External Conditions of Thought

The idea of the singular proposition is that propositions can contain particulars as well as universals as their constituents. If I think that that bird is pretty, my thought’s content contains both a particular bird and the general property of being pretty. Thus a singular thought has conditions of identity and existence that depend on objective particulars—birds, cities, planets, other people, etc. No such particular, then no such thought; and thoughts are distinct in virtue of the distinct particulars they contain. It is not often remarked that the same thing is true of the properties that constitute the other half of the proposition (so to speak): they too supply the identity and existence conditions of the thought (or the meaning of the corresponding sentence). The property also sits inside the proposition, alongside its partner, the particular. Propositions offer hospitality to both sorts of entity.

Given this general picture, we can formulate a kind of transcendental argument for the existence of particulars, as follows. If we accept that singular thoughts exist, then the world must contain the particulars that form them—both those particulars in particular and also particulars as a category. That is, there is no possible world in which singular thoughts exist and particulars don’t. The particulars don’t have to be material objects or events but could also be mental particulars; so the transcendental argument doesn’t disprove idealism. What is required is just that some particulars exist—specifically those that form the singular propositions that constitute the content of singular thoughts (and meanings). We know, then, that the world cannot consist solely of universals. That would not follow if propositions were invariably general as to content; then those propositions could exist in the absence of particulars. If description theories of reference were true, perhaps accompanied by Russell’s analysis of descriptions, then the existence of particulars would not be a precondition for the existence of propositional contents; so the world could be void of particulars and those thoughts would still be available to be thought. This is a straight consequence of the theory of singular propositions: singular thought is impossible in the absence of particulars, so if there are singular thoughts there are particulars. The theory of thought thus implies a certain kind of metaphysics—one that accepts particulars as real. And it is certainly an interesting point that thought should be capable of having such metaphysical consequences. I might put it by saying that the distinctness of thoughts depends upon the distinctness of the particulars they concern.

            Interesting, but perhaps not startling. More startling, however, is the analogous thesis in respect of universals: that there is a similar transcendental argument proving that universals exist. For thoughts also have general content, carried by concepts corresponding to properties, and this content depends for its existence on the existence of the properties it concerns. Without those properties general thoughts would not be possible. Just as the mind cannot from within its own resources generate singular thoughts—it needs the contribution of objective particulars—so the mind cannot from within its own resources generate general concepts—it needs the contribution of objective universals. Since the proposition contains properties, it depends on properties for its existence; but then there are no thoughts in a world without universals. Thus a certain type of metaphysics is implied: reality must contain universals, in addition to particulars, which serve to make thought possible. It is hard to see how these universals could be creatures of the mind, inventions of some sort, because invention depends upon thought, and hence presupposes the existence of general propositional content. Nor could properties reduce to sets of particulars, on pain of making thoughts about properties into thoughts about sets. I don’t have all these particular things in mind when I think that a certain bird is pretty; I simply have the property of being pretty in mind.  [1] So we need to countenance a robust ontology of general properties (universals) given the nature of thought: no universals, no thoughts. Thus we can deduce ontology from psychology, world from mind.

            The root reason for this dependence lies in an essential feature of universals: their ability to bring things together. They allow for similarity among diverse particulars. If particulars spread universals around, by giving them multiple instantiations, then universals round particulars up, by determining their similarities. So the following thesis sounds plausible: General concepts need objective universals in order to provide the groupings that general thought delivers. The mind could not manufacture the groupings that record similarities without the aid of objective universals that constitute these similarities. Picture the mind trying to find similarities among particulars without appeal to the objective basis of similarities—it would flounder in the dark. No, it needs to latch onto the external objective grounds of similarity, viz. universals. You can’t think about the class of square things without representing the objective property of being square (or if you do you will need some other subsuming concept). So the basis of mental classification is grasp of the objective respects of similarity, i.e. properties or universals. The mind can’t just make this stuff up itself—it needs outside help. It needs objective universals as much as (or more than) it needs objective particulars. That is, singular propositions really do contain particular objects and general properties of them—and this presupposes a certain kind of ontology. You can’t separate semantics from metaphysics, meaning from reality, thinking from being. In this respect, there is no logical gulf between the subjective and the objective, the inner and outer. Metaphysics shapes psychology. The external world of objects and properties is the foundation of the internal world of individual concepts and general concepts. It is not possible to hold the world of thought constant while varying what reality contains in the way of ontological categories. This is the most general lesson of what has come to be called “externalism”. There cannot be a thinking mind without an objective world to mirror.  [2]

C

  [1] This raises the question of whether direct reference theory applies to thoughts explicitly about sets: can propositions contain sets of particulars as well as particulars? That would seem to involve overpopulating the content of thought with all the members of a given set. The alternative would be to suppose that thoughts about sets have descriptive content, as in “the set consisting of all F’s”: here the thought would contain a general concept applicable to a given set and not the set itself as a particular object. 

