Jerry Fodor
Jerry Alan Fodor | |
|---|---|
| Era | 20th-century philosophy |
| Region | Western Philosophers |
| School | analytic philosophy , rationalism, cognitivism,functionalism |
Main interests | philosophy of mind, philosophy of language,cognitive science |
Notable ideas | modularity of mind |
Jerry Alan Fodor (born 1935) is a philosopher at Rutgers University, New Jersey. Fodor is a major proponent of functionalism and opponent of inferential role semantics.
He is the author of many groundbreaking books in the fields of philosophy of mind and cognitive science, where he laid the groundwork for the modularity of mind and the language of thought thesis. Fodor is also well known for his arguments against reductionism.
Fodor and the nature of mental states
In his book Propositional Attitudes (1978), Fodor presented one of the fundamental conceptual bases of his thought: the idea that mental states consist in relations between individuals and mental representations. Despite the changes which have characterized some of his theoretical positions over the years, the idea that intentional attitudes are relational has remained unchanged from its first formulations up to the present time. [1]
In that article, he attempts to show how mental representations (specifically sentences in the language of thought or LOT) are necessary in order to explain the relational nature of mental states. Fodor takes into consideration two alternative hypotheses: one which denies the relational character of mental states and one which considers mental states to be two-place relations (either between individuals and sentences of natural languages or between individuals and abstract propositions). Fodor's own option emerges out of the contrast of these two positions. His idea is that in order to properly account for the nature of intentional attitudes, it is necessary to employ a three-place relation (between individuals, representations and propositional contents) founded on a concept of mental representation.
The hypothesis of fusion
Given that Fodor accepts the relational nature of intentional attitudes, his first step is to try to clear the field of those who deny such a nature. Some authors, in fact, sustain the position (which Fodor calls the hypothesis of fusion) for which intentional attitudes are really "monadic" mental states. According to this view, "Simon believes that the Morning Star is Venus" expresses a mental state characterized by an individual "Simon" and a unary predicate "believes-that-the-Morning-Star-is-Venus" in which the verb is semantically fused with the object of belief. Fodor presents several arguments, of which I will cite just two, against this thesis:
1) There are a very large number of sentences of the form a believes complement. If all these sentences are atomic, how could human beings possibly learn English? (Fodor attributes this to Davidson, 1965).
2) Different propositional attitudes frequently converge on the same content: e.g., one can both fear and believe that it will rain on Tuesday. But, according to the fusion thesis, except for the reference to John, "John fears that it will rain on Tuesday" has nothing in common with "John believes that it will rain on Tuesday." In particular, the fact that the form of the words "it will rain on Tuesday" occurs in both sentences is just an accident. [2]
The Carnapian view
Fodor concludes that this position is "hopeless." But it remains for Fodor to deal with the second, and more common, position of intentional attitude attributions as two-place relations. Fodor further subdivides this alternative into two separate theses. The first, attributed to Rudolf Carnap, considers mental states as relations between individuals and sentences of natural language; the second, attributed to Gottlob Frege, considers the relation to be between individuals and propositions.
The position expressed by Carnap in Meaning and Necessity, taken up by Hartry Field in 1978 [3]and Gilbert Harman in 1982, [4]is interesting because it seeks to maintain the intuition that mental states are relational, without the necessity of any ontological commitment with respect to such conceptually troublesome entities as mental representations. [5]Fodor presents several arguments which he believes justifies its rejection. First, he suggests that Carnap’s theory is fundamentally behavioristic. Carnap, that is, has one theory regarding the objects of intentional attitudes and a second theory regarding the character of the relation of individuals with such objects. The second theory is behavioristic because, for Carnap, "to believe such and such is to be disposed ...in specifiable conditions... to proffer occurrences of the correspondent of the sentences which attribute beliefs. But, patently, beliefs are not behavioural dispositions and, a fortiori, are not dispositions to proffer anything." In simpler terms, since behaviourism is presumably false, then there must be something wrong in some part of Carnap’s explanation of propositional attitudes.
But Fodor also has some more interesting and persuasive criticisms to level at the Carnapian view. His second argument is to the effect that Carnap’s theory can most naturally be read as a theory which considers the type-identity of the correspondents of sentences which attribute beliefs as necessary and sufficient conditions for the type-identity of the beliefs actually attributed since Carnap was primarily concerned with the opacity of beliefs. His approach, therefore, was based on a strategy of inheriting the opacity of beliefs from the opacity of citations. The problem is that this strategy fails in every case in which the identity conditions of beliefs are different from the identity conditions for sentences. For example, it is likely that the sentences "Phil believes that Alice shot Fred" and "Phil believes that Alice was shot by Fred" attribute type-identical beliefs. But they are clearly not type-identical sentences. Fodor points out that a way around this problem would be to admit that objects of belief are, essentially, systems of translations of sentences. But this results in circularity. One way of characterizing the relation of translation between sentences is by reference to the communicative intentions of speakers-hearers. But we cannot then "identify the translations in reference to the intentions while, simultaneously, individuating the propositional attitudes (including intentions) in reference to the translations. Along the same lines, one can believe that it is raining without being able to speak English. This implies, once again, that objects of belief must be systems of translation and we end up in something like the circle described above.
