I am tired of hearing people say, as if it were uncontroversial, that they are “Humeans” about laws and causation, where they mean to defend the “regularity theory”. That was not Hume’s view, as has been amply demonstrated. They are claiming the authority of a great philosopher for a position he did not hold (in fact, I know of no great philosopher who held this view). What they are following is Ayer’s version of Hume not the real Hume. So they should declare themselves not Humeans but positivists. But that doesn’t sound so laudable since the fall of positivism. They should at least acknowledge that many people reject this version of Hume as well as the doctrine falsely attributed to him.

 

 

 

Can There Be Subjective Facts?

 

 

I invite you, intrepid reader, to accompany me on a journey into the heart of darkness—into a region of utter obscurity. It will test us both, but it should be worth the effort, including the bouts of sickness and insanity. No, it won’t be that bad—just a bit of a headache and some mild nausea.[1]For I propose that we explore the question of whether reality could include facts that can only be grasped subjectively. By that last phrase I mean grasp that depends on occupying a particular point of view. The background is familiar from bats and blind people and alien forms of consciousness: we can’t grasp what it’s like to be a bat because we don’t share bat experience (we don’t occupy the bat’s “point of view”) and blind people can’t grasp the nature of color experience because they don’t have color experience (they don’t occupy the “point of view” of color perceivers). Some facts (properties, meanings) can be grasped without oneself instantiating them—for example, being an elephant or being a dodecahedron—but others (allegedly) can’t be grasped without being an instance of them oneself. You can’t know what it is like to see red without seeing red yourself, though there is no difficulty about knowing what a mountain is without oneself being a mountain. This suggests that there are subjective facts—facts that can only be grasped subjectively, i.e. from a specific point of view, i.e. by instantiating those facts oneself. It suggests that it is in the natureof certain facts that they can be apprehended only by beings equipped with specific types of experience, viz. those they are endeavoring to apprehend. Such facts might be called “intrinsically subjective”. By contrast, there are other facts that are “intrinsically objective”, i.e. they have a nature that allows them to be grasped from many points of view (or from nowhere). Thus some facts are subjective and some are objective, and this classification is written into them, part of their essence. The facts dictate the conditions of their being known (grasped, apprehended). My question is whether this is the right way to look at the matter.

Facts about consciousness are supposed the primary kind of subjective fact. If we define consciousness as consisting of the realm of facts there is something it is like to obtain, then we can say that facts about what states of consciousness are likeare subjective facts, i.e. they can only be grasped by sharing them. It will be convenient to introduce some abbreviations here, so let us call facts about what it is like “W-L facts” and let us call knowledge that depends on sharing the facts in question “S-I knowledge” (short for “self-instantiation-dependent knowledge”). Then we can say that W-L facts are intrinsically known in an S-I manner: that is, we can only grasp facts about what an experience is like by ourselves having experiences of that phenomenological type. In brief: W-L entails S-I. This is a move from the metaphysical to the epistemological: it is built into the nature of the facts (metaphysical) that they are grasped or known subjectively (epistemological). This thesis figures in an argument against materialism: mental facts can’t be physical facts because the former are S-I while the latter are not, i.e. the former are subjective while the latter are objective (understood in the epistemic way defined).[2]One response to this argument is to maintain that so-called objective facts are not as objective as you might think; in fact, they are subjective. This is because what we call the “physical” really consists of facts about consciousness, though consciousness of a primitive and alien type (I am talking about panpsychism and its spiritual cousins). The thought is that the problem of emergence can be solved by supposing that matter is shot through with mind, perhaps ismind at a fundamental level. That certainly looks like a promising strategy: straddle the mind-body gulf by edging the body in the direction of the mind. Mind arises from mind—not so inconceivable a feat. The point I want to make about this sort of approach is that it sharpens a more fundamental problem about consciousness, viz. how it is that consciousness has being at all. If reality consists of consciousness, and consciousness is W-L, and W-L requires S-I, then reality is intrinsically such as to be knowable only from a specific point of view. If the basic mental level of reality consisted of elementary consciousness of the type exemplified by bats, then only beings equipped with this type of consciousness could grasp the nature of reality. Reality would be intrinsically subjective in the sense that only certain types of being could have an adequate conception of it—and that could be a small subclass of the class of all possible knowing beings. Reality would (could) exist only forthis privileged class of being—for everyone else it would be strictly inconceivable. The question is whether that is intelligible: could reality consist of such essentially subjective facts, partially or totally? Could there be facts that could onlybe grasped from a particular point of view? Could there be facts that rule out any objective conception? Specifically, could W-L facts rule out a non-S-I mode of conception? In yet other words, could facts about consciousness resist any attempt to include them in an “absolute conception” of reality? Are they inconceivable objectively? My thesis will be that this is wrong—such facts cannot be intrinsically subjective. Facts about consciousness are not necessarilygrasped subjectively: even W-L facts must be graspable objectively. To put the point as strongly as possible, everythingabout consciousness must be conceivable objectively—and this is a fundamental metaphysical truth. There cannot, as a matter of metaphysical necessity, be purely subjective facts. There can be purely subjective conceptions, and we might well be confined to conceiving consciousness in this subjective way, but no fact(property, states of affairs) can be subjective in the intended sense. It is a category mistake to describe facts as subjective of objective; those appellations belong only to conceptions of facts—thoughts, representations, or ideas. The subjective-objective distinction is an epistemic distinction not an ontological one. But this leaves us in a very precarious position with respect to our understanding of what consciousness is, as will emerge.