  [2] According to traditional “Fregean” thinking, there is no overlap between thought (meaning) and reality, since propositions do not contain anything that belongs to the world of reference (particulars and their properties). But according to direct reference theory propositions contain worldly entities, so there is an overlap between world and mind: the constituents of the one are also constituents of the other. Thus it is that we can deduce ontology from psychology (and vice versa). 

Existence and the Cogito

The Cogito strikes most people as intuitively valid, but it has been trenchantly criticized. How exactly the inference is supposed to work still excites controversy. Here I will consider a line of objection that I have not seen pressed before. The natural way to interpret the inference is that it moves from a premise about instantiation to a conclusion about existence: I know with certainty that I instantiate the property of thinking, so I must exist as the subject of this property. We might expand the argument as follows: “I have the property of thinking; if something has a property, that thing must exist; therefore I exist”. My thoughts exist (as I know with certainty), and they must be instantiated in some object; this object is not identical to my thoughts; so we can infer that there exists an object (viz. myself) that is not identical to my thoughts. Thus we can move nontrivially from the existence of thinking to the existence of a thing that thinks. But consider the analogous argument concerning unicorns: “Unicorns are horses with one horn, so unicorns instantiate the property of having a horn; but there has to be an object that instantiates this property; therefore unicorns exist.” Or: “Santa Claus has a beard, so he instantiates the property of having a beard; but then he must be an object that instantiates a property; therefore Santa Claus exists”. The premises seem true but the conclusion is false, so the argument must be invalid—but where does it go wrong? Meinong would give the following answer: it does not follow from the fact that an object instantiates a property that the object exists—it might only subsist. In more recent terminology, these objects might be merely “intentional objects” not real existent objects; and so instantiation does not imply existence on the part of the instantiating object. Applying this point to the Cogito, what is to rule out the possibility that the self is a merely intentional object that instantiates the property of thinking but does not exist? We can see that objects are able instantiate properties without thereby existing, so why can’t the self be one of those? To be sure, the properties exist—they are real entities all right—but it doesn’t follow that anything that instantiates them is itself real. Fictional objects are a counterexample: the property of being a detective is a real property, but the fact that Sherlock Holmes is a detective doesn’t make him real. Likewise, thinking is a real property that things can have, but it doesn’t follow that anything that instantiates this property is itself real—after all, Holmes also thinks. Maybe the self is like Holmes.

            How might we respond to this objection? One possibility would be to appeal to the certainty of the premise that I think, holding that this is what sets the Cogito apart. But am I not also certain that unicorns have one horn, that Santa Claus has a beard, and that Holmes is a detective? The fact that an object certainly instantiates a property does not automatically confer existence on that object (it is certain that the Golden Mountain is a mountain). Another possible way out would be to question the whole ontology of subsistent or intentional objects, insisting that there are no objects but existent ones. This flies in the face of the seemingly obvious fact that some things don’t exist and yet have properties; but also, from the point of view of the Cogito, it gives up the certainty of the inference—for now we have to accept that the validity of the Cogito depends on the rejection of Meinongian metaphysics. Maybe we should, maybe we shouldn’t, but we don’t want the fate of the Cogito to be tied to that metaphysical issue. No one hearing the Cogito for the first time thinks, “Well, it depends on your view of Meinong”. Descartes surely did not take a stand against Meinong-style ontology when he enunciated the Cogito. The validity of the argument should not depend on whether or not you entertain Meinongian predilections. It isn’t as if those with such predilections are prohibited from accepting the Cogito; at any rate, that’s not the way the question presents itself.