Fodor’s solution is to abandon the idea that propositional attitudes are relations between individuals and sentences of natural languages while not abandoning the idea that they are relations between individuals and sentences tout court. He proposes that the relation is between individuals and internal sentences, or systems of mental representations.
The view of Frege
But before proposing his own alternative, Fodor still needs to deal with the second relational hypothesis mentioned above: that of Frege, which consists in the idea that intentional attitudes are relations between individuals and objective and abstract propositions. Such propositions, according to Frege, are completely independent from codification in either mental representations or in the representations of natural language. The anti-psychologism which underlies this position is well known: according to Frege, in fact, it is necessary to distinguish the thought which constitutes the sense ("Sinn") of a sentence from its representation in the mind of the speaker. As he writes in Über Sinn und Bedeutung (1892), mental representations are subjective:
- "The same representation is not always tied to the same sense, even in the same person. The representation is subjective, varying from person to person….. A painter, a coachman and a zoologist will probably connect very different representations to the name "Bucefalus." The representation essentially distinguishes itself from the sense of a sign. The sense can be common possession of many people and it not a part or mode of the individual psyche. It is impossible to deny that humanity has a common patrimony of thoughts which are transmitted from generation to generation." [6]
The fact that thoughts are not representations, nevertheless, does not mean that they have a nature similar to objects in the external world. In order to account for the peculiarity of their nature, it is necessary to appeal to a "third realm" outside of both the mental and the physical. But this leaves open the epistemological problem of how it is possible for an individual human mind to gain access to such abstract objects of the third realm. As Fodor puts it:
- "The main reason for which one simply cannot say 'propositional attitudes are relations with propositions. Period' is that I don’t understand it. I don’t see how it is possible for an organism to be in relation (in an epistemically interesting way) with a proposition except through standing in a (causal/functional) relation with some occurrence of a formula which expresses the proposition. Plato maintains that there is a special intellectual faculty with which one can look at abstract objects. Frege says that we grasp (that which I call) propositions, but I have not found any theory which explains what it means to "grasp" a proposition, other than the observation (in Frege, 1918) that it is not a perception of the senses because its objects are abstract and it is not introspection because its objects are not mental. (Frege also says that grasping a proposition is not the same as grasping a hammer. Obviously not.) [7]
The difficulty illustrated by Fodor is of both an empirical and a conceptual nature. What is at issue is the question of the psychological plausibility of theories: the point, in other words, is that it doesn’t seem possible to determine the nature of mental content only in the abstract, without taking into consideration the conditions which render that content empirically plausible (specifying, for example, how a physical system must be constituted in order for it to be able to instantiate them). Given this empirical limit to conceptual speculation, that which is necessary is some mechanism capable of elaborating mental content. The contact with hypothetical entities of the third realm by way of an unspecified technique of grasping seems to exclude this possibility for Fodor.
Fodor's solution
The difficulties left open by the problem of grasping disappear immediately, according to Fodor, as soon as one brings in the notion of mental representation. Following the standard version, for example, to think of Mary is to be in relation with an internal representation (with an idea) of Mary. But to adhere to this version does not mean, however, that rather than Mary, it is the mental representation that is thought of; to be in relation with the idea of Mary, in other words, does not exclude the possibility of being in relation with Mary, the person. Considering mental states to be triadic relations, representational realism makes it possible, according to Fodor, to hold together all of the elements necessary to the solution of the problem, putting an end to the questions generated by the alternative conceptions. Mental representations, moreover, are not only the immediate objects of beliefs, but also constitute the domain over which mental processes operate. From this perspective, they can be considered the ideal conjunctive link between the formal/syntactic conception of content and the computational conception of the functional architecture which represents, according to Fodor, our best explanation of mental processes.
The functional architecture of the mind
Fodor's well-known nativism, or belief in the innateness of many cognitive functions and concepts, emerges—following along the general path plowed by the linguistics of Noam Chomsky—from the criticism of behaviourism and associationism. His criticisms of these views led him to the formulation (or re-formulation) of the hypothesis of the modularity of the mind. Two properties of modularity in particular, informational encapsulation and the specificity of domains, make it possible to tie together the questions of functional architecture with the theme of mental content: the capacity to elaborate information independently from the background beliefs of individuals allows Fodor to hypothesize a mechanism capable of accounting for an atomistic conception of mental content.
