Against World-Making

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Against World-Making

There is a view out there, made respectable by Nelson Goodman, that the world is made not found—or rather, worlds, plural.[1] Worlds are versions, verbiage, visions (to parody Goodman’s alliterative style). They are not discovered, or uncovered; they are constructed, built. Is there any truth to this trope (merit to this meme)? Note that the view is not that our representations of the world are made; it is the view that the world itself is made. The world of nature is a mental production. Reality is reflection reified. Let us first observe that vast tracts of reality pre-date our existence, or that of any animal. There was a universe before there were reflective reifying beings, world-makers. How then could the world be made by us? Not by backwards causation, presumably, or time-travel. That pre-cognitive world had a nature, a way of being; it wasn’t just a formless blob in the void. It consisted of natural kinds of some sort. Moreover, it made us: we are the products of natural history, of pre-existing natural kinds. Indeed, our world-making is the result of the world, not its cause. More specifically, our bodies and minds are the outcome of genetic selection and environmental shaping—like all evolved organisms. And the made cannot make the maker: what made us is not made by us. Perhaps it is true that we make our representations of the world; they have their origins in us. Our language and way of seeing and conceptual scheme are features of us not antecedent reality, not the world that we try to represent. So, Goodman is quite wrong to suppose that the world consists of nothing but versions, a projection of our symbolizing tendencies. On the contrary, there had to be a world prior to our powers of description and depiction, because we came from somewhere somehow. History exists. On Goodman’s way of looking at things, we came into existence miraculously and proceeded to construct the world. Our brains are the source of all being, including our brains. But, of course, our brains are natural objects with a natural history; they are made by the world, not its maker. We are in the world; it is not in us. This is not to say that we are right in all our conceptions and perceptions of things: maybe we are mistaken about the world as it pre-existed our existence. Nor is it to say that our concepts are guaranteed to capture the natural kinds that pre-date our thinking about them. It is only to say that some sort of world had to exist in order to give rise to beings like us, capable of forming versions and viewpoints. In fact, we have a pretty good idea of what this world was like, but the claim that there had to be a ready-made world is not committed to the idea that our epistemological capacities are infallible guides to it, or even on the right track. Metaphysics is not epistemology. The point is that we are not world-makers; the world is a mind-maker. This will not be disputed in the case of other animals; they don’t create the world they live in by constructing versions of it. But Goodman is strangely silent on their world-making powers; it is the human animal that gets to make the world as it is. You would never guess from Goodman’s text that we evolved from earlier types of organism. Does he think that at one point in the distant past the world was the upshot of dinosaur world-making? Or is it that the world had to wait for human construction in order to spring into being? That is a pleasingly anthropocentric view of things but hardly historically realistic. For Goodman, we stand outside of time and arbitrate what goes on in time. He forgets that we are effects as well as causes. But is he completely wrong about world-making? He is not: much of what he says is perfectly reasonable, though exaggerated. We do construct worlds, impose categories, initiate realities. All of the arts are instances of world-making: literature, poetry, painting, music, theater, architecture, dance. These are human productions, though based on naturally given objects and laws. It is literally true that in literature we create fictional worlds. Art is made not found. It is also true that we impose our minds on the natural world: in our systems of measurement of time and space, in our classifications of things as edible or not edible, in our perceptual categories (color is plausibly seen as imposed not detected). We also construct social reality: money, marriage, social class, political systems. Our classifications are often interest-dependent not objectively determined. Our concepts are mainly species-relative. Truth is not the only measure of symbolic rightness or representational worth (what about painting?). The constellations are human choices not astronomical givens. Musical styles are not beholden to acoustic science. In all this we can agree with Goodman: not all aspects of the world are independent of the human perspective; we are inveterate world-makers. But notice that even these acts of making have their own inner reality: they have a nature of their own not created by human hand or eye. Thus, language itself is a natural phenomenon with an objective nature; we can’t just decide what language is, though we can decide how to use it to create fictional worlds. Language is factual not fictive (to employ a Goodmanian opposition). So is painting, music, etc. All symbols (in the broad sense favored by Goodman) are symbols in themselves not by fiat or fabrication. A tailor’s sample (Goodman’s example) is an item in the world not a figment or fancy. Figments and fancies in themselves have a psychological nature that can be investigated. Versions and visions have a reality that calls for objective study. We don’t make our own psychology as if from nothing. The laws of the mind are as real as the laws of physics, if less strict. The science of psychology is not an exercise in world-making, like imaginative literature. So, yes, there is a whole lot of world-making going in, but not all thinking is world-making, and what is has its own non-negotiable reality. In some cases, there can be genuine dispute as to whether we have a case of world-making or world-discovering—mathematics and morality are prime examples—but in other cases we are clearly under the thumb of nature not its architect. It’s not versions everywhere and all the way down. It’s not irrealism and relativism wherever you look—though certainly there is some of that (e.g., fiction and food preferences). Nature made us (we didn’t make nature), and we proceeded to construct our own worlds (I don’t disdain the term), and it is not always easy to see what belongs to what; but the idea that the entire world (including our psychology) is made by us is preposterous and demonstrably false. Moreover, all this is obvious, platitudinous, and banal. Denying it has all the attractions of novelty for its own sake and the excitement of intellectual daring, but it is not at all plausible.[2]                    