First, let us note that experiences admit of several types of objective characterization drawn from within our current conceptual scheme. We can bring conscious experiences under causal descriptions (“the cause of this”, “the effect of that”), and we can express their relations with physical facts (such as correlated brain states). It is also possible to characterize them in abstract structural terms as well as mathematical terms (as in psychophysics). There is more to a conscious experience than what it is like for the subject: we can conceive such states in many different ways. The hard question is whether the W-L aspect can in principle be conceived in a way that doesn’t depend on sharing the point of view implicit in it. Is there a way of conceiving it that is available to beings that do not themselves instantiate the property in question? We naturally think of God here, but that raises questions it would be best to avoid (Does God instantiate all points of view? What is his knowledge like anyway?). One possibility is that this property exists but is completely ineffable (recall my warning about dark obscurity at the beginning): there are objective W-L facts, but no being could ever conceive them. All beings must conceive these facts subjectively or not conceive them at all: if the latter, then reality contains ineffable ingredients. A less alarming position is that possible beings might be able to grasp W-L facts without reliance on their own point of view: they might be able to form a conception that captures these facts and yet is independent of how they view things.[3]For example, they might be able to forge structural descriptions that encapsulate the facts and yet can be grasped by anyone whether they instantiate these facts or not. Then the nature of the facts would not dictateadopting a subjective conception of them; an objective conception would be available too. Of course, we find it hard to understand what such a conception would look like, given our own concept-forming faculties, but the general idea is intelligible enough—other beings (or us in the future) might be able to conceptualize consciousness in ways that transcend our current self-centered subjective conceptions. Then reality would not contain properties that can only be conceived subjectively; it would not be populated by properties that inherently favor one way of viewing the world over another.

Here it is important to make a distinction between two ways in which a fact might resist being conceived objectively. We have the modal truth: Necessarily it is impossible for us (fully) to conceive consciousness otherwise than subjectively. That truth might, however, have two possible sources: it might stem from the very nature of the fact in question—itdecides how it can be known; or it might be that ourfacultiesrestrict us to subjective conceptions—not the facts themselves. And we must not assume that just because we can’t conceive of W-L properties in objective terms that it is in the nature of those propertiesthat this is so—the reason might stem from our own cognitive make-up. Wenecessarily can’t conceive them in any other way, but theyimpose no restrictions on how they can be conceived; it is how we interact with them not what they are in themselves that gives rise to the necessity. It seemsto us that it is in the nature of color experiences to preclude a blind man from grasping them, but it may be that the difficulty arises rather from our distinctive human way of forming concepts of experience. Perhaps the blind man in other types of cognitive being has no trouble conceiving of experiences that he happens to lack. What is a necessary truth for us need not be true for everybody; in particular, it may not be the property itself that is the source of the problem. Thus the facts in question can be grasped objectively as a matter of principle even though we can never so grasp them. Then we would not have to admit that reality contains facts that are intrinsically tied to a specific point of view.