Fodor and Chomsky
Fodor maintains that Chomsky’s criticism of language learning must be extended to cover all of the essential aspects of thought. In his The Language of Thought of 1975, Fodor presented his famous "impossibility thesis" with regard to the gradual acquisition of concepts. Suppose that you are a child in the first stage of such a process of acquisition and you must try to learn the concept X, a concept of the second stage. If something is a second-stage concept, then it cannot be coextensive with any first-stage concept, otherwise there would be no distinction in expressive power between the first and the second stages and no basis at all for such a hierarchy of learning stages. But if you are child who cannot represent the extension of a second-stage concept in terms of the extension of some first-stage concept with which you are already familiar, then you cannot represent the extension of that second-stage concept X at all because the first-stage concepts are all that you have at your disposition. And if you cannot represent the extension of the concept, then you cannot learn the concept because the learning of a concept implies the projection and confirmation of the biconditionals which determine that the extension of the concept has been learned. The conclusion is that either higher-stage concepts are indeed representable in terms of (reducible to) lower-stage concepts (in which case there is no basis for the distinctions between stages and the hierarchy crumbles with no actual learning taking place) or there are concepts in the higher-level stages which cannot be represented in the lower-stages, in which case the child cannot learn them. Fodor’s conclusion is that an "extreme innatism" concerning concepts is necessary to explain learning. He will accept, for example, that the complex concept AIRPLANE may be composed out of simpler concepts such as FLYING and MACHINE. But he insists that the human mind is "richly endowed" with many fairly complex concepts such as Machine from birth. This view has been strongly contested. [8]
In The Modularity of Mind, Fodor makes another crucial distinction between his approach to the mental and that of Chomsky. He attributes to Chomsky (and other so-called neo-Cartesians) the view that what are actually innate are (only) the intentional objects of propositional attitudes: the content expressed by the sentences of the language of thought. This, however, flies in the face of Chomsky’s own writings which have always tended to emphasize the existence of organs of the mind similar in structure and function to the modules talked about by Fodor. In any case, Fodor suggests, in this work, that his approach, unlike the others, attempts to explain what is required, other than content, to give rise to behaviour:
- "If you say '19' when I say '7 plus 12, please', your reply could undoubtedly be explained in part in reference to your knowledge of numbers. But this is not enough, given that, after all, knowledge does not translate into behaviour in virtue of only the content of propositions. It seems evident that mechanisms are needed which put into action that which is known, mechanisms which have the function of making the organization of behaviour conform to the propositional structures which are known." [9]
The connection between functional architecture and content is therefore required in order to explain one of the most relevant questions of the program of naturalization of the mental and the explanation of behaviour in causal terms.
Why modularity matters
Fodor thinks that a (moderately) modular view of the structure of the mind is necessary to explain the strong degree of autonomy from the central system that certain properties of perception demonstrate. He cites the case of experiments which demonstrate the specificity of domain of the mechanisms which act during the analysis of phonetic information. These experiments apparently demonstrate that the mechanisms of phonetic analysis are exclusively sensible to acoustic sequences of spoken language. But, according to Fodor, what really distinguishes modules from central processes is what he calls informational encapsulation. This is roughly the thesis that modules are much less open and permeable to background knowledge and beliefs on the part of the individual. Fodor uses the persistence of perceptual illusions to illustrate his thesis. Illusions, such as Müller-Lyer tend to persist long after a subject has been exposed to them and has learned that the two lines are, in fact, equal in length. The knowledge that the two lines are equal is cognitively available and constitutes part of his background knowledge which he can access consciously at any time. Nevertheless, when looking at the rods, one still effectively sees them as uneven and the illusion persists. This suggests to Fodor that basic perceptual modules are partly closed off from the cognitive background knowledge of the subject: modules are informationally encapsulated. The study of perception is of fundamental importance for illustrating the connection between functional architecture and the theory of mental content. The fact that perception exhibits characteristics of autonomy and independence from central processes (and that it is relatively impenetrable to background knowledge) can be posted at the base of a theoretical conception able to mediate between internalist conceptions (hence preserving representational realism) and externalist conceptions (hence allowing for a causal-informational conception) of mental content.
Fodor’s proposal is characterized by the attempt to converge the causal conception with the inferential thesis of perception. His goal is to break the bond between the inferential thesis and the thesis of the dependence of perception on the system of beliefs/desires of individuals. Basing itself on the importance of background knowledge in perceptual processes, the inferential conception has been utilized in favour of the epistemic hypothesis of perception. This hypothesis fits perfectly with the inferential thesis because it explains the derivation of the hypotheses that the perceptual system projects on the proximal stimulus. The result is a notion of the cognitive permeability of perception: seeing is an interpretive act which depends on the background knowledge of the subject. According to Fodor, however, it is possible to adhere to the inferential thesis without having to subscribe to the idea of cognitive permeability. From the fact that perceptual processes are inferential it does not follow that they must have access to the background knowledge of subjects. But, in order for all of this to work, perceptual systems must be "specialized" and "encapsulated." Our best theory of perception, therefore, seems to require a modular organization of the mind.