            A third suggestion is that there is an asymmetry between unicorns (etc.) and thinking selves, namely that you can hallucinate unicorns but you can’t hallucinate thinking selves. Thus it can seem to you as if there is a unicorn in front of you without there being one, but you can’t hallucinate having thoughts without actually having them. That asymmetry must be conceded—beliefs in unicorns are not epistemically necessary but beliefs in thoughts are—but it doesn’t help to salvage the argument: for all we get from this is that the existence of thoughtsis certain, not that the existence of thinking selves is. True, we can be certain that thoughts exist, but we could still be in error about the existence of a self that has them. There might be nothing except thoughts in the vicinity. We might be under an illusion about the self, as we might be under an illusion about unicorns. We might be misinterpreting a collection of thoughts as a self that has them. Compare seeing a swarm of bees in the distance and mistakenly thinking there is a single big organism there. Maybe we hallucinate a unitary self when we introspectively encounter a swarm of thoughts. Who knows what might be going on? We can’t hallucinate the thoughts, but we could be under an illusion about what they signify, i.e. an underlying unitary self. Similarly, when we hallucinate a unicorn we are not hallucinating its component properties—they are real enough qua properties (though their present instantiation is illusory). Anyway, even if it is somehow impossible to hallucinate a self, why should the existence of a self be entailed by the existence of individual thoughts? We still haven’t justified the step from the existence of thoughts to the existence of a thing that has them (the Gassendi-Lichtenberg objection).

            Fourth, we might hope to find something in the specific nature of thought that guarantees an existent thinker, where this something is not present for properties in general. Maybe having a single horn doesn’t prove the existence of what has the horn, but thought might be such as to necessitate an underlying existent thinker. This would be the analogue of the ontological argument: most properties indeed fail to guarantee existence, but the property of total perfection does guarantee it, because of its specific nature. Instantiation by that property entails the existence of the instantiating object (according to the ontological argument). There has been a strong intuition (notably voiced by Frege) that mental states necessarily require a bearer—something that has them, a subject. But it is far from clear how this can help the Cogito: Meinong could agree with this point while insisting that the bearer is a merely subsistent entity. Fictional mental states logically require a bearer too, viz. a fictional character, but they lack existence. The notion of a subject of predication—an object of instantiation—is too weak to deliver the conclusion of the Cogito: we might be predicating thought of a non-existent object. But also: does the intuition hold for all kinds of mental states or only thoughts? And does it apply to unconscious mental states as well as conscious ones? Is it true of the bodily sensations of jellyfish or worms? And is the point any different from the claim that any kind of state needs something for it to be a state of, including the state of being electrically charged or the state of the weather? We really need an argument, analogous to the ontological argument, showing that thinking inherently and uniquely calls for an existent subject that can be the reference of “I”, but what this argument might be remains elusive. Could it be that the capacity to think requires the capacity for the self-attribution of thoughts, and hence for a self? But what could establish that, and how would it guarantee the reality of the self in question? Descartes never argued anything of the kind, and it would certainly undermine his claim that the Cogito is primitively compelling. So there is nothing comparable to the ontological argument showing that it is in the nature of thought to bring with it an existent bearer, let alone one with the characteristics of the self as normally understood.  [1]

            But perhaps there is an intuition lurking in this unsuccessful argument that might have more cogency: namely that there is a contradiction in the idea of existent thoughts occurring in a non-existent object. Fictional thoughts can occur in a fictional object, but non-fictional thoughts require a non-fictional object. Thoughts are particulars not universals (token not types) and existent particulars need existent objects to inhere in. Properties can exist and be properties of non-existent objects, but events and processes can’t both exist and also inhere in non-existent objects. What would it mean for Sherlock Holmes the fictional character to have an existent real thought? Wouldn’t that make him real? So there is a metaphysical assumption at the heart of the Cogito: those thoughts whose existence is evident to us must exist in a being that is itself existent, since real events need real objects as bearer. Real mental particulars need real mental substances to inhere in—they can’t exist in an unreal substance. In Meinong’s language, existent events cannot inhere in merely subsistent objects. If there is real thinking going on, then this requires a real entity to do the thinking; and we know for sure that real thinking is going on—hence we know for sure that we exist. If the thinking was fictional, the subject of it would or might be fictional too; but granted that the thinking is not fictional, neither can he thinker be. Thus I know that I am not a character in fiction (or a “logical fiction” or an hallucination). Compare the bodily counterpart to the Cogito: “I have a body, therefore I exist”. We could not object to this that the premise could be true and the conclusion false, because the body, not being fictional, cannot be had by something fictional: something must non-fictionally exist if my body non-fictionally exists (whether it is the reference of “I” is a further question). We can infer from the existence of the body that something exists. To be more precise, if I know that I have bodily states, then I know that something exists in which those states occur—for example, if I digest there must exist something that digests. The inference is solid because it is compelling to claim that physical states require a physical bearer—a physical thing that has them. If I know there are physical states, then I can deduce that there are physical objects, because states must be states of something. And it would be absurd to suggest that existent physical states could exist in a non-existent object—a merely intentional object. If Holmes is in real physical states, then he must be real himself—fictional characters can’t have real indigestion! The difference from the classic Cogito is just that the premise here is not certain (not an epistemic necessity): I don’t know for certain that I am in physical states or even that I have a body. So this is no use for Descartes’s purposes, though the connection between premise and conclusion is the same in both cases, viz. a metaphysical principle precluding unreal bearers of real states. As we might put it: we can’t mix the existent with the subsistent, the real with the imaginary, the factual with the fictional.