The general point here is that the terms “subjective” and “objective” are not descriptive of facts themselves but of ways of conceiving facts: no facts are subjective or objective considered in themselves. Physical facts can be conceived subjectively or objectively, relatively or absolutely, and the same is true of mental facts. If we are confined to subjective conceptions of mental states, that is a truth about us not about them: “subjective fact” is an oxymoron, unless it means “fact we happen to know about subjectively”. So consciousness exists neutrally between subjective and objective, despite our bias in conceiving it towards the subjective. But that means that we don’t grasp the manner of its existence: how we conceive it doesn’t tell us how it exists in reality, as an objective conception of it would. Thus we have an inadequate grasp of consciousness—in an important sense we don’t know what it is. What it is would be revealed from an objective standpoint, but that standpoint is inaccessible to us; we are limited to a standpoint that gives at best a partial conception of it. So we don’t understand what the existence of consciousness amounts to—what it isfor it to exist. That is the really hard problem: trying to figure out what we are talking about—trying to arrive at an adequate conception of consciousness itself. Even if we could solve the problem of emergence, say by invoking panpsychism, we would still be left with the more fundamental problem of discovering what the existence of consciousness really consists in. Granted, we know somethingabout consciousness, but we don’t know the most vital and basic thing—what its mode of existence is. We only grasp its existence-for-us not its existence tout court. It must, as a matter of metaphysical necessity, have an existence apart from our subjective mode of conceiving it, but we are blocked from discovering what this objective existence amounts to; at any rate, we presently have no conception of what it might be. This means, of course, that we don’t grasp the nature of our ownexperiences, let alone the bat’s, since they too must have an existence quaexperiences that is accessible from all points of view. We don’t grasp what it is like to be us(as that would be represented in an objective conception of what it is like to be us).

I have drawn a sharp line between two concepts: the concept of what an experience is like and the concept of a subjective conception. The former does not entail the latter: what it is like pertains to the nature of consciousness (its metaphysics) while the subjectivity of a conception pertains to how we think of a certain subject matter (epistemology). It is a substantive claim that the metaphysical property requires a subjective conception; and I have disputed this, suggesting instead that all facts must be accessible to an objective conception, even if not one of which we are capable. This logical point is lost if we carelessly use the world “subjective” to refer to a feature of consciousness itself andto the way we tend to conceive of it (by using our own case as model). Consciousness cannot be necessarilyconceivable only via a subjective conception, i.e. one that relies on self-instantiation, because that is an unintelligible idea of what reality is like. To repeat, reality cannot be relative to a particular point of view—only conceptions of reality can be. Facts are just facts: how we conceive them is another matter. This means that idealism cannot be restricted to how we now think of the mental: if the world is really the mind, then mental facts can’t be limited by the ways we generally conceive of them. Mental reality would have to be conceived objectively not subjectively, because its existence must be independent of the point of view a given type of creature brings to it. We may not be capable of acquiring the concepts needed to make sense of the objective existence of mental reality. At any rate, mental facts must have a nature that goes beyond what is contained in our present subjective conceptions. Those conceptions cannot even reveal what it is like to be a bat, though that latter fact is something that must be accessible in principle to different points of view. There must be a way of conceiving bat experiences that is accessible to beings that lack such experiences, on pain of making reality point-of-view-dependent. In other words, it is only a contingent fact that bat experiences can only be grasped by beings that share those experiences. There are no inherently subjective facts; subjectivity is in the eye of the beholder (which is not to say it is unreal).[4]

 

Colin McGinn

 

 

 

 

[1]Note to American readers: tongue is in cheek here.

[2]This argument is presented in Thomas Nagel’s “What is it like to be a Bat?” (1972), as is the general notion of subjective and objective I am working with.

[3]Nagel discusses the possibility (necessity) of objective descriptions of mental facts in The View From Nowhere(1986), chapter II.

[4]Of course there are subjective facts in other senses of the word: there are facts about conscious subjects, mental facts, facts about personal opinions.

 

What the Mind Does: Internalization and Externalization

 

 

The concepts of internalization and externalization are found with some frequency in psychology. It is said that the child internalizes the surrounding culture, including moral and social norms (the same can be said of an adult transplanted into a hitherto alien culture). It is also said that the child internalizes the rules of grammar of the language he or she grows up to speak. In clinical psychology we hear that a person has internalized family conflicts or role models or patterns of response. On the other hand, psychoanalysts have suggested that people externalize their own psychological traits, as with classic projection; and it can be added that animism and anthropomorphism are instances of the same phenomenon. Linguists speak of public communicative language as the externalization of an (innate) internal language system.[1]Art and technology are sometimes held to be externalizations of the mind. These are certainly suggestive ways of talking, but what do they really mean? How literally should they be taken? Can they be elevated into a general theory of the mind?