[1] See Ways of WorldMaking (1978). The book is enjoyable to read, sometimes sharp and perceptive, but vague at crucial points, especially when it comes to distinguishing worlds from what is said about them. Goodman eschews merely possible worlds, on the grounds that he doesn’t believe in them, even though they are prime candidates for the thesis that worlds are made not found, fabricated not discerned, fabulous not factual. Goodman’s worlds are all actual, all parts of this world. I suspect his main motivation is to ensure a reputable place for art in the panoply of the respectable—to locate aesthetics in the space of metaphysics. It isn’t that art is disreputably merely imaginary while science is resolutely factual; rather, everything is really imaginary when you get right down to it. Everything is artifact, artifice, artistry. Truth is just one kind of creative achievement (his wife was an artist, he an art dealer). Art is not inferior to science or philosophy on account of its unreality, because these subjects too traffic in the unreal. Physics is not so different from cubism.    

[2] So why are people tempted by such views? I suspect it is simply because it is easy to conflate worlds with views of worlds: the phrase “our world” is ambiguous between these two things—does it mean ‘the world-as-we-conceive-it” or does it mean “the world-as-it-actually-is”? Of course, our conception of the world is in us, but it doesn’t follow that the world itself is in us. Language is in us, but not what language is used to talk about. We can’t conceive the world without conceiving it, to be sure, but that doesn’t mean that the world is intrinsically constituted by our acts of conceiving. Does anyone believe that the world owes its existence to the conceptual resources of the armadillo (except a Goodman of the armadillo species)? A use-mention confusion lurks behind all such ideas and conceals their complete wackiness.     