            Where does this leave the Cogito? It allows it to struggle on, to retain a semblance of cogency, but it leaves it vulnerable to skeptical doubt. Descartes was working with a scholastic metaphysics of substance and accident—his evil demon was not supposed to call that into question. Against this background the Cogito is relatively smooth sailing. But a dogged opponent might protest that this metaphysics is not immune to doubt, and if it is doubted the Cogito will not go through. Why should we accept that there are substances at all, material or immaterial—why not make do with an ontology of states, events, and processes? Later philosophers indeed did advocate such a low-calorie ontology (e.g. Russell) and so there is no substance in the world for thoughts to inhere in anyway. Thoughts may form sets or aggregates, according to this point of view, thereby gaining a sort of collective unity, but they don’t inhere in substances. So there is no valid metaphysical principle licensing the move from the existence of states to the existence of substances that support them. That may be wrong as a piece of metaphysics, but in the context of the Cogito it would need to be addressed.

More subtly, however, there is this problem: the prima facie persuasiveness of the Cogito seems not to be hostage to the kind of principle I have invoked to bolster it. Is this what someone is thinking who accepts the Cogito? Possibly, but it would have to be in some subliminal or tacit manner, since the requisite principle is hardly laid bare in the usual presentations of the Cogito. It takes work to come up with it and it is not entirely self-evident, even if you accept it. So it is not clear it can explain the felt cogency of the Cogito; indeed, it renders it much more wobbly than we might initially have supposed. Once it is fully articulated in this way its appearance of self-evidence starts to fade, and yet it is routinely hailed as the surest of philosophical theses. The resourceful Meinongian has produced a new threat to the Cogito, and the suggested repair to the argument lacks transparent cogency, even if it is ultimately correct as a piece of metaphysics. So we are left in a rather unsatisfactory position: the argument is not clearly valid but not clearly invalid either. I would say that it can be salvaged more effectively than might have seemed possible once the Meinongian objection has been formulated; for that objection looks formidable at first sight and it takes some ingenuity to forestall it. Hume’s kind of critique of the self, which takes the self as a type of fiction (at least on some interpretations of Hume), was evidently alien to Descartes and quite inimical to the Cogito(we can’t deduce the existence of a substantial self merely from the existence of ideas encountered internally). And yet it is hard to deny that the Cogito has all the appearance of self-evidence, whatever its final analysis may turn out to be.  [2] This philosophical gem thus remains as tantalizing as ever.

  [1] Not that the ontological argument is really any good in the end, but it is at least an argument that needs to be contended with.

  [2] What we are entitled to assert on the basis of the Cogito is that the certain existence of thoughts proves the certain existence of something that has them. That is, thoughts need a bearer because they must be instantiated by something other than themselves; but this bearer could be anything, even a non-existent fictional entity. Call this the weak Cogito: it doesn’t deliver a substantial self with the intuitive characteristics of the self, and is quite compatible with a Humean view of the self, but at least it shows that there is something that can’t be doubted (in addition to the existence of thoughts themselves). If we employ a particular quantifier shorn of existential import, we can say that the weak Cogito allows us to assert the following proposition: “I think, therefore there is something that thinks”—where the quantifier can range over even purely intentional objects that lack existence, or any kind of existent object, physical or non-physical. The strong Cogito, by contrast, asserts that we can prove that a substantial existing conscious self underlies the existence of thoughts (there is also room for intermediate strengths).