As always the dictionary provides a useful starting point. The OEDgives us this for “internalize”: “make (attitudes or behavior) part of one’s nature by learning or unconscious assimilation; acquire knowledge of (the rules of language)”. For “externalize” we have: “give external existence or form to; project (a mental image or process) onto a figure outside oneself”.  Merriam-Webster has: “to make external or externally manifest”. The idea of internalization is that something originally external to the mind is rendered part of the natureof what is internal to the mind: it was “out there” and now it is “in here”, shaping it, forming its inner architecture. Thus what was once merely the code of one’s society becomes one’s own inner code—a sort of cultural invasion has occurred (often unconsciously).  The language spoken by others is incorporated into one’s own symbolic faculty, made internal. The mind is evidently capable of this internalization operation, converting what is perceived externally into a feature of one’s interior landscape. In the case of externalization the governing idea is that what is originally inner is expressed outwardly: the external comes to have the formof the internal—it is the internal made manifest. The nature of the external thus reflects the nature of the internal. Evidently the mind is capable of this feat of externalization, converting mind into world, inner into outer. The internal is made external, as the external can be made internal. The mind pushes outward as it also pulls inward. Notice that this is not the same concept as the concept of causation: it is not merely that the external can cause the internal and the internal can cause the external; rather, the external can determine the nature of the internal and the internal can leave its imprint on the external. We might say that there is in both cases an “internal relation” between the inner and the outer: each side reflects the other. A sort of isomorphism obtains, as well as a kind of dependence. This is a strong relation, in which the mind is said to literally internalizewhat lies outside its boundaries, as well as literally to externalizewhat is within it. Clearly an exceptionally tight and intimate relationship is envisaged, a kind of overlapping of internal and external.

It might be wondered whether others parts of nature can be said to internalize and externalize. The idea is not preposterous; indeed, the term “internalize” is used in biology to describe the cell pulling external material across its membrane and into its interior (“endocytosis”). The justification for using this term is obviously that a boundary exists across which certain items flow, so changing the nature of the entity they flow into. There is the internal landscape of the cell and there is its external environment, and the latter can penetrate the former, molding it in the process. I suppose we could extend the use of the term to feeding: the external in the form of food is taken in and converted into tissues of the body, shaping them—though here the idea of changing the nature of the body seems strained. But the abstract notion of an entity with boundaries being shaped by and shaping its environment, by dint of a transfer of elements, seems generally applicable. Even in physics and chemistry we could justify talking this way, though to my knowledge physicists and chemists don’t: the atom absorbs and expels energy, internalizing and externalizing a transferable ingredient; heat is absorbed into a system altering its behavior, also seeping out to alter the surrounding world; osmosis is the passage of molecules from inside a physical system to outside it (and vice versa). There is what is internal to an entity and what is external to it; and the activity of the entity, in conjunction with its environment, involves various kinds of internalization and externalization. We might, indeed, contrive a metaphysical system from this basic structure: The world is the totality of internalizations and externalizations. There are these entities called “monads” and they operate by internalizing what is around them and externalizing what is within them. They are not isolated atoms but essentially interacting entities whose nature is fixed by acts of internalization and externalization. There is a dialectic between internalization and externalization that defines the ontological structure of reality. We might even conjoin this metaphysical picture with panpsychism: the psychic units that constitute so-called physical reality internalize what exists around them and they also externalize themselves in the form of perceptible matter. The metaphysical possibilities are endless: history is the externalization of the internalized; God internalizes everything and his creation is the externalization of his nature; mind is matter internalized and matter is mind externalized…

