Adaptation and representation — an introduction

Anne Reboul and Adrianna Wozniak, Institute for Cognitive Sciences, CNRS

1. Introduction

The notion of representation plays an important — if not a central — role in philosophy, biology, ethology, linguistics and neurosciences. It is also the criterion for differentiating cognitive from behaviorist approaches. (Innate) representations and their relation with adaptive processes will be the topic of the present paper.

We will begin by a tentative definition, according to which a representation is the way by which an object is given to the subject. It should be clear that this definition is absolutely neutral regarding the origin of the representation, i.e. whether it is innate or acquired. What will interest us here is the criterion for the truth of a representation (in the case in which it is propositional) or its adequation to reality (when it is not). In the case of acquired representations, those that are produced by experience, such a criterion seems, at least intuitively, relatively transparent: a representation is semantically adequate in as much as it agrees with its object. Additionally, the very fact that it is caused by its object acts as a guarantee of its semantic adequacy (the guarantee in question is not a guarantee of truth (for propositional representations), but the guarantee that the representation has a cause in the present experience of the subject and the guarantee that there is a criterion of semantic adequacy). The problem is, however, rather more complex when the representation does not arise as the result of an experience, but is genetically determined, in other words, when it is innate. In such a case, prima facie, no experience guarantees the adequacy of the representation to its object. This is what we will call the problem of the missing criterion. The present paper aims to show that it is indeed a problem and that some attempts to solve it may not be as successful as is generally thought.

The problem, however, will only arise in case there actually are innate representations. Can there be a proof of the existence of innate representations? Briefly, we want to follow Quine’s (1960, 5) path here, when he says “Substracting his [environmental] cues from his world view, we get man’s net contribution as the difference. This difference marks the extent of man’s conceptual sovereignty — the domain within which he can revise theory while saving data” and suggest the following formula:

innate (for a species) = representation — (environmental contribution + individual variability)

In other words, to know what is innate in a (possibly species specific) representation (or in a representation schema), one must substract from the representation the contribution of the environment and what is variable from one member of the species considered to the next. It has been claimed by both psychologists and philosophers that the human species shares a common conceptuel schema, which up to a point determines the human view of the world. This has been claimed not only for relatively mundane things such as natural kinds (trees, animals, etc.), but also for domains such as religion (see Boyer 2001). Though some variation has indeed been found, notably in the domain of color and in that of space, as attested by linguistic variation in the expression of color categories and spatial relations (see Roberson et al. 2005, Levinson 2003, Kay & Regier 2006), it is not clear that it amounts to anything much in terms of criticizing the notion of a innate human conceptual schema. Indeed, Gopnik (2001) has claimed that such variations are not only limited in scope, but are either notational variants or are equivalent in terms of cognitive efficiency. Let us suppose, for the time being, that there is such a thing as a human conceptual schema which, in one way or another, actually constrains the human ability for knowledge (The term “constrain” is not intended positively — as unleashing unlimited intellectual powers — or negatively — as implying basic limits on epistemic abilities —, but as neutral). If this is so, how can such a representation schema be consider as fitting external reality? What, if anything, is the criterion which could determine such a fit? In 1942, Konrad Lorenz tackled the problem in a way which was designed not so much to solve it as to dissolve it: he proposed that in fact exactly the same criterion and the same guarantee should be applied for innate as for acquired representations. In other words, in both cases, what guaranteed the fitness of the representation was that it was caused by an (external) object. The difference between acquired and innate representations, on this view, is not the presence and absence of a relevant experience, but rather the time scale of that experience: whereas acquired representations are caused by an experience during the life of an individual (during its ontogeny), innate representations are caused by (repeated) experiences during the lives of ancestors (during the phylogeny of the species). Thus, the guarantee and adequacy of innate representations is to be determined by the same criterion as the guarantee and adequacy of acquired representations, i.e. the causal relation between the representation and its object. Up to a point this makes Lorenz’s view a kind of ancestor to the current philosophical position on representation which is called semantic externalism.

2. Semantic externalism

Semantic externalism has its roots in a paper by Putnam (1975) which relied on a by now famous thought experiment. Putnam supposed that there exists a planet, microphysically identical with the Earth — Twin Earth — but for one detail: what passes for water on Twin Earth is not H2O, but XYZ. On this planet, live counterparts of Earthians, who, being microphysically identical with Earthians, are also behavorially indistinguishable from them. When Earthian Ruth says, on Earth, “Water is liquid at room temperature”, Twin Earthian TWRuth says the same. The question which interested Putnam was whether they actually mean the same thing or two different things. If they mean the same thing, then given the (type) identity of their brain, meaning is in the head. If they don’t — and for the same reason — meaning is not in the head. As is well-known, Putnam answered his question in the negative: though they utter the same sentence and have type-identical brains, Ruth and TWRuth don’t mean the same thing, as the word “water” in Ruth’s utterance refers to H2O, while, in TWRuth’s utterance, it refers to XYZ. Thus, in Putnam’s immortal phrase, “meanings ain’t in the head”. This has more often than not been taken as implying that error is impossible: the meaning of whatever you say is determined by external reality (hence the name “semantic externalism”) and it is thus impossible that it should not agree with it3 (see the papers in Nucettelli 2003).