Distinctions and Differences

There is distinction in the world and distinction in the mind: things differ and so do concepts. States of affairs differ and thoughts about them differ. But how are these distinctions related? Are they dependent or independent? Clearly there can be objective distinctions that are not mirrored by cognitive distinctions—where thought fails to capture distinctions in reality (consider reality before the onset of thought). But can there be distinctions in thought that are not mirrored by distinctions in reality? Of course, distinctions in thought are real distinctions, but the question is whether distinctions in thought always reflect distinctions in what thought is about. Can two thoughts be distinct even if what they are about is not distinct? Can thoughts differ while the states of affairs they represent are identical?

            The orthodox view is that they can, but on closer analysis this is wrong. It is generally agreed that in the vast majority of cases cognitive distinctions are matched by objective distinctions—it isn’t that reality is a homogeneous lump that we insist in thinking about in different ways—but it is supposed that there is a special subclass of cases in which no worldly distinction can be found that corresponds to a cognitive distinction. I speak, of course, of classic sense-reference cases: the reference is the same but the sense differs. But this is confused thinking: identity of reference does not entail identity of state of affairs expressed, because of the different properties that can be connoted by a singular term. The name “Hesperus” connotes the property of being the evening star while the name “Phosphorous” connotes the property of bring the morning star—and morning and evening are not the same thing. Appearing in the evening is a different worldly state of affairs from appearing in the morning. Similarly for “water is H2O”: here the word “water” connotes the property of appearing in a certain way to human subjects while “H2O” does not; the way water looks is a different property from the property of having a certain molecular structure. In these kinds of cases the cognitive difference is not independent of distinctions in the world; it corresponds precisely to such distinctions. No cognitive difference without objective difference. The content of thought cannot vary without the subject matter of the thought varying, i.e. without a distinction at the level of objective reality.

            This is as it should be: for what would be the point of conceptual distinctions that fail to map onto worldly distinctions? The aim of concepts is to make discriminations among things beyond the mind (sometimes within the mind): a distinction between concepts that concern exactly the same objects and properties is a pointless distinction—why distinguish what is not distinct? Our minds track distinctions in reality; they don’t invent distinctions that don’t exist in reality. Internal distinctions without external differences are not real distinctions. Do not multiply distinctions beyond necessity! That is, thought should track only objective distinctions, of which there are many and subtle. There is more than enough fine structure in the world to occupy the discriminating thinker; anything else is redundant and pointless. Indeed impossible: concepts can’t differ without the aid of distinct states of affairs–that is their nature (this is a variant of Brentano’s thesis). A distinct concept is always a concept ofsomething itself distinct. Externalism about conceptual distinctions is true: no concept is distinct but reality makes it so. Distinctions supervene on differences.

            You might think that concepts could differ in their dispositional properties while corresponding to identical states of affairs, thus counting as distinct concepts. But (a) the same concept could have different dispositions in different cognitive beings as a result of their different cognitive architecture, and (b) such dispositions would be pointless as means of discrimination. What is the point of discriminating what cannot be discriminated? You might say that different beings could have different needs with respect to the same objective world, so they might differ in how they conceptualize external things; but then the different states of affairs involve states of the organism itself—their varying needs ground the distinction in the concepts. The concept edible may apply to the same thing for one creature as inedible does for another, but that is only because of different properties of the different creature’s digestive systems (the concept is relational). Concepts differ only in virtue of objective differences that they represent or correlate with—there is no separate dimension of variation capable of individuating concepts. This is not to say that connotation reduces to denotation, still less that connotation doesn’t exist; it is just to say that connotation always cashes out as objective worldly difference—since what is connoted is always a property of things. Even in the case of semantic tone (dog versus cur) there is always an underlying distinction at the level of facts: different emotions are aroused by the different concepts. There are no conceptual differences that are “purely cognitive”, that exist independently of non-conceptual facts. The world is the ultimate dictator of conceptual distinctions. Conceptual distinctions are never “in the head”.  [1]

            The right picture is this: the world consists of the totality of objective distinctions—different ways that things can be. The aim of thought is to latch onto and exploit these distinctions, and it has nothing to work with other than the distinctions that exist in reality. Thoughts divide up according to the states of affairs that form their content. It is certainly not that concepts acquire their distinctness from some source other than objective reality and then foist this distinctness onto reality whether it likes it or not. There is nothing to constitute a difference of concepts other than distinctness in what they represent—objects and properties,

  [1] In the case of indexical expressions we always have differences in spatiotemporal context that correspond to different indexical concepts, as with “here” and “there” and “now” and “then”. But this is a complex subject I won’t pursue here.