Putting that metaphysical flurry aside, we can focus on the mind and its capacity to engage in both sorts of operation. Clearly we must assume some sort of boundary in order to make sense of the concepts of internalization and externalization. The external must lie on the further side of this boundary in order to be capable of crossing it from elsewhere. The mind must be bounded by something or else there would be nothing external to it. This boundary could be conceived in many ways, depending on further ontological commitments: it might just be the boundary of the brain or the body, or it might be conceived immaterially. A dualist would suppose that the immaterial substance could internalize extended substance by that substance crossing an immaterial boundary—not presumably by actual spatial transfer but by some sort of extraction of form. Similarly, the mental substance could externalize itself by imparting its form to material substance: but not by itself becomingmaterial. In the case of language the talk of externalization is motivated by the idea that both the internal language and its outer expression share their grammatical structure (and maybe lexicon), so that we can say that the internal structure is manifested in the structure of outer speech. Thus outer public language has a derivative structure determined by copying the original structure of the internal language (perhaps supplemented by other sources of structure). Likewise, if we thought that inner speech were the internalization of outer speech, we would suppose that the derivation goes the other way. On either view we have an isomorphism of grammatical structure. We don’t tend to think this way about knowledge in general, as if all knowledge is a kind of internalization of the outer—as if knowledge of the universe were the internalization of the universe. We internalize the rules of English, say, but we don’t internalize the planets (those rocky entities). But that may be a reflection of a misguided internalist view of the mind: wouldn’t an externalist say that (some) mental states are (partly) individuated by objects in the environment, so that it is acceptable to say that the mind internalizes the external world? On earth we internalize water (H2O) in our thoughts and meanings, while on twin earth we internalize retaw (XYZ). So we could in principle extend the idea of knowledge-as-internalization to the full range of knowledge, not just knowledge of language or cultural norms. We internalize objects and facts as well as rules and attitudes.[2]

Similarly for externalization: why should we not extend the idea of externalization further than is customary? Why not view all behavior as the externalization of the mind? An action is an intention externalized. Art and artifacts count as externalizations, so what about the actions that lead to them? The notion of expressionencourages this thought: we express our emotions in our body, and this expression is surely a form of externalization (consider facial expressions). There is a natural “fit” between inner feeling and its bodily expression, not merely a causal connection. Just as perception can be viewed as the internalization of objects, so action can be viewed as the externalization of desires (etc.). The mind takes in and it also gives out. It isn’t just that reasons causeactions; actions externalizereasons—embody them, lend them material form (consider a chess move). And it isn’t just that objects cause perceptions; perceptions internalize objects. The relation is a lot more intimate and internal than we have tended to suppose—not logical perhaps, but certainly structural.[3]Maybe it is a general property of mind to be an internalizing externalizer. The mind absorbs things across its boundary and it extrudes things in the opposite direction. For instance, the mind internalizes the rules of grammar to achieve mastery of a particular language, but this mastery is externalized in actual speech. In the case of innate knowledge of the universal rules of grammar, there is no such internalization, since the knowledge is present ab initio; but there is still externalization as the internal language faculty hooks up with sensorimotor systems. It is natural to suppose that there exists an innate internal mental apparatus prior to any internalization of the environment, and that this apparatus interacts with the environment to lead to internalized knowledge; this composite system then interlocks with sensorimotor systems to make externalization possible—spoken language and maybe action in general (as well as art and technology). We have a transition from the internal to the internalized to the externalized. There are internal and external domains and there are operations that cross these boundaries, thus producing mixed domains of the internalized and the externalized. Not everything in the internal domain is internalized (we are not empiricists) and not everything in the external domain is externalized (we are not idealists): but there is a good deal of internalized and externalized stuff in the world—intersections of the internal and the external mediated by the operations of internalization and externalization.

People speak of stimulus-response psychology and of computational psychology to characterize a general conception of how the mind works and what it does; we can likewise speak of internalization-externalization psychology (or I-E psychology) to capture the general conception of how the mind works we are exploring. This is quite a specific conception, incorporating as it does the idea that the mind is a device forinternalization and externalization—not for mediating stimulus and response or for performing computations (though these ideas need not be regarded as simply false, just incomplete). It depicts the mind in a particular way—not just as an input-output device, but as something that performs a characteristic kind of operation of conversion. Not that the conversion operations in question are well understood or free of mystery; indeed, they are quite puzzling. For how is it possible to internalize the external or to externalize the internal? Isn’t this contradictory? It seems like a peculiar form of mental alchemy—yet it is evidently what happens. Nor can we draw comfort from those non-psychological analogues I mentioned earlier, because abstract similarity is not identity of mechanism: howthe mind contrives to internalize and externalize is left unexplained. It is not just a matter of absorbing molecules across a membrane or emitting energy from an atom; these are specifically psychological processes—a sort of mimicry, perhaps, whereby the outer is converted to the inner and the inner is converted to the outer. It is not like inserting a marble into a box or ejecting a marble from a box, in which the ideas of internalization and externalization have literal spatial meaning; but it is not entirely unlike that either. It is as ifthe external world is inserted into the mind, or extruded from it. People speak of the extended mind; well, this is the externalized mind. Similarly, we can speak of the “internalized world” to capture the power of the mind to bring the world into its domain (the world extends beyond its own natural boundaries to take up residence in minds). The mind protrudes into the world in acts of externalization, but the world also protrudes into the mind in acts of internalization. Each visits the other’s territory, leaving its distinctive mark. That is the essence of the mental—internalizing and externalizing, crossing an interface.