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Geometrical Knowledge

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Geometrical Knowledge

How do we come to have geometrical knowledge? How do we acquire geometrical concepts? The question has been around since Plato and his theory is still probably the best—we have such knowledge innately. But this doesn’t answer the question of what triggers the innate knowledge (it isn’t there fully formed from the start): what in our experience enables the innate knowledge to enter our consciousness in explicit articulate form? It can’t be Socratic interrogation because someone has to have the knowledge without such interrogation, and obviously most people don’t learn what a triangle or circle is by explicit verbal instruction. Is it by seeing shapes, or touching them? But how do we see and touch shapes—how does our experience come to have this kind of geometrical content? You might suppose that triangles and circles are present in the stimulus as it reaches the sense organs, ready to picked off like apples from a tree, but this is not the case. The pattern of light that impinges on the retina is notoriously fragmented, fluctuating, and fleeting; yet the concepts of geometry are fixed immutable forms, as Plato emphasized. The proximal stimulus is remarkably impoverished compared to the representational powers that exist in the mind; no mere copying process could produce the latter from the former. You can’t make a Euclidian purse from a retinal sow’s ear. In fact, as we now appreciate, the visual system makes elaborate computations that lead from the mess on the retina to a stable, intelligible, three-dimensional sensory world—a world of shaped objects in space. We see an objective world of determinate forms based on a stimulus that is anything but, thanks to our sophisticated visual processing mechanisms. Vision science investigates these mechanisms and it has made impressive progress. Can we conjoin this with Plato’s innateness hypothesis to answer the question of the origin of geometrical knowledge? It sounds like a promising idea, but we need to be more specific about the eliciting stimulus that triggers the innate schematism: what is it exactly that causes geometrical understanding to form in the mind? There is an innate structure in the mind-brain of unknown character, and somehow the course of experience elicits it; but what is it about the perceptual system that makes it suitable for performing this role? What does it do that leads to the formation of geometrical understanding? I suggest the following: it works by means of perceptual constancies. As is well known, the visual system (and tactile) corrects for variations in the proximal stimulus that result from changes of distance, illumination, perspective, and so on. It extracts distal invariants from proximal variations, thus producing a world of objective forms from an array of idiosyncratic subjective impingements.[1] These forms—shapes, among other qualities—constitute the geometry of the human visual world. They are generated by a process of correction applied to the proximal stimulus. Thus, we perceive cubes and spheres and other forms that are not subject to the vagaries of the proximal stimulus. The visual system attributes these forms to distal objects. This is not to be understood as a process of conscious rational thought but as an automatic unconscious computational mechanism (unreasoning animals have it too). Perceptual constancies are primitive properties of visual systems, which can occur in creatures that lack rational thought. However, in the case of humans rational thought does coexist with perceptual constancy, and an innate potential for geometrical understanding comes with the genes; in humans, geometrical knowledge can flower. We have the conception of geometrical forms as fixed determinate shapes with specific properties by virtue of a combination of innate schematism, rational thought, and perceptual constancy—with the last of these doing the heavy lifting. This is the capacity that triggers the formation of geometrical understanding, given the right innate structure. For it deals in perceptual invariants, objective shapes, a repertoire of determinate geometric forms—not in flickering patterns of light striking the retina. There is no geometry worthy of the name in the patches of light that cause nerve endings to fire in the retina, but by the time the visual system has done its work a fully formed geometry has been attributed to the distal environment. It only remains for this visual geometry to interact with the system of representations we call “innate ideas” and we have the roots of geometrical understanding—concepts of triangles, circles, etc. Perceptual constancies are vital to this process of cognitive production. It isn’t that distal objects somehow emit shapes that end up on the retina and can be copied by the brain to yield shape concepts; the shapes have to be generated by the visual system from clues contained in the proximal stimulus. Perceptual representational content is endogenously generated from perceptual primitives and then attributed to the environment; geometrical knowledge, as we ordinarily conceive it, results from the interaction between this system and the innate endowment we bring with us into the world. It is as if the innate geometry lies dormant in us until stimulated by the operations of the perceptual systems as they impose constancies on the data of sense. This capacity arises early in all perceiving creatures, so human children are primed to output geometrical competence before the school years begin: they are then ready for formal geometrical instruction. They know what triangles and circles are well before they are taught their mathematical properties. They have been having experiences as of triangles and circles from an early age—forms subject to perceptual constancies—so they are acquainted with geometrical figures; they just need to attach these perceptual primitives to their innate system of “ideas”. The triggering is perceptual, but not in the way the old empiricists supposed, i.e., by a copying procedure; rather, perceptual constancies play the eliciting role. Not that any of this is easy to understand—the nature of the innate schematism, the act of triggering—but it is the general character of the formation of geometrical knowledge. In the case of language an innate schematism is triggered by verbal sensory input, and the child comes to understand what words and sentences are (a basic level of grammatical knowledge); in the case of geometry the same kind of thing happens, only here the innate schematism is triggered by a perceptual system that is built around constancy effects. When a ball, say, moves away from the perceiver, retaining its apparent size as the retinal image shrinks, this embodies the idea of a geometrical form that persists across space and time; it is an invariant in a world of variation. It is the primitive prototype of Plato’s eternal geometric forms existing in a flux of fleeting impressions. Constancies imply permanence amid change, and that is precisely what Platonic forms are supposed to be. Geometric objects are constancies idealized.[2]

[1] For a thorough discussion of perceptual constancy, see Tyler Burge, Origins of Objectivity (2010) and Perception: First Form of Mind(2022).

[2] Our knowledge of color is not dissimilar. There is also color constancy and this affects our conception of color: we don’t think of colors as varying with every change of illumination, etc. We think of colors as invariant under variation of proximal stimulus, and hence as possessing a certain sort of objectivity. We can then study colors as stable qualities with a fixed nature. If colors and shapes were conceived as varying with the proximal stimulus, we could hardly study them at all—they would be too fleeting and lacking in any fixed nature. They would not be colors and shapes as we know them (there would be no such thing, for us, as the color red or the shape square).