Gibson and the inferential thesis
So why is the inferential thesis necessary for Fodor and how does he justify it? In an article called How Direct is Visual Perception: Some Reflections on Gibson’s "Ecological Approach", Fodor and Zenon Pylyshyn criticize the conception of perception proposed by James Jerome Gibson in 1979. [10] The so-called ecological approach is in sharp contrast with the Establishment Theory maintained by cognitivists. The cognitivist thesis considers perception precisely to be a form of inference (seeing IS making hypotheses about the world). Three factors are necessary in order to sustain this thesis: memory, representation and a mechanism of elaboration able to transform—according to certain rules—some representations (premises) into other representations (conclusions). The reference to representations renders perception a mediated process which is highly indirect. Against this, Gibson proposes an hypothesis of perception capable, in his view, of doing without these three factors (and which is therefore qualified as “direct”) . To perceive, in his hypothesis, is to “directly gather”, without any representational intermediation, the invariant properties of the environment. But what are these properties?
Fodor points out that in order to avoid a "trivialization problem" (that is, the possibility that anything can be counted as an invariant property), Gibson must offer some criterion capable of tying together the gathering of information and the environmental invariants:
- “Suppose that under certain circumstances people can correctly perceive that certain things in their environment are of the type P. Since it is not possible to correctly perceive something of the type P unless it really is P, it is always trivially true that the things that can be perceived as P share an invariant property: their being P. Now, since, according to Gibson, that which people do when they perceive is to directly gather an appropriate invariant, for every perceptual result the following pseudo-explanation will always be valid: to perceive that something is P is to gather the invariant property P that the things of this type have. [11]
An illuminating example of the argumentative circularity which underlies the attempt to tie "direct grasping" to the invariant properties of objects can be seen in one of the key points of Gibson’s theory, according to Fodor. This is the thesis according to which the privileged invariants of objects are a sort of "affordances", or dispositional properties (being eaten, being grasped, being launched, etc.) which the objects offer to the organisms with which they come into ecological contact. Against this hypothesis, Fodor shows that such "affordances" presuppose direct perception and cannot be used to explain it.
The impossibility of direct perception of distal objects makes it necessary, according to Fodor, to adopt an inferential theory (necessarily mediated and indirect) of perception. The computational mechanism at the base of inferential processes is represented by the transducers. These are the mechanisms capable of providing a representation (in atomic structures of the LOT) of the dispositions of distal objects on the basis of the properties of the proximal stimulus. Given the huge gap which exists between proximal stimulus and distal object, it isn’t possible to propose a direct conception of perception (every perception is mediated by the representations which bridge the gap between distal object and proximal stimulus). Fodor’s conception remains within the context of the representational theory of the mind. Gibson, in his view, fails to clear the field of this theory because it is basically ineliminable, given that all of the semantic questions of perception seem to necessarily refer to it.
Fodor also addresses the problem of intentionality, one of the central aspects of the question of perceptual content which seems to be insoluble from the point of view of Gibson’s theory. The key point of Fodor’s criticism of the thesis of “direct perception” is that, given the same identical stimulus, we are able to form many different representations of the same object (seeing it as the morning star or as the evening star) and this in turn will tend to give rise to different behaviours. Even though there is a sense in which we see merely extensionally, therefore, seeing is substantially intentional. And the intentional aspects are, in fact, those which have causal relevance in any explanation of human behaviour. Inference, representation and intentionality seem to be, Fodor believes, intimately related. Gibson’s problems arise from not having comprehended this fact.
The limits of interpretation
If the question of intentionality is the critical notion in Fodor’s criticism of Gibson, in Observation Reconsidered the same notion plays a specular role: the limitation of the interpretationalist conception of perception.[12] The question regards the fixation of beliefs. Traditionally, the theories in this area tend to concentrate on two hypotheses: those which privilege the perceptual aspects and consider the fixation of beliefs to be dependent on perception and, therefore, on the relation with the external world; and those that, privileging instead the inferential relation between old and new beliefs, consider the fixation of beliefs to be substantially a process internal to the organism. While Fodor admits that the internal relation between beliefs has an enormous value, he maintains that this aspect has been overemphasized in recent philosophy of science and philosophy of mind. Fodor’s intent is to try to re-establish a just equilibrium between interpretation and observation.