Differentiation and Integration

According to standard embryology, the process of ontogenesis is characterized by organic differentiation. From an initially homogeneous collection of cells tissues of various kinds are formed. This is no doubt powered by genetic instructions from within the original uniform cells. Maturation is thus a transformation from sameness to diversity as tissues develop in the body according to a fixed schedule. The end result is an organism composed of many organs each equipped with a characteristic type of cell and associated physiology—heart, lungs, bones, kidneys, etc. As differentiation occurs there is a need for coordination between the new types of tissue and the organs that tissue serves, and the adult organism clearly contains components that need to be integrated into a functioning whole. Thus there is no differentiation without integration (and vice versa). These are the twin pillars of biological development: genetically driven diversification and concomitant integration of the elements thereby generated.

            This basic picture can be applied to language development. Initially there are just undifferentiated cooing sounds existing alongside the inarticulate sounds of crying, but these soon come to be replaced by language-like sounds (consonants and vowels) without structural complexity. These in turn are replaced by one-word sentences (“dada”, “milk”) that display the rudiments of language. Only later do these come to be combined into two-word strings, and subsequently into the full range of syntactic and semantic categories. The details don’t matter for present purposes: what concerns us is that language development follows a pattern of differentiation analogous to that undergone by the body.  [1] A relatively formless initial state is gradually transformed into a highly structured system of elements that combine together. Anatomy develops by differentiation, but so does grammar. When the initial unstructured sentences are transformed into noun phrases and verb phrases there has been a process of differentiation comparable to the formation of heart and lungs (or the internal anatomy of each). This is not surprising once we accept that language is itself a biological phenomenon—an aspect of the human organism. And it makes logical sense: you derive an intricately structured organism from unstructured beginnings by a process of differentiation (it would be difficult to implement such differentiation in the sperm and egg). Language doesn’t emerge fully formed in the child but matures in the brain by a process of increasing structure and complexity. It grows by splitting into different functional units—that must nevertheless be integrated if they are to achieve their purpose. We are accustomed to the idea that language is a system built for integration—producing sentences by combinations of words—but we must also recognize that it is a system that arises by differentiation from something more primitive.  [2] It was once a growing thing in the child and only reaches stasis after a lengthy sequence of differentiating stages—just like other human organs. Language is a product of gradual ontogenesis, which only later achieves its full combinatorial power. The adult language faculty enables integration ad infinitum, but at one time it was without much in the way of internal structure (relatively speaking). So let us add to the productive power of language its origins in a simpler form of living tissue. Grammar is the form that linguistic differentiation takes in human ontogenesis—just like anatomy and physiology. Linguistic differentiation is biologically at one with histological differentiation. Language thus follows the same basic pattern of organic growth. How else could the architecture of language arise?

            But if this is true of language, isn’t it also true of the mind more generally? The various components (“organs”) of the mind must be integrated in order to function as a unity, but first they had to develop by some sort of maturational process. Perception, cognition, emotion, will—all need to emerge as distinct systems during ontogenesis, to be integrated later (or pari passu). But what was the initial state? Some may speak darkly of a blank state, but that would need to be supplemented by an account of how such a state could be progressively differentiated. Something has to turn into the various faculties of mind—some state of the pre-natal brain. About this process we know little to nothing, yet it must be so in some way. What is the analogue to the one word sentence or those even more primitive cooing sounds? And how did concepts emerge by differentiation? They were not present fully formed in the fetus’s brain but arose by a maturational process to become the vast combinatorial system we now deploy with such consummate ease. Presumably they arose by a process of differentiation: from William James’ “blooming, buzzing confusion” (whatever that means) to an articulated array of combinable elements. This maturational differentiation must be genetically driven, like other biological growth, but it results in a psychological faculty far removed from the initial state of the organism. Again, we know little to nothing about how this works, but we have good grounds for supposing a distinct path of differentiation and integration. One can certainly imagine that unstructured thoughts might with time transform into thoughts with a subject-predicate structure—and thence into more complex forms. First there were feature-placing thoughts (the mental counterpart of “It’s raining”) and later they turned into structured thoughts (along the lines of “There is heavy rain in London now”). Conceptual differentiation created the panoply of concepts we now take for granted.