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Quantifier Logics

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Quantified Logics

Standard propositional logic contains no quantifiers. It simply replaces sentences with propositional variables (“schematic letters”) that remain unbound. But there is nothing to prevent us from introducing quantifiers that bind these variables, ranging over propositions. These can be objectual or substitutional, according to taste. They will be read “for all p” and “for some p”. One might well think this enrichment was implicit all along, since the standard formulas are intended to express generality; that is why they contain variables not actual sentences. If we say “p and q entails p”, we mean to express the proposition that for any propositions p and q, if p and q, then p. Generality implies quantification. Adding the quantifiers will increase expressive power, but not beyond what was there all along. Thus, we can envisage two styles of propositional logic—quantified and unquantified. Each is legitimate and each can be studied in its own right. One might well regard the quantified form as more intuitive and natural; we can say things like “Every proposition has a negation” if we avail ourselves of this resource. In the case of predicate logic, as standardly rendered, we already have quantifiers built in: they bind the individual variables used to analyze the structure of whole sentences (along with predicate letters). But this is not essential to predicate logic as such: we could construct a notation that omits quantifiers and simply deals in formulas such as “Fx” and “not-Fx”. That is, we could do what we already do in propositional logic—write formulas that contain only unbound individual variables. This would be a quantifier-free predicate logic. The concepts of predicate logic and (first-order) quantificational logic are different concepts–just as propositional logic is different from quantified propositional logic. Adding quantifiers increases expressive power in both cases, though it is natural to suppose that this was implicit all along. Why not treat the two cases as essentially alike? As things are, we don’t, but this seems arbitrary—perhaps betraying dark suspicions about propositions as values of variables. In both cases we trade constants for variables, which allows for generality, and then introduce quantifier expressions to obtain the necessary expressiveness. But that is not the end of the line: we also have predicate expressions to deal with. They too have been introduced to allow for generality: instead of “red” and “square” we have “F”, intended to stand in for any natural language predicate. First-order predicate logic leaves these unbound, but there is nothing compulsory about this; there is nothing ill-formed about binding these variables with a quantifier. If we do, we get second-order predicate logic—where now the variables range over properties or some such. We have gone from an unquantified logic to a quantified logic—just as in the other two cases. And this was implicit all along in view of the generality conveyed by the usual formulas. So, now we have three sorts or levels of quantification: over propositions, over individuals, and over properties. Fine—we have such things to talk about and we want to make general statements about them. That is what the logical notation is designed to do. Is that the end of the line for quantification? No, because there remain constants not yet converted to variables that we also want to generalize about, viz. truth-functional connectives. We could introduce a variable over truth-functions, say T: then we could say things like “For any truth-function T, T is expressible in standard propositional logic”. We are quantifying over truth-functions, just as we quantified over propositions, individuals, and properties. This could be called “Quantified Truth-Function Theory” and added to the curriculum. We might think of it as involving third-order quantification. Now we have a fourth type of logic (or logical notation) to be added to the previous three. Each type is a counterpart to the quantifier-free logic that exists alongside it, and is a natural extension of it. Is that the end of the line for quantifiers? Not quite, because we still have one more type of constant left—the quantifiers themselves. Can’t these also be gathered under a suitable variable, thus allowing for generalized statement? Thus, we can say “For all quantifiers Q, Q admits of quantifier nesting”. This quantifier might range over the two standard quantifiers “all” and “some” or it could include the so-called non-standard quantifiers like “most”, “many”, “several”, “a few”, etc. The motivation is the same as before and so is the procedure: we want to talk generally so we replace constants with variables and introduce the necessary quantifier—in this case a quantifier over quantifiers. Thus, we obtain a quantified quantifier logic; we could think of it as concerned with the logic of second-level functions a la Frege, i.e., functions from first-level functions (corresponding to predicates) to truth-values. This we could describe as fourth-order logic—one step up from the logic of truth-functions. And with that we have covered all the constants that occur in the formulas of predicate logic; there is nothing left to quantify over. We now have five levels of quantified logic applicable to quantification over propositions, individuals, properties, truth-functions, and quantifiers themselves (construed as second-level functions). Each level has a non-quantificational counterpart—a logical system that lacks the quantifiers contained in its more expressive twin. This is the right way to understand the structure of the logical universe, not the familiar division into non-quantificational propositional logic and quantified first-order predicate logic. That is just a partial glimpse of full logical reality, an oversimplification of the space of logical systems.[1]

[1] Of course, we must also add modal logic (and perhaps other types of logic), which invites new quantifiers and variables so that we can generalize about modal categories, as in “All modal operators M admit of nesting with other modal operators”. Quantifiers are not limited to the role they play in standard first-order logic; they crop up everywhere. Quantifier pluralism is the way to go.