The interpretationalist theories have a strong and consolidated tradition behind them. Ludwig Wittgenstein in his Philosophical Investigations (1953) distinguished between seeing that and seeing as using the well known experiment of ambiguous figures (the rabbit-duck of Jastrow). [13]Ambiguous figures force us to confront the fact that perception cannot be determined exclusively by sensory stimuli: given the same stimuli, it is possible to give two (or more) different interpretations of the same retinal configuration. Processes of interpretation are necessary in order to give sense to mere sensory stimulation. One author who has strongly insisted on this point is Jerome Bruner (1957), one of the founders of the New Look in the psychology of vision. [14] The most radical thesis in this regard, however, is that which, above all in linguistics and anthropology, has taken on the name of the Sapir-Whorf hypothesis . This hypothesis asserts that every perceptual act is determined and constituted by the entire web of beliefs of the individual (in fact, by his whole culture). This is a strongly holistic position which Fodor vehemently opposes and criticises. The tight relation between the interpretationalist hypothesis and holistic conceptions of belief is at the base of the idea of the dependence of perception on theory. This idea has profound repercussions also in epistemology. Thomas Kuhn (1962), Norwood Hanson (1958) and Nelson Goodman (1968), for example, maintain that the perception of the world depends on how the percipient conceives the world: two individuals (two scientists) who witness the same phenomenon and are steeped in two radically different theories will see two radically different things. It is our interpretation of the world, in this view, which determines that which we see.
Fodor attempts to establish that this theoretical paradigm is fallacious and misleading by demonstrating the impenetrability of perception to the background knowledge of subjects. The strongest case can be based on the evidence from experimental cognitive psychology itself: the persistence of perceptual illusions. Just knowing that the two horizontal lines in the Muller-Lyer illusion are equal does not prevent one from continuing to see them as one being longer than the other. It is this impenetrability of the information elaborated by the mental modules (informationally encapsulated) which limits the extent of interpretationalism.
The criticism of the interpretationalist hypothesis accounts for the common sense intuition (at the base of naïve physics) of the independence of reality from the conceptual categories of the epistemic subject. If the processes of elaboration of the mental modules are independent of the background theories, in fact, then it is possible to maintain the realist view that two scientists who embrace two radically diverse theories see the world exactly in the same manner even if they interpret it differently. The point is that is necessary to distinguish between observations and the perceptual fixation of beliefs. While it is beyond doubt that the second process involves the holistic relation between beliefs, the first is largely independent of the background beliefs of individuals.
Clearing the way for realism
Maintaining that scientists see the same world but interpret it differently does not explain, according to some critics, scientific dispute. According to Fodor, however, the true point in discussion is not the question of understanding what distinguishes various theories from each other, but what it is that permits scientific consensus. His answer to this problem is that scientific consensus is indissolubly linked to the thesis of the independence of observation from theories. Despite the interpretative differences, that which scientists share is that which depends on their belonging to a species endowed with certain common cognitive-perceptual structures. The question is also important because it has repercussions on the plane of semantics and mental content.
Guaranteeing that mental processes are (at least in part) independent from theories means opening the door to the possibility of a non-holistic (atomistic and casual) notion of mental content. Such a conception is necessary for Fodor in order to safeguard representational realism and, at the same time, attempt to solve the problems left open by methodological solipsism. The idea, in other words, is that the properties of the contents of mental states can depend, rather than exclusively on the internal relations of the system of which they are a part (the set of beliefs, for example), also on the causal relations with the world.
Intentional realism
In A Theory of Content and Other Essays, published by the MIT Press in 1990, Fodor takes up another of his most central notions with regard to the philosophy of mind: the question of representational realism.[15] Fodor needs to justify representational realism in order to justify the idea that the contents of mental states are expressed in symbolic structures of a propositional nature such as LOT. Such a justification is of enormous interest because it has immediate repercussions on some of the more general aspects of Fodor’s theory of the mental.
Fodor's criticism of Dennett
Fodor’s representational realism emerges out of his criticism of standard realism (which Fodor calls mere intentional realism). This latter view is characterized by two distinct assertions: one regarding the internal structure of mental states (according to which intentional attitudes are monadic in the sense described earlier) and another which concerns the fundamental conditions of a semantic theory (interpretable in terms of an isomorphism between causal roles and the inferential web). In the modern panorama of philosophy of mind, in which the functionalist view tends to prevail, the majority view seems to be that the first of these two assertions is false, but that the second is true. Fodor departs from functionalism in accepting the truth of the first thesis but rejecting (strongly) the truth of the second. Fodor’s argument in favour of representational realism starts from his criticism of the instrumentalism of Daniel Dennett. Dennett maintains that it is possible to be realist with regard to intentional states without having to commit oneself to the reality of mental representations. [16]But, according to Fodor, if one remains at this level of analysis, then there is no possibility of explaining why the intentional strategy works:
- "There is, nevertheless, a standard objection to instrumentalism...: it is difficult to explain why the psychology of beliefs/desires works so well, if the psychology of beliefs/desires is, in fact, false....As Putnam, Boyd and others have emphasized, from the predictive successes of a theory to the truth of that theory there is surely a presumed inference; and this is even more likely when (differently from the case of geocentric astronomy) we are dealing with the only theory in play which is predictively crowned with success. It is not obvious...why such a presumption should not militate in favour of a realist conception—against an instrumentalist one---of the interpretations of beliefs/desires." [17]
Productivity, compositionality and thought
But what are Fodor’s positive arguments in favour of the reality of mental representations in terms of the LOT? Fodor maintains that if language is the expression of thoughts and language is systematic, then thoughts must also be systematic. Systematicity in natural languages tends to be explained in term of two ulterior concepts: productivity and compositionality. The fact that systematicity and productivity depend on the compositional structure of language means that language has a combinatorial semantics. If thought also has a combinatorial semantics, then there must be a language of thought (i.e., thought must be in a kind of language).