Let me illustrate how this conceptual framework applies by considering two unrelated topics: music and sense. Music is closely associated with the emotions, and this gives it a unique place in the operations of internalization and externalization. On the one hand, music is easily internalized, as if it is designed to be: we hear a tune with our outer ear and instantly it enters our inner musical landscape. Its emotional resonance plays a role in this ready internalization. On the other hand, audible music expresses inner feeling perfectly, so lending itself to the externalization of emotion—in the form of dancing, singing, playing an instrument, humming, etc. We internalize tunes and we externalize what is thus internalized. And there is an especially intimate connection between the internal and the external in the case of music: we repeat the external tune silently in our head, and we externalize our inner experience in forms that precisely mirror what is going on internally (notably when singing). The psychology of music is thus steeped in internalization and externalization, and would hardly be conceivable without them. In the case of sense, Frege supposed that senses are objective external entities, but he also supposed that they shape the very nature of thoughts: we internalize senses in such a way that they enter our cognitive landscape (the same could not be said of references as Frege conceived them). At the same time grasp of sense is externalized in public symbolic systems—these systems make sense manifest. So senses are both internalized and externalized—and this is essential to their identity, what they are. If we think of senses as existing in our environment (in some extended sense), then the task of thought is to internalize them; but once internalized they are available for externalization in language, so that language becomes sense externalized. That is the psychology of sense: first internalization, then externalization—internal absorption and external expression. And that is psychology generally: internalizing the world and then externalizing what has been made internal. It isn’t just that an outer stimulus elicits an overt response via an internal process, or that information flows from the environment into the brain and then out to behavior. Rather, the mind possesses a specific set of capacities that we call “internalization” and “externalization”; and these capacities deserve the names they have been given. If we want a single word to express this general conception, analogous to “behaviorism” and “computationalism”, we might choose “conversionism” for want of anything better.[4]

 

Colin McGinn

 

 

[1]This is the position taken by Chomsky: the primary instantiation of language is as an internal system connected initially to thought; only later is language hooked up to sensorimotor systems that produce a spoken communicative language. When that happens the internal system is externalized, i.e. its properties are transferred to an outer capacity. Outer language has structure becauseinner language has structure—the former is derivative from the latter. See Why Only Us, Robert C. Berwick and Noam Chomsky (MIT Press, 2016).

[2]I don’t say we should endorse this proposal, only that it is worth considering. An alternative would be to divide all knowledge into two classes: internalized knowledge and non-internalized knowledge. Then we could have debates about where given types of knowledge fall—what about knowledge of mathematics or ethics? Similarly, there will be a division between externalized facts about the world and non-externalized facts (which are presumably much more numerous, if we keep God out of it).

[3]One approach would be that perception involves building a mental modelof the perceived object, thus replicating its structure internally. Or we might go full externalist and insert the object itself into perceptual content, expanding the mind into physical space. And there are other approaches too that could be used to justify the word “internalize”.

[4]I suppose we could try for something catchy like “int-ext psychology” or “outside-in theory”, but it might be best to stick with the more cumbersome description.

 

 

Against Causal Epistemology

 

 

It has been suggested that knowledge of the natural world enjoys a causal foundation not enjoyed elsewhere. Thus such knowledge is deemed intelligible while other kinds are not. Accordingly, we can accept a notion of robust truth in relation to propositions about the natural world while other kinds of proposition must remain under suspicion of non-truth. Empirical science emerges as both true and knowable while mathematics and morals make dubious claims to truth and knowledge.[1]It would be mysterious how we can have knowledge in the latter two cases, given that their subject matter doesn’t causally interact with our cognitive faculties. We must therefore seek some sort of non-cognitive account of those areas, accepting that knowledge is impossible as far as they are concerned.