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Other Bodies

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Other Bodies

The orthodox view of our knowledge of minds is that while other people’s minds are doubtful my own mind is not: I can be certain of my mind but not of other minds. Hence there is a skeptical problem of other minds but not of my own mind. There is a deep epistemological asymmetry between self and other. However, it is not thought that there is a comparable asymmetry with respect to the body: the existence of other bodies is doubtful, but so is the existence of my body. I might be a brain in a vat with no body, and other people’s bodies might be hallucinations; there is a skeptical problem about both. Now that I don’t contest, but it doesn’t follow that there is no epistemological difference between my knowledge of my body and my knowledge of other bodies. I could be more certain of my body than I am of other bodies, and the ground of my knowledge might be different in the two cases. So, let’s explore the question. How do I know other bodies (human, animal, and inanimate)? I know them by sense perception, notably vision. But sense perception is subject to illusion and hallucination, so that source of error has to be recognized. How do I know my own body? By sense perception, to be sure, but also by direct knowledge of what I am doing, by proprioception, and by sensation (feelings in my body). So, I have more evidence about my body than I have about other bodies—more to go on, more to appeal to. Moreover, I don’t have hallucinations of my own body as I have hallucinations of other bodies—I never have impressions of my body existing when it does not, as I have impressions of other bodies existing when they do not (as when I have a false impression of someone lurking in the dark, etc.). Also, I am always (when awake) aware of the condition of my body, even when I can’t perceive it with my five senses, but this is not true of other bodies. I can’t have proprioception of other bodies, but proprioception of my own body is ever-present and highly reliable. All in all, I am in a solid position epistemologically with respect to my body: I know my own body remarkably well, even if I can’t be certain I’m not a brain in a vat. It’s really the best-known physical object in the world as far as I am concerned. I would venture to suggest that the probability of my body existing is a good deal higher than the probability that other bodies exist. I am more ready to accept body solipsism than the hypothesis that other bodies exist but mine doesn’t. I’m pretty damn sure my body exists! Yours, well, that’s more a matter of speculation, faith, received wisdom. Every night I dream of bodies that don’t exist, but I never dream of my own non-existent body. But is this something I can defend against a determined skeptic? Actually, no, except to a limited degree, but this degree marks a difference between my body and yours. For I can argue that I must at least have a brain, while your brain is up for grabs. This is because I know with certainty that I have a mind, and my mind needs a brain; but I don’t know with certainty that you have a mind, so I can’t infer from that that you must have a brain. I can’t move from knowledge of your mind to the conclusion that it is housed in a brain, because I don’t have that knowledge; but in my case, I have indubitable knowledge of my mind, so I have a solid basis for the move to a brain. Thus, I have a Cogito-type argument for a body part belonging to me, but I have nothing comparable in your case—you could be all hallucination as far as I am concerned (though not as far as you are concerned). There is no Cogito-type argument of the form “I think, therefore you have a body”, but there is such an argument as “I think, therefore I have a body”—where the body I have perhaps consists just of a brain. Can I infer the existence of any bodies other than my own from the existence of my body (even if that is just a brain)? In the case of the mind, that looks to be infeasible: I can’t infer from the existence of my mind that any other minds exist or ever existed or will exist (solipsism-of-the-moment is inescapable as a skeptical possibility). But in the case of the body the prospect of other bodies looks brighter: because I can infer from the existence of my body that other bodies didand will exist. The reason is that the matter of my body did once belong to another body and it will later come to belong to a separate body too. The matter of my body moves around composing different bodies at different times, but the “matter” of my mind does not. Thus, my bodily matter survives my body’s demise, as it once survived the demise of another body or bodies; but my mind does not likewise persist through time—it is limited to me. So, I can know that other bodies once existed and will exist, given that I know that I have a body—not so for mind. This thinking thing might be the only thinking thing that ever existed or will exist, but this extended thing is one among many extended things spread out in time—that is its nature. I can assert “I am an extended thing, therefore there must be other extended things (at some time)”, assuming that a past and future exist during which my matter exists and my body doesn’t. My body implies other bodies (on reasonable assumptions) but my mind doesn’t imply other minds; and this point applies equally to my brain alone. (But, of course, I can’t infer that your body exists in this way, since your body is not composed of the matter that composes mine.) In short, I know more about my body than I know about your body; so, I have more of an other-body problem than a my-body problem (though I do have somewhat of a my-body problem). It is true that I cannot be certain that I have a body just as I experience it, but I can be certain that I have some sort of body (even if it’s just a brain quite unlike the one I think I have). However, I really can’t be certain that you have a body of any kind, since you might just be a figment of my imagination, an outright hallucination. Accordingly, it is too simple to say that there is no epistemological asymmetry between my knowledge of my body and my knowledge of your body: I am better placed to know my own body, and in several ways.[1]

[1] In the Matrix people hallucinate their body and are quite wrong about what it is up to, but they can’t hallucinate the fact that they have some sort of body, since that is a precondition of their having a mind at all. But there is no conceptual bar to hallucinating other people’s bodies in toto; they need not have any physical reality at all.

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Academic Blacklisting

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Academic Blacklisting

A few weeks ago, a fellow philosopher suggested to me that it would be a good idea to produce a book of essays discussing my work, which he would edit. I agreed. He contacted Wiley publishers and received a highly enthusiastic response from their commissioning editor Will Croft. It only remained to sign the contract and have the project approved by the editorial board. On September 14 he received a letter from Mr. Croft reversing the earlier enthusiasm, saying: “When the project was discussed and put to the editorial board, it was felt that it was inappropriate to move forward, and there were also market concerns, given the controversy surrounding Professor McGinn. After careful consideration, we are unable to proceed to the next steps.” So, if there is “controversy” surrounding a potential subject for an academic book, this publisher deems it “inappropriate” to publish such a book. Notice that there is no claim here about the truth of anything in the “controversy”; it is thought sufficient merely that “controversy” exists. This is appalling enough in itself, but consider the implications. It is now ten years since the alleged “controversy” flared up, so there is no reason to believe that Mr. Croft and his colleagues are willing to put any time limit on their ban, since the “controversy” will continue to have occurred. Presumably, then, it will be policy until the time of my death. But more than that, it would be deemed acceptable to extend the ban after my death, perhaps in perpetuity, since the “controversy” will be an historical fact. This means that, irrespective of the merits of the “controversy”, and no matter the loss to the academic community, and no matter what readers may demand, Wiley will decline to publish anything about Colin McGinn for the foreseeable future. If other publishers were to take the same line, that would mean that for the rest of time no one will be allowed to publish anything about me, despite the quality of what may be produced. Surely anyone can see that this is absurd, unjust, foolish, imprudent, unethical, and downright stupid.