These arguments serve to sustain the thesis of representational realism: not only intentional objects, but even the cognitive states in which such specific content occur are structured events. Representations must therefore exist. Moreover, they must have a specific format: they must be formulae of Mentalese, mental sentences whose syntax gives rise to the combinatorial semantics of the content which they vehicle.
The second argument that Fodor provides in favour of representational realism involves the processes of thought. This argument touches on the relation between the representational theory of mind (RTM, from now on) and models of its functional architecture. To assert that the sentences of Mentalese require peculiar processes of elaboration is to assert that they require a computational mechanism of a certain type. The syntactic conception of mental representations goes hand in hand with the computational theory of the mind: the idea that mental processes consist in calculations which act only on the form of the symbols which they elaborate. The computational theory of the mind (CTM) is based on a precise mechanical conception of thought based on Turing machines. Hence, the defence of a model of architecture which explicitly invokes classic artificial intelligence passes inevitably, according to Fodor, through a defence of the reality of mental representations.
Moreover, the formal-mechanical conception of thought processes has the advantage of highlighting the important parallelism between the causal role of symbols and the contents which they express. The theory which emerges goes hand in glove with the theory of the LOT, in fact, because it goes hand in glove with the syntactic theory of the mind (syntax is that which plays the role of mediation between the causal role of the symbols and the content which they vehicle). The advantage of a conception of this type is that the semantic relations between symbols can be "imitated" by their syntactic relations (the inferential relations which connect the contents of two symbols can be imitated by the syntax which regulates the derivation of one symbol from another).
Fodor's externalism
The fact that the LOT fits perfectly with the idea of a von Neumann type functional architecture of the mind is an important step forward toward the naturalization of the mental. Fodor acknowledges the cardinal role of functionalism in the direction of this process of naturalization, but he is also conscious of what he considers to be the intrinsic limits of that hypothesis. The principle defect consist in the fact that functionalism, if left unmodified, implies a conception of content (and meaning) which, focused exclusively on the causal relation between one symbol and another, remains totally internal to the symbolic system. The advantage of a conception of this type is that it makes it easier to formulate and explain a materialistic conception of the mental. The disadvantage is that it leaves out completely a non-secondary aspect of the project of naturalization of the mental: the justification of a theory of mental content (and of meaning) which takes account of the relation between representer and represented (which explains how it is possible that our representations can refer to the external world). Having abandoned his original position of methodological solipsism, Fodor more recently has maintained that functionalism, at least in its traditional form, can explain only some aspects of mental content and that is cannot be placed at the foundation of an entire semantic theory. He has become increasingly externalist in this regard.
The nature of content
From the beginning of the 1980’s, Fodor has adhered to a causal conception of mental content (and of meaning). This conception of content contrasts sharply with some of the basic assumptions of the inferential role semantics to which Fodor himself subscribed earlier in his career. The focal point of Fodor’s criticism of inferential (or conceptual) role semantics (IRS) is that while any true naturalization of the mental must inevitably include an explanation of content in atomistic terms, IRS has inevitably holistic implications.