            Coordinating conceptual differentiation and integration is a highly non-trivial task, as it is in the case of the body and language. Once you have the plurality you need to keep it under control. The brain is the ringmaster here. Grammar is encoded in the brain and it sets the rules for combining words; in the case of concepts something analogous must be true—rules that combine concepts in certain acceptable ways (not just arbitrary lists or jumbles). So differentiation combined with integration requires rules or principles of coordination. The heart must be coordinated with the lungs to produce satisfactory aerobic performance; similarly concepts must be coordinated in the right way to produce intelligible thoughts. Integration doesn’t happen by magic. The more differentiation there is the greater the demands of integration. An organism with very simple thoughts doesn’t need much apparatus to keep its thoughts on track, but an organism like us relies on mechanisms that prevent thoughts from forming defectively or randomly. In aphasia these mechanisms can fail, leaving words to fail to link up correctly; in principle the same thing could happen to thoughts—concepts fail to link up to form coherent thoughts. It is surprising that more breakdowns of this kind don’t occur.  [3] If there is a language of thought, there ought to be aphasia in that language if the brain is suitably damaged, which produces aphasic thought. The differentiation and integration of concepts will be tied to linguistic differentiation and integration in the language of thought.       

            The innate language faculty thus has two basic properties: (a) it permits unbounded productivity in its mature form, and (b) it enables a stupendous feat of differentiation as it guides the maturation of language in the child’s brain. It is as creative in the latter respect as in the former (though it doesn’t get as much credit for the latter). The adult lexicon is the product of maturational differentiation (how, we don’t know); sentence production is the outcome of integration rules. Both are built into the genetic blueprint for language. Nor does differentiation cease at normal linguistic maturity, since we continue to make linguistic and conceptual distinctions. The differentiation machine doesn’t go completely offline, its job done; it allows us to make ever-finer distinctions that aid thought. So it isn’t that one kind of creativity completely ends to be replaced by another; we are still able creatively to generate distinctions (though it doesn’t come as naturally as during childhood). Distinction making is as crucial to language development as the growth of the ability to combine existing elements. So I propose conceiving of the language faculty (and the conceptual faculty) as a union of differentiation and integration: it allows the combination of pre-formed elements, to be sure, but it also generates those elements by a (mysterious) process of differentiation. When abnormalities arrest language development we see in sharper outline the maturational stages speakers go through—we see how the differentiation process can be blocked (the same is true of human bodily growth). As adults we tend to forget this early history, but it is as essential to our mastery of language as the growth of the heart is to our survival. The language faculty is as much a creative product as it is a creative producer.

            I said that differentiation and integration are the basic laws of biology (so far as concerns ontogenesis), but they are also relevant to evolutionary change. For what is species evolution but biological differentiation? Natural selection causes species differentiation (along with other factors), though mechanically not by pre-set program. There is no predetermined evolutionary schedule like the maturational schedule. Thus simpler forms evolve into more complex forms, splitting off to make a new kind of biological entity. Phylogeny recapitulates ontogeny. However, there is no real analogue to integration, since the different species don’t operate together to form a larger whole. True, it used to be thought that this might be so, as if each species had its functional role in the super-entity called Nature (“the biosphere”); but these days we tend to think that the entities that have arisen by evolutionary differentiation are independent entities subject to no coordinating principles. They are not like organs in a body or words in a language. There is no “grammar of nature”.  The evolution of species is differentiation withoutintegration.  [4]

  [1] This point of view is defended by Eric Lenneberg in Biological Foundations of Language (1967), esp. Chapter Seven.

  [2] This is in no way incompatible with the nativist account of language acquisition: the genetic instructions for generating full-fledged language are present at birth, but that is consistent with the existence of a maturational schedule that involves cellular and cognitive differentiation. Similarly, instructions for building a heart at a certain maturational stage are present at birth, but it takes time for the actual organ to be constructed by a process of differentiation. Nouns and verbs emerge at a certain maturational stage (the second year of life), but the program for making them was written in the genes.  

  [3] Drunkenness can cause breakdowns of motor coordination analogous to earlier stages of motor development (a kind of regression), including speech difficulties; but it doesn’t appear that drunkenness can derail the performance of the language of thought—we keep thinking coherently as we stagger and trip, slur and mumble.

  [4] Suppose there was a symbiotic parasite that entered the brains of host species and conferred language on the host—the parasite contains grammar. The parasite might instigate a series of maturational stages of language development in the host just like those of humans. It is functioning as an organ of the host’s body/mind—much as symbiosis in general has this character. This would provide a sense in which different species might operate as a unity.