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Cogito for the External World

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Cogito for the External World

The traditional Cogito “I think, therefore I am” yields a moderate harvest of existential conclusions: the existence of a subject of thoughts (albeit momentary and etiolated) and the existence of propositions as the content of thoughts. We might compare this to a plant that is rooted in the earth and directed to the sun (earth as subject, sun as proposition). The plant exists, as it were, between the earth and the sun—as a thought exists between a subject and a proposition. It needs both, pointing down and pointing up; it “presupposes” earth and sun, as a thought presupposes subject and proposition. But does the thought (episode of thinking) bring with it any further existential implications? The plant also exists in a surrounding environment of physical objects and processes—does the thinking exist in a surrounding environment of objects and processes? If so, are these objects and processes logically implied by the thinking? In particular, is what we call the external world implied by the existence of thoughts? Is there a Cogito for the external world? The idea might seem incredible: how could a thought, an event of thinking, imply the existence of the external world? What about the evil demon and the brain in a vat? True, some philosophers have sought to deny that these scenarios are really possible—they have held that the content of thought requires the existence of suitable external objects in order to exist at all. Thus, we have “externalism” about the content of thought: what a person thinks is fixed by his or her actual environment and causal connections thereto. However, such views are not terribly plausible; in any case, I won’t discuss them. But I will discuss another line of argument that seeks to forge a logical link between mind and world—between the internal and the external. That is, I will defend the following Cogito: “I think, therefore the external world exists”; or, to parallel the traditional phraseology, “I think, therefore it is”—in Latin “Cogito, ergo est”. The “it” here is the physical world that exists outside the mind—the world of extended objects in space. We won’t get the entire external world as normally conceived, but we may get a part of it—and so derive from “I think” propositions concerning the existence of ordinary material objects. The first thing to notice is that thoughts (and other mental events) do in fact occur in an environment of physical objects, rather like plants; the question is whether this is an a priori necessary truth. Thus, thoughts occur in the vicinity of bodies and brains and interact with these objects, as a matter of actual fact; what we have to determine is whether this is built into the very identity of thoughts, a necessary condition of their existence (like subjects and propositions). Is it part of the nature of thoughts to be so situated? First, we can observe that thoughts have bodily effects: what you think affects what you do. And this is part of their identity: if you think it’s cold, you will dress warmly (given appropriate desires). If a thought did not have such consequences, it would not be thatthought. This is a familiar reflection. Of course, the thought might not actually have such consequences, but it is (as we say) disposed to have them (even if the brain of the thinker has been removed from the body, he still has a tendency to act in certain ways). The question is what this tells us about the thought itself: must it be somehow bodily? I think the answer is yes: the thought can have bodily effects only because it has a (partly) bodily nature. That is, the thought can only have a certain functional role vis-à-vis the body if it has a (partly) bodily nature. This nature will involve the brain; so, the thought has a cerebral nature of some sort. A materialist will say that its nature is wholly cerebral, but we need not commit ourselves to that, restricting ourselves to the weaker claim that it has a cerebral aspect. Accordingly, and in line with reasonable materialist sympathies, thoughts must have a physical nature of some sort (along with a possibly non-physical nature). But then we can deduce from the occurrence of a thought that something physical exists—that there exists something bodily that is built into the thought. This something is presumably complex and consists of elements that could exist without the thought existing (just like in the case of the brain), so we get the idea of a material world that can exist independently of anything mental. We get something like an atomic theory (bodies are made up of smaller physical components). Of course, we already know this to be true on empirical grounds, but now we see that it is deducible a priori from the very nature of thinking: if a thought exists, it must have a nature that allows it to affect the body (if there is one); but then it must have a bodily nature of its own; therefore, there must be something bodily in the world. Cogito, ergo est. I think, therefore there is an external world. Given that I know with certainty that an episode of thinking is occurring, and given that I know a priorithat this requires bodily existence of some sort, I can infer that a body exists in much the way I normally suppose. In fact, I can be certain of this—or as certain as I am that subjects and propositions exist given that thoughts do. I can infer a physical “environment” for acts of thinking much like the one I normally take for granted (centering on the brain). I can formulate a Cogito for the external world, or part of it.[1] Lichtenberg is thus multiply wrong in his claim that nothing follows from “I think” apart from the existence of thoughts. And Descartes is wrong that the Cogito argument applies only to the self; in fact, the conclusion is more robust in the case of the external world than in the case of the self, since only a vanishingly thin notion of self can be derived from “I think”. Descartes, of course, cannot avail himself of this argument for the external world given his dualism—for him the mind has no physical nature at all—but this dualism is hardly something we would wish to hang onto. A reasonable dose of materialism is all we need to develop a modified Cogito that delivers substantive conclusions about the make-up of the world: we can now assert that the world is partly mental and partly physical. The existence of physical things follows from the existence of mental things; it isn’t merely a contingent add-on. Thus, thoughts are rooted in selves, point to propositions, and incorporate their physical environment (the brain). They imply the existence of something psychological (a self), something abstract (a proposition), and something physical (a body); they are not logically cut off from the rest of reality. They affirm more than just their own existence (a la Lichtenberg) but extend outwards into three domains. The Cogito has been underestimated.[2]