Anti-holism
Fodor’s criticisms of holism are many and various. But he identifies the central problem with all the different notions of holism as the idea that the determining factor in semantic evaluation is the notion of an “epistemic bond” (P is an epistemic bond of Q if the semantic value of P is considered by an intentional system to be relevant for the semantic evaluation of Q). Meaning holism strictly depends on this notion. The identity of the content of a mental state (the identity of meaning), under holism, can only be determined by the totality of its epistemic bonds . And this makes the realism of mental states an impossibility:
- "If, as is certain, people differ in an absolutely general way in their estimations of epistemic relevance, and if we follow the holism of meaning and individuate intentional states by way of the totality of their epistemic bonds, the consequence will be that two people (or, for that matter, two temporal sections of the same person) will never be in the same intentional state. Therefore, two people can never be subsumed under the same intentional generalizations. And, therefore, intentional generalization can never be successful. And, therefore again, there is no hope for an intentional psychology." [18]
The asymmetric causal theory
Having criticized the idea that semantic evaluation concerns the internal relations between the units of a symbolic system, the way is open for Fodor to adopt an externalist position with respect to mental content and meaning. For Fodor, in recent years, the problem of naturalization of the mental is tied to the possibility of presenting “the sufficient conditions for which a piece of the world is relative to (expresses, represents, is true of) another piece” in non-intentional and non semantic terms. If this goal is to be attained within a representational theory of the mind, then the fundamental challenge for the causal theory is to establish the interpretation of the primitive non-logical symbols of the LOT. Fodor’s initial proposal is that what determines that the symbol for “water” in Mentalese expresses the property H20 is that the occurrences of that symbol are in certain causal relations with water. The intuitive (or naïve) version of this causal theory is what Fodor calls the “Crude Causal Theory.” According to this theory, the occurrences of symbols express the properties which are the causes of their occurrence. The term “horse”, for example, says of a horse that it is a horse. In order to do this, it is necessary and sufficient that certain properties of an occurrence of the symbol “horse” be in a nomological relation with certain properties which determine that something is an occurrence of horse.
The main problem with this theory is that of erroneous representations. There are two unavoidable problems with the idea that “a symbol expresses a property if it is nomologically necessary that all and only the presences of such a property cause the occurrences.” The first is that not ‘’all’’ horses cause occurrences of “horse”. The second is that not ‘’only’’ horses cause occurrences of “horse.” Sometimes the “A” (“horses”) are caused by A (horses), but at other times---when, for example, because of the distance or conditions of low visibility, one has confused a cow for a horse—the “A” (“horses”) are caused by B (cows). In this case the symbol “A” doesn’t express just the property A, but the disjunction of properties A or B. The crude causal theory is therefore incapable of distinguishing the case in which the content of a symbol is disjunctive from the case in which it isn’t. This gives rise to what Fodor calls the “problem of disjunction.”
Fodor responds to this problem with what he defines as a "a slightly less crude causal theory." According to this approach, it is necessary to break the symmetry at the base of the crude causal theory. Fodor must find some criterion for distinguishing the occurrences of “A” caused by As (true) from those caused by Bs (false). The point of departure, according to Fodor, is that while the false cases are ‘’ontologically dependent’’ on the true cases, the reverse is not true. There is an asymmetry of dependence , in other words, between the true contents (“A”= A) and the false ones (“A” = A or B). The first can subsist independently of the second, but the second can occur only because of the existence of the first:
- "From the point of view of semantics, errors must be accidents: if in the extension of "horse"
there are no cows, then it cannot be required for the meaning of "horse" that cows be called horses. On the other hand, if "horse" did not mean that which it means, and if it were an error for horses, it would never be possible for a cow to be called "horse." Putting the two things together, it can be seen that the possibility of falsely saying "this is a horse" presupposes the existence of a semantic basis for saying it truly, but not vice versa. If we put this in terms of the crude causal theory, the fact that cows cause one to say "horse" depends on the fact that horses cause one to say "horse"; but the fact that horses cause one to say "horse" does not depend on the fact that cows cause one to say "horse"..." (Fodor, 1987).
Functionalism
During the 1960's, various philosophers such as Donald Davidson, Hilary Putnam, and Fodor tried to resolve the puzzle of developing a way to preserve the explanatory efficacy of mental causation and so-called "folk psychology" while adhering to a materialist vision of the world which did not violate the "generality of physics." There proposal was, first of all, to reject the then dominant theories in philosophy of mind: behaviorism and the type identity theory. The problem with logical behaviorism was that it failed to account for causation between mental states and such causation seems to be essential to psychological explanation, especially if one considers that behavior is not an effect of a single mental event/cause but is rather the effect of a chain of mental events/causes. The type-identity theory, on the other hand, failed to explain the fact that radically different physical systems can find themselves in the same identical mental state. Besides being deeply anthropocentric (why should humans be the only thinking organisms in the universe?), the type-type theory also failed to deal with accumulating evidence in the neurosciences that every single human brain is different from all the others. Hence, the impossibility of referring to common mental states in different physical systems manifests itself not only between different species but also between organisms of the same species.
The solution to these problems, according to Fodor, is to be found in functionalism, a hypothesis which was designed to overcome the failings of both dualism and reductionism. Without going into detail here, the idea is that what is important is the function of a mental state regardless of the physical substrate which implements it. The foundation for this view lies in the principle of the multiple realizability of the mental. Under this view, for example, I and a computer can both instantiate ("realize") the same functional state though we are made of completely different material stuff (see graphic at right). On this basis functionalism can be classifed as a form of token materialism.
