perceived (allegedly). The roots of the sense datum theory are thus claimed to lie in the very nature of sensory experience and are not dispensable—no one could see the world directly. Yet our experience leads us to believe that naïve realism is true. So there is something paradoxical about sensory experience: on the one hand, it presents itself as the direct perception of external objects; but on the other, its very structure contradicts that impression. It purports to do what its own nature precludes it from doing. So for the sense datum theorist naïve realism is not just a false theory of perception but also necessarily false, and reveals perception as paradoxical. Experience represents itself as doing what its own nature makes impossible. It endorses naive realism while also being incompatible with it. Similarly, our belief system represents itself as containing knowledge, but in its very nature it makes knowledge impossible. Experience makes us think we see the world directly, but at the same time its nature rules that out (according to the sense datum theorist); belief makes us think we have knowledge, but at the same time its nature rules that out (according to the skeptic). So the problems alleged by these doctrines go deep into the nature of the mind: the mind is telling us we can have states (direct perception, knowledge) that we cannot in fact have, given the way the mind is constituted. The nature of mind excludes its own assertions about itself.

I am not saying that skepticism is true, or that the sense datum theory is true; I am merely pointing out that both doctrines, rightly understood, go deeper than is generally supposed. First, they are necessity claims; second, they detect paradox in our ordinary concepts of knowledge and perception. In the case of knowledge, our concept requires something that is manifestly impossible, namely belief that is incapable of combining concepts in ways that fail to match reality. For once we accept that the mind has the power to create false beliefs we are well on the way to skepticism. This (combined with non-convergence) is what fundamentally leads to skepticism: belief is just not cut out to constitute knowledge.[4]


Colin M

[1] I discuss skepticism in relation to knowledge in this paper, but it would also be possible to frame the discussion using the notion of certainty or justified belief or other epistemic notions. Questions about whether knowledge really requires ruling out the possibility of error will not detain me, since I am concerned with what leads to skepticism in general; focusing on knowledge simplifies the discussion.

[2] I say “about the empirical world” so as to make a possible exception for introspective beliefs. Here it may be said that the combinatory power of concepts does not lead to the possibility of error, since I can know infallibly that I am in pain and yet my introspective belief is composed of a structured proposition. That would not contradict the claim that beliefs about the material world must be capable of error, but it might seem to limit the scope of the error thesis. This is a difficult question that I will not pursue here, but let me observe that there is a real tension between the idea of introspective certainty and acceptance of the combinatorial nature of belief: for how could a belief be incapable of falsity if its content is composed of combinable concepts? Shouldn’t skepticism carry over to so-called introspective knowledge? Not for nothing did Wittgenstein doubt that such statements are really propositional.

[3] It should be clear that by “creative” I don’t mean the kind of creativity we find in the arts and sciences but simply the kind of creativity inherent in the language faculty—what is sometimes called “productivity”.

[4] We might reasonably conclude that (some) animal knowledge is more immune to skepticism than human knowledge, on the assumption that animal knowledge is not always conceptual or belief-based. Certainly animals are not as troubled by skepticism as we are (though capable of error).


Evolution and the Self


Evolution and the Self



We must assume that the self evolved, given that it exists and is not a social construct. That means it arose by mutation and natural selection, serving some biological purpose. And not just in humans but also across the animal kingdom: all those animal selves are biological adaptations, like limbs and brains and senses. The reference of “I” is a biological entity—its characteristics are biologically adaptive. An organism without a self is at a reproductive disadvantage compared to one with a self (other things being equal). The self does something valuable, survival-enhancing. One of its characteristics is unity (or at least felt unity), so this unity must have a biological function—it must make the organism better at propagating its genes (having offspring). There must be a “gene for self unity”, as there is a gene for vision or language or sexual desire (many such genes presumably). The architecture of the self must be connected to its functionality, just as in the case of the body. This doesn’t mean that the self is reducible to the genes or anything else of a material nature; it just means that the self is biologically functional.

But what job does it do—how does it aid survival? We are now accustomed to the idea of the modularity of mind, according to which the mind consists of an ensemble of separate faculties, each with its own inner structure and function. This is the orthodox ontology in the study of the mind: each module is an evolved organ, to some degree independent of the others, though interacting with them—a suite of innate capacities much like the organs of the body. This picture has fuelled some skepticism about the ontological status of the self: what need is there for a self in addition to the several components that compose the mind? Is it just a pre-scientific holdover from common sense, dispensable from the science of the human organism? What job could the self perform that is not performed by the modules we already have on board? Why not go Humean about the self and regard it as at best a misleading way to talk about psychological modules? There are the modules and there is the set of them, with nothing else needed. But this position flies in the face of a stubborn conviction that the self is real—we feel it inside us, we refer to it with “I”, and ethics is built around it. We should at least inquire if there is some adaptive purpose that it plausibly serves.