[1] I won’t discuss how much of an inroad into skepticism this makes except to say, “Some but not much”.

[2] It has been overestimated in its original incarnation, as a proof of the existence of the self as commonsensically conceived; but it has been underestimated as a device for proving other existential propositions from apparently minimal resources. There is more in “I think” than meets the eye.

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Formulating the Cogito

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Formulating the Cogito

The Cogito is usually expressed in the words “I think, therefore I am”. The first clause is misleading: it suggests the proposition that I am a thinker, i.e., that I think things at different times. I might assert this because I remember thinking something yesterday and expect to think something five minutes from now. The sentence “I think” is like “I play tennis”—it suggests something I do regularly. But this cannot be what is meant because it is not indubitable: I could be wrong in my memory of past thinking and my expectation of future thinking. Rather, the sentence should be something like “I am thinking now”: that is something that is not vulnerable to skeptical doubt concerning other times. But then the conclusion has to be read accordingly: “therefore I exist now as a thinker”. This does not imply that I am also a self that desires, imagines, dreams, etc. I can only be having occurrent instances of part of my mind at any given time, not all of it; so, these occurrent instances are all I have to go on in deriving a conclusion about the existence of myself. I cannot say “I am thinking now, therefore I exist as a desiring, imagining, dreaming being”: the conclusion doesn’t follow from the premises. I can only move from what is happening in my mind now to an existential conclusion about an entity of that type. So, I can never infer anything about the existence of a self that transcends what is happening right now in my consciousness, i.e., a self that has many mental attributes not just the attribute currently instantiated. Consider “I am now doubting that I exist, therefore I exist”, one version of the Cogito. Strictly speaking, the conclusion must be read “therefore I now exist as a doubting being”. Whether I am any other type of psychological being has yet to be determined. Thus, this version of the Cogito delivers only the existence of a momentary doubting being—which is just a part of my nature as a self. I can’t even infer that I exist as a thinking being unless we add the premise that doubting is a form of thinking—and might it not be just a feeling of uncertainty? Certainly, the existence of a feeling being does not entail the existence of a thinking being. Also, being able to think one kind of thought does not entail being able to think all kinds of thought, so the version that begins “I am thinking now” doesn’t necessarily give us the existence of an entity that thinks the kinds of things we normally take ourselves to think; it might give us only a small fragment of our mental life as we normally understand it. Given the structure of the Cogito, it is capable only of yielding the most minimal notion of a self, not the multidimensional entity we take ourselves to be. Really, it should be formulated “I am thinking now, therefore I exist now as a momentary subject capable only of thinking what I am thinking now”—not much progress against the skeptic. It is hardly what I mean when I say “I exist”.

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Do I Know That I Exist?

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Do I Know That I Exist?