I propose to question this bifurcation at its root: causal epistemology is a misguided idea, applicable nowhere; it therefore provides no standard whereby we can judge other domains of thought and discourse. It isn’t just that causal epistemology isn’t generally required for respectability and intelligibility though it delivers those virtues in the case of some domains. Rather, there is really no such thing anywhere—it is a chimerical ideal. These are subversive claims given a longstanding orthodoxy, but they serve to undermine subversion in areas that matter to us.

The idea of causal epistemology includes a picture and a promise. No one supposes that we currently possess a complete causal account (explanation, science) of human knowledge acquisition in the case of our knowledge of the natural world, but the idea of such an account is supposed to make us feel safe about human knowledge in the areas to which it applies (though not in others)—it provides a reassuring picture of what is going on. The promise is that this picture will be converted into a full-blown causal theory of how knowledge is acquired, which will vindicate such knowledge. The world makes a causal impact on our sense organs via physical stimuli (light, sound, pressure, chemical diffusion) and as a result we form beliefs about the world outside our skin. Empirical knowledge is an effectof physical stimuli; the causal relation puts us in “contact” with the world beyond, mediating between mind and reality. For example, I know that there is a cup on my desk because the cup on my desk is causing me to believe it is there: it is operating causally on my senses and my nervous system transmits this operation to my belief centers. Thus the connection between belief and fact is rendered intelligible; thanks to causation we canknow such things. Moreover, this causal connection can be investigated by the empirical sciences, thus “naturalizing” such knowledge. By contrast, nothing like this is possible with respect to putative knowledge of mathematics and morals: numbers, sets, and moral values don’t causally impinge on us, generating the kind of “contact” required for knowledge. Such knowledge would be altogether mysterious and unintelligible; and so the truth status of mathematical and moral claims is brought into question.

But the picture and the promise are precisely that—they are programmatic. Moreover, they are deeply mistaken about how empirical knowledge works. First we must make an important distinction—between the existenceof a causal relation between belief and fact, on the one hand, and our having knowledgeof such a relation, on the other. There is all the difference in the world between the cup’s causing me to believe in its presence and my thinkingthat this is so. This bears on the question of what my reasonfor belief is: is it that I seem to see a cup or is that I think that a cup is causing me to seem to see it? The latter suggestion is problematic: I don’t normally have such thoughts (I may even reject them); they presuppose the very item of knowledge they are supposed to ground (that there is a cup on my desk); and it is obscure how they can be explained in the favored causal terms—for how can the existence of a causal connection between a part of the world and my mind itself be a cause of a belief of mine? How does causation produce knowledge of causation, and how does the mind register psychophysical causation? No: the reason I have for forming my belief about the cup is simply that I have an experience as of a cup—not that I have an experience as of a cup causing me to believe in it (whatever that might mean). I have various sensory experiences as of the world being a certain way, and they function as my reasons for forming beliefs about how the world is. The concept of causation does not enter my deliberations or the reasons that figure in them. If there are such causal relations, they are not part of my reasoning process. My belief is justified to the extent that I have good reasons of this sort, but these reasons don’t advert to causal relations between mind and world.

This raises a natural question: does it matterwhether such relations exist so far as knowledge is concerned? Granted they do, but what is the relevance of that to epistemology as a normative enterprise? Here is a quick way to see the problem: suppose we abrogate the normal causal relations that (we believe) obtain between natural facts and our beliefs about them, replacing them with some other sort of relation—does that abolish knowledge? Suppose we postulate a pre-established harmony between belief and fact, superintended by God or Nature, with no causal interaction between mind and world, but exhibiting reliable counterfactual-supporting connections. By hypothesis there is no causal epistemology applicable to beliefs formed in this world, yet it is hard to deny that knowledge can exist in it: people have reasons based on their experience and there is a reliable link to truth. What if our world islike this (as Leibniz thought): does that mean no empirical knowledge is possible? Hardly. The ingredients necessary and sufficient for knowledge are present; it is just that there is no causal dependence between world and mind. The existence of causal dependence is thus extraneous to knowledge. What if physics abandons the notion of causality (as some have claimed it should): does that mean knowledge also undergoes defenestration? Rational reasons for belief would still exist in the shape of sensory evidence, despite the absence of causal relations.