Criticism
Almost all of Fodor's major ideas have been challenged by a wide variety of philosophers of diverse orientation. For example, the language of thought hypothesis (or LOTH) has been accused of either falling prey to a regressus ad infinitum or of being superflous. Specifically, Simon Blackburn suggested in an article in 1984 that since Fodor explains the learning of natural languages as a process of formation and confirmation of hypotheses in the LOT, this leaves him open to the question of why the LOT itself should not be considered as just such a language which requires yet another and more fundamental representational substrate in which to form and confirm hypotheses so that the LOT itself can be learned. If natural language learning requires some representational substrate (the LOT) in order for it to be learned, why shouldn't the same be said for the LOT itself and then for the representational substrate of this representational subtrate and so on, ad infinitum? On the other hand, if such a representational substrate is not required for the LOT, then why should it be required for the learning of natural languages? In this case, the LOT would be superfluous.
Yet another argument againt the LOT was formulated by Daniel Dennet in 1981. The basic point of this argument is that it would seem, on the basis of the evidence of our behavior toward computers but also with regard to some of our own unconscious behavior, that explicit representation is not necessary for the explanation of propositional attitudes. During a game of chess with a computer program, we often attribute such attitudes to the computer, saying such things as "It thinks that the queen should be moved to the left". We attribute propositional attitudes to the computer and this helps us to explain and predict its behavior in various contexts. Yet no one would suggest that the computer is actually thinking or beleiving somewhere inside its circuits the equivalent of the propositional attitude "I believe I can kick this guy's butt" in Mentalese. The same is obviously true, suggests Dennett, of many of our everyday automatic behaviors such as "desiring to breath clear air" in a stuffy environment.
Fodor's self-proclaimed "extreme" concept nativism has been criticized by many linguists and philosophers of language. Kent Bach, for example, takes Fodor to task for his criticims of lexical semantics and polysemy. Fodor claims that there is no lexical structure to such verbs as "keep", "get", "make" and "put". He suggests that, alternatively, "keep" simply expresses the concept KEEP (Fodor capitalizes concepts to distinguish them from properties, names or other such entities). In Fodor's view then, "keep your clothes on", "keep your receipt" and "keep washing your hands" all share the same concept of KEEP. This concept presumably locks on to the unique external property of keeping. But, if this it true, then RETAIN must pick out a different property in RETAIN YOUR RECEIPT, since one can't retain one's cloths or retain washing one's hands. Fodor's theory also has a problem explaining how the concept FAST contributes, differently, to the contents of FAST CAR, FAST DRIVER, FAST TRACK, and FAST TIME.
But what makes Fodor's view of concepts extremely difficult to digest for many critics is simply his insistence that such a large, perhaps implausible, number of them are primitive and undefinable. For example, Fodor considers such concepts as BACHELOR, EFFECT, ISLAND, TRAPEZOID, VIXEN, and WEEK to be all primitive, innate and unanalyzable becasue they all fall into the category of what he calls "lexical concepts" (those for which our language has a single word). But, as Bach points out, the concept VIXEN almost certainly is composed out of the concepts FEMALE and FOX, BACHELOR out of SINGLE and MALE and so on.
References
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Books
- Hume Variations, Oxford University Press, 2003, ISBN 0199287333.
- The Compositionality Papers , (with E. Lepore), Oxford University Press 2002, ISBN 0199252165.
- The Mind Doesn't Work That Way: The Scope and Limits of Computational Psychology, MIT Press, 2000, ISBN 0262561468.
- In Critical Condition, MIT Press, 1998, ISBN 026256128X.
- Concepts: Where Cognitive Science Went Wrong, (The 1996 John Locke Lectures), Oxford University Press, 1998, ISBN 0198236360.
- The Elm and the Expert, Mentalese and its Semantics, (The 1993 Jean Nicod Lectures), MIT Press, 1994, ISBN 0262560933.
- Holism: A Consumer Update, (ed. with E. Lepore), Grazer Philosophische Studien, Vol 46. Rodopi, Amsterdam, 1993, ISBN 9051837135.
- Holism: A Shopper's Guide, (with E. Lepore), Blackwell, 1992, ISBN 0631181938.
- A Theory of Content and Other Essays, MIT Press, 1990, ISBN 0262560690.
- Psychosemantics: The Problem of Meaning in the Philosophy of Mind, MIT Press, 1987, ISBN 0262560526.
- The Modularity of Mind: An Essay on Faculty Psychology, MIT Press, 1983, ISBN 0262560259.
- Representations: Essays on the Foundations of Cognitive Science, Harvard Press (UK) and MIT Press (US), 1979, ISBN 0262560275.
- The Language of Thought, Harvard University Press, 1975, ISBN 0674510305.
- The Psychology of Language, with T. Bever and M. Garrett, McGraw Hill, 1974, ISBN 0394306635.
- Psychological Explanation, Random House, 1968, ISBN 0070214123.
- The Structure of Language, with Jerrold Katz (eds.), Prentice Hall, 1964, ISBN 0138547033.