I am going to argue (a) that the Cogito cannot prove that I exist but (b) that it can prove that various other things exist. This is ironic given that it is commonly supposed that the Cogito can establish the existence of the self (person, subject) but that only the self’s existence permits of such a demonstration. Both these points are actually quite easy to establish, as it turns out. In order to know whether the Cogito can prove the existence of the self, we need to know what the self is. So: what am I? That is a philosophical question—a question of metaphysics—and there are several answers to it that have been proposed. These are: the self is an animal body; the self is a composite of a body and a mind; the self is just a mind (“conscious subject”) and nothing more; the self is a primitive entity that can be described both mentally and physically. It is clear that three of these views will not permit the deduction of the self from the premise “I think”. For we cannot deduce from that premise that a body exists: that is subject to Cartesian doubt and is not entailed by the mere existence of thought (but see below). Nor did Descartes suppose otherwise: he didn’t think he could deduce the existence of any extended substance, such as a human body, from the premise that he thinks. So, if any of these bodily views is correct, the Cogito is powerless to demonstrate the existence of the self so understood. No, what Descartes supposed is that the Cogito can prove the existence of the self as a purely mental thing (a “res cogitans”). So, what is this purely mental self? Clearly, it is the subject of mental attributes: not just the attribute of thinking but also of desiring, intending, imagining, feeling, believing, and anything else you think belongs to the mind. But how can “I think” establish the existence of a subject that does these other things? How can we assert anything like “I think, therefore a subject of desire exists?” Thinking doesn’t entail desiring (imagining, etc.)! All that I can infer from “I think” is that a certain part of me exists—the part that thinks. But that is not all that I am qua conscious subject, so this multifaceted self is not demonstrable via the Cogito. In order to prove the existence of that self we will need separate arguments corresponding to each mental attribute: e.g., “I desire, therefore the desiring part of me exists”. But this doesn’t prove the existence of a unitary self—the self I take myself to be. It just proves the existence of many subjects of consciousness corresponding to each mental attribute I possess. But that is not what I am, i.e., a unitary being—unless we take the view that the self is actually not unitary but merely an assemblage of separate parts. The trouble with that view is that it is false: that is not what I am. So, the reconstructed Cogito does not deliver the self that actually exists, but only some watered-down conglomerate. Strictly, it only delivers a small part of the self as normally conceived—the part that thinks. The Cogito should read “I think, therefore a thinking thing exists”—with no implications for the existence of a self that thinks and desires and imagines, etc. But that is obviously not what the self is as we normally understand it, a thing that merely thinks. This is a thin surrogate for that familiar self. In fact, I know quite well that I am a unitary self with a variety of mental attributes; it is just that this knowledge is not vouchsafed by the Cogito. Indeed, the correct conception of the self is along the lines of “a single unitary embodied conscious subject enduring over time”: but the existence of that self is certainly not demonstrated by the Cogito. So, the Cogito does not establish the existence of the self—as it really actually is. At best it gives only an aspect or part of the actual real self. If I know that that self exists–and surely, I do know this–it is not by means of the Cogito; it might well be by means of ordinary observation, internal and external. Descartes wanted a skepticism-proof demonstration of the existence of the self, but he devised no such thing; the lesson should be that there is no skepticism-proof demonstration of the existence of the self, not as it normally (and correctly) understood. However, the Cogito can be used to prove the existence of other things, arguably important and surprising things; and thus, it provides a way out of solipsism and the mere existence of thoughts. Some of these are obvious, but some are not. First, it proves that there are mental attributes, since thinking is a mental attribute. I am certain that I am thinking (“there is thinking”), and I am certain that thinking is a mental attribute, so I am certain there are mental attributes. I am also certain that thinking is not a physical attribute, given that thoughts are not extended and extension is the essence of the physical. I also know with certainty that I know these things, since I can see that they follow logically from “I think”. Furthermore, I know that at least one token thought exists, and not just the type thought; so, I know that my thinking exists in time (token events need time to occur in, unlike types). In addition, I know that concepts exist, since thoughts are made up of them: there is no such thing concept-free thought. I also know that propositions exist, since thinking is a propositional attitude; so, I know that concepts combine into propositions. All this is obvious and easily deducible, but it doesn’t stop there. Don’t I also know with certainty that my acts of thinking are caused, given that all events have a cause? And if I know that, don’t I also know that my thoughts are governed by laws, given that causation implies laws? Thus, I can put together what I know by introspection with what I know a priori and derive some moderately interesting results. Some of these results have existential implications such as the existence of events and laws: thinking consists of token events with causes and causes require the existence of laws to back them. And now we might see our way clear to more surprising deductions: for example, that my thoughts must have a physical substrate. For, if events of thinking are subject to causal laws, but there are no causal laws of thinking per se, then these events must fall under other laws, and these would have to be physical (Davidson’s argument). If we combine this argument with the “I think” of the Cogito, we reach the conclusion that I have a brain! My point here is not to endorse that argument but merely to illustrate that there is room to get beyond the mental world that is demonstrated by the Cogito. We might also construct an argument establishing that space must exist if thoughts do, because time requires space, or because it makes no sense to postulate a world of individuated concrete events outside of space. We can thus work out from the Cogito to more adventurous conclusions aided by suitable a priori principles.[1] The certain knowledge that I think can be made to yield results independent of the traditional Cogito, which is dubious for the reasons given above. This procedure may not be skepticism-proof but it may be sufficient to generate knowledge of matters that transcend the mere awareness of thinking. The general idea behind the Cogito was essentially sound, although the traditional move to the existence of the self doesn’t work. If so, both Descartes and Lichtenberg were wrong: we can’t get the self from “I think” but neither is it true that we can get nothing but the existence of thoughts.

[1] I am not saying that this is easily done, or even that it is ultimately possible; I am merely saying that it is part of the intellectual landscape and not to be dismissed out of hand. It is a project worth pursuing.

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