Actually I think the answer to this question is not far to seek: the self serves an integrative function. The self imposes unity on what would otherwise be disorganized plurality. The modules by themselves are a mere motley, separate departments or agencies of the mind, with distinct (and sometimes competing) voices. They need to be brought harmoniously together: but interaction is not enough—we need unification. The self is a superordinate entity that creates this unity. Let me put the point in terms of the brain: each module corresponds to a brain region (possibly widely distributed) that interacts with other brain regions; but in addition to these there is a further brain region corresponding to the unifying self—the self-center, as we may call it. It has its own identity and is not just the sum of the several brain regions corresponding to the mental modules. Just so, the self is a real entity apart from the modules it integrates, but it exists because of its integrative function: it evolved as a distinct “organ” so as to perform the job of unifying the separate modules that make up what we call the mind. For example, the visual and speech centers are connected—this is why we can report on what we see—and the self is the entity responsible for creating that connection. Hence the perceived unity of the self: its job is to create order from chaos—to unite the several voices belonging to the modules. Without it the mind would be a cacophony of voices, an unruly choir, instead of the unified entity we know it to be. If we imagine the mind evolving one module at a time, starting with a single module, we can see that there is a problem of integration to be solved: the self is the solution to that problem, and in due course it evolved. The self is the means by which the senses (etc.) come together. Thus it is a mental faculty in its own right—a distinct component of the organism. The human organism has a heart, kidneys, a brain, vision, touch, thought—and a self. These are all adaptations occasioned by the usual biological pressures. The self has an adaptive biology just like the heart, which is not to say that it doesn’t differ from the heart in important respects (there is no need to say that both are “physical”). It is not epiphenomenal or fictitious or a mere by-product of something else: it has its own biological rationale. Biology needs to expand to include it (it is one aspect of the biological adaptation we call the mind). We may assume that the self made its entrance long ago, well before humans ever came on the scene; for its unifying powers were needed just as soon as organisms developed multiple modules that needed integration. Of course, selves became more sophisticated over time, as the mind became more thickly populated with faculties, but the basic element is presumably very ancient, no doubt evolving in the seas.[1] Then organisms could sense their own unity instead of being just a collection of autonomous modules. Selves piggybacked on modules, but they are something over and above modules; they certainly did not evolve before modules, since modules are their raison de’tre. They are how modules found their groove (the “groove theory” of the self).

It may be objected that there has to be something wrong with this picture, since modules contain mental states and mental states require subjects. If there is a pain module, it needs a subject for the pains to occur in—there is no subject-less pain. Experiences need bearers. But then the self could not have evolved subsequently to the modules and their contents: it was already present in the mere fact of experience. The point should be conceded, but it doesn’t refute the scheme I have presented, though it does call for a necessary distinction. Let us agree that the modules contain states that logically require bearers; that doesn’t imply that the self as it now exists doesn’t have an integrative function. The correct position is that the self has two basic ingredients: the primitive ingredient included in all conscious states (notice that this doesn’t imply a single self for each organism), and the higher-order integrative self that constitutes the reference of “I”. The structure of the self is thus two-tiered: the first tier as ancient as the first experiences to evolve, the second coeval with the onset of module integration. Your visual experience now has a subject-place logically built into it, but it also figures in the integrative actions of the self that unites it with other mental elements. We might call these the “subject self” and the “integrative self”. Both are evolved features of organisms, and both are presumably very old. Evolution builds on pre-existing structures, exploiting and repurposing them, and the self is no exception; it is a kind of tinkered together construction, made of primitive consciousness and higher-order integration. First, we have individual modules and the primitive subject; second, we have collections of modules and their unification into a single self. As is typical in evolution, there are no clear lines or unprecedented breakthroughs; everything is gradual accumulation and happy accident. The biological self evolved over eons, proceeding from earlier traits and driven by adventitious demands.

Animal selves are not all alike: it depends on the integrative needs of the organism in question. The bat must integrate its sonar experiences with its sense of touch, and both with its cognitive capacities. Thus we don’t know the nature of bat experiences and we don’t know what it’s like to be a bat self, since our selves don’t perform this kind of integration. Other animals don’t know what it’s like to be a human self, since our selves perform linguistic integration and theirs don’t. Integrative acts are common to different species, but not the items integrated. We know what module integration in general is like, but not the specific character of the integration an experientially alien species performs. What we would find really difficult to comprehend is a mind that lacked integration altogether—a purely modularized mind. Our minds are unified by our selves, but some possible minds may not be so unified; and this fragmentation is alien to us. We don’t know what it’s like to be a fragmented mind. Is it like having many selves or no self? Is there even a viable conception of self for such a mind? A new version of the problem of other minds would be this: How do I know that other minds are unified by a self as mine is? Maybe other people have fragmented modular minds with no unifying self to hold it all together (though their behavior may exhibit signs of unity). In some species there may be no single unitary self but several sub-selves (e.g. the octopus)

None of this is intended to solve the philosophical problem of the self, i.e. what the nature of the self is. The account is purely a theory of the biological function of the self—why it exists from an evolutionary point of view. It is easy to come to the conclusion that the self is biologically pointless–a remnant of the old notion of the soul perhaps–but the integration theory provides a rationale for the existence of the self as a product of evolution. How the integration works, what the nature of the self is, how it is realized in the brain—these are separate questions. But it may be helpful to start from a theory of what the self is designed to do, considered biologically. The existence of selves, in our species and others, is surely a biological fact, so we would expect there to be some biological function that selves serve. If consciousness helps us know the world, the conscious self helps us knit this knowledge together. It acts as a kind of counterweight to module plurality.[2]


[1] To some extent we are all piscine selves, originally designed to integrate information from a watery world, joined with fishy feelings. Simple selves (actually not so simple) peek out from behind aquatic eyes, the ancestors of our dry-land selves. The fish self is the prototype of us all.

[2] Notice that in a classic case of modular divergence like visual illusion it is the same self that entertains both mental representations–there are not two selves corresponding to the two representations. We don’t have one self that sees the lines as of unequal length in the Muller-Lyer illusion and another self that insists that the lines are equal; instead one self brings both representations together. I see the lines as unequal and I (the same thing) believe them to be equal. The modules pull apart, but the self holds them together. The self operates as a device of module convergence. Are there any psychopathologies in which modular divergence is experienced as a splitting of the self?