We should also note that causation by itself is never sufficient for knowledge and has nothing intrinsically to do with knowledge. The world is constantly impinging on our bodies, but it doesn’t generally produce knowledge thereby. Most of the time we don’t even notice it. And certainly causal interaction between inanimate objects has no tendency to produce knowledge in them. Epistemology is normative, but causality is not. Reasons are not merely effects. Nor is it true that a belief is simply triggered by an outside stimulus; belief acquisition operates against a background of other beliefs that are normatively relevant (“holism”)–it is not just stimulus-response psychology. Then there is the old problem of deviant causal chains. Suppose there exists an opaque barrier interposed between me and the cup preventing any light from it reaching my eyes, but by some strange quirk of nature the cup releases a chemical that enters my skin and causes me to hallucinate a cup (I know nothing about this). We have here a causal dependence between my belief and the cup—but do I knowthere is a cup in front of me? I don’t seethe cup despite the causal connection, and it is doubtful that I have perceptual knowledge in this situation (why, is an interesting question). It can’t be just any old causal connection that leads to the kind of cognitive “contact” deemed essential to knowledge. Then too there is the question, bequeathed to us by Hume, of whether causation itself is intelligible: do we really know what causation is? Causation involves necessary connection, but isn’t that epistemologically problematic? Is knowledge of causation a secure foundation for epistemology? What if we can’t really know causation as it exists in objects? What if causation is itself a mystery? The causal theorist is remarkably sanguine about the epistemology of causation. Maybe all we are entitled to is the notion of contingent correlation, so that any attempt to invoke full-blooded causation is a mistake. It is certainly not a notion free of puzzlement.

And there are the notorious difficulties concerning inferential knowledge. Not all of empirical knowledge is of singular facts that we can observe by means of the senses; some things we must infer. But these things are not the causes of our beliefs, so the causal theorist must resort to an indirect way of extending the causal theory in their direction (consider knowledge of the future). Knowledge of generalizations is particularly problematic, since general facts don’t impinge on our senses (e.g., laws of nature). Really the causal theory applies at best to a small subclass of knowledge claims—those that concern directly perceptible particulars. The rest get consigned to hand waving. The case of introspective knowledge is instructive: we don’t sense our own mental states yet we know about them. So we can’t apply our (rudimentary) causal understanding of sense perception to introspective knowledge: my pain doesn’t transmit physical signals to a special sense organ that enables me to perceive it. Whether the causal account of knowledge can be extended to introspective knowledge is a moot question; yet it is hard to deny that the mind makes “contact” with its own inner states. Knowledge of what I am now thinking hardly fits the supposed paradigm of perceptual knowledge: isn’t it just a straight counterexample to such a theory of knowledge in general?

The upshot of these considerations is that a causal theory of knowledge hardly sets the standard for respectable epistemology. It is really just a vague picture of the mind linking itself to reality. This is not how knowledge works generally, and even in the cases most favorable to it there are serious problems. So it can’t be a point of criticism of some putative area of knowledge that it fails to live up to the high standards demanded by causal epistemology. So what if mathematics and morals fail to conform to the causal model? That model is defective even in the areas it is designed to cover. It is just massively tendentious to demand that other kinds of knowledge imitate this supposedly perspicuous model. Knowledge comes in many forms, covering many subject matters, and each form obeys its own distinctive principles and methods—perceptual, introspective, inferential, general, innate, logical, mathematical, modal, moral, aesthetic, political, historical, psychological, etc.[2]Reference is much the same, and it would be equally misguided to insist that all reference conform to the case of reference to a perceptible particular. Maybe it is hard to devise a theory of reference suitable for all types of reference—and similarly for all types of knowledge—but that is no reason to deny that reference and knowledge have wide (and univocal) application. Equally, it may be that these concepts give rise to genuine mysteries, but again that is no reason to deny that they apply to the real world. We should not seek to deform (or reform) our ordinary understanding of a region of thought or discourse in an effort to squeeze that region into the causal model, given the problems inherent in that model (“theory” is too grand a word). We shouldn’t try to revise the semantics of a piece of discourse just because we can’t see how to subsume it under a causal model derived from another piece of discourse. Knowledge varies with the subject matter and is as heterogeneous as it is.

 

Colin McGinn

[1]This issue is raised by Paul Benacerraf in “Mathematical Truth” (1972).

[2]This pluralist position is advocated by T.M. Scanlon in Being Realistic About Reasons(2014).