Semantic externalism has developed since Putnam, through, notably, Ruth Millikan’s (1993, 2000, 2004, 2005) and Dretske’s (1981) work. Basically, Dretske and Millikan have pursued Putnam’s externalism and have used it to try and naturalize intentionality, that is the fact that mental states are about, aimed at, objects. Their way of doing it, very roughly, is through a view which is, in some ways at least, very near to Lorenz’s. They see representations as either phylogenetic or ontogenetic, i.e. as caused by the (external) environment, as adaptations to it (in as much as they can influence behavior) either at the level of the species (during the course of its evolution) or at the level of the individual (for instance through associative learning). In other words, for them, representations are biological features of the organism, on a par with its organs. For instance, according to Millikan (1993), a representation has a proper function, determined by its origin (either phylogenetic or ontogenetic), just as an organ has: and, just as an organ (e.g. the heart) will still have a proper function (e.g. pumping blood) even if it malfunctions, a representation will still have its proper function (representing the (type of) object which caused it), even if misapplied. In other words, this version of semantic externalism, which has been prominent in the current endeavor to naturalize the mind, is heavily dependent on central features of the theory of natural selection.

3. Phylogenetic externalism

Thus, according to semantic externalism in its naturalistic version, the guarantee and criterion for semantic adequacy should be the same for innate and for acquired representations. As far as innate representations are concerned, it rests on a strong separation between the organism or the species in which the representations occur and their environments. This agrees with one major tenet of the theory of natural selection, i.e. phylogenetic externalism, which supposes that what evolves — e.g. the representations and the organisms of which they are features — is always the same thing and what causally triggers the evolution — the external environment — is also always the same thing. In other words, the causality involved is not only asymmetrical (which is as it should be), it is also one-sided: environmental factors cause change (evolution) in the organisms, but never the reverse. More precisely, given genetic variability among individuals, the role of the environment is that of a sieve: it will let some organisms live and reproduce, while others will not, changing the species. In brief, the organism provides the genetic variability, but the environment is the judge of the fitness of the specific variant provided. In other words, the adaptive evolution is always a function of the environment. However, natural selection being only operative on hereditary features, it only concerns heritable characteristics. Evolutive causality is only relevant for inheritable (hereditary) properties.

In what follows we will only concentrate on innate representations, which are the only representations of which it can be said that they are inheritable. In its naturalistic version, semantic externalism, in keeping with Lorenz’s position, sees innate representations as adaptations in the sense of the theory of evolution. Thus, the missing criterion which they propose is the causal evolution of such representations during the phylogeny of the species: this is supposed to act as a guarantee of the semantic adequacy of the (innate) representation to its object. This seems very close to considering that, for innate representations, semantic adequacy is equivalent to biological fitness, i.e. that it is gradual and it depends on the environment. So the main question regarding this solution to the missing criterion problem is whether being an adaptation, i.e. being caused by past (phylogenetic) experience, can be considered as a guarantee, on a par with the present experience of the object as a cause of the representation for acquired representations, of semantic adequacy.

4. Two kinds of causality…

Most current works in the Modern Synthesis (The Modern Synthesis was born of the fusion of modern genetics with the Darwinian logic behind the theory of natural selection) relie on population genetics, i.e. a statistical approach to evolutionary dynamics (gene frequency). This relies on an abstract kind of causality, called either property causality (Sober 1987) or causal general assertions (Glennan 2002). More commonly, the notion of cause is relative to specific instances. This second kind of causality, called token causality (Sober 1987) or causal singular assertions (Glennan 2002), is distinct from the first in as much as, rather than relying on statistic tendencies, it concerns actual, individual, causal events. This can be seen as the difference between the two following assertions:

1. Smoking causes lung cancer.
2. My cousin died of lung cancer because he was a heavy smoker.

In 1, the causality is statistic: in other words, though some non-smokers do die of lung cancer, the probability of getting lung cancer is higher for smokers than for non-smokers (property causality) and 1 still is true. In 2, the causality is specific: if my cousin was a non-smoker, he could still have died from lung cancer, but 2 would be false.

We would like to say that the guarantee and criterion of semantic adequacy, though it is causal in both cases, does not rely on the same kind of causality for innate and for acquired representations:

• for innate representations, the guarantee and criterion of semantic adequacy rest on property causality;
• for acquired representations, the guarantee and criterion of semantic adequacy rest on token causality.

This raises a question: given that the criterion and guarantee of semantic adequacy rest on different kind of causality depending on whether they apply to innate or acquired representations, can it be claimed that they are indeed one and the same for these two kinds of representations? And, if they are not, what is the consequence for innate representations and their adequation with reality?

5. Two kinds of criteria?

The present question, we want to emphasize, is not on whether there are innate representations, or whether they originated as adaptations. It is whether the fact that they originated as adaptations can function as a guarantee and criterion of their semantic adequacy. As seen above, the Externalist view of innate representations suggests that there is a proximity, if not indeed equivalence, between the guarantee and criterion of semantic adequacy for such representations and their fitness value (their contribution to the fitness of the organism, as mesured in terms of number of viable offspring). We will leave the question of whether the fitness value of innate representations can be seen as a criterion of semantic adequacy for later, concentrating right now on the (externalist) guarantee and criterion proposed by Lorenz and contemporary externalist semanticists.

A good way of approaching the question is to look at how the guarantee and the criterion of semantic adequacy operate for acquired representations. In acquired representations, the actual experience of an object causes (in the sense of token causality) its representation. It is because a specific object is perceived or experienced at a given time by a given individual that the representation caused in that individual by that object can be considered as guaranteed and as semantically adequate (Up to a point, it is because in hallucination the representation occurs without this causal relation to reality that hallucinations do not have any guarantee of semantic adequacy. It is not clear that hallucinations have criteria of semantic adequacy for precisely the same reason). Could the same thing be said about innate representations? The answer is obviously in the negative. In the case of an innate representation, by definition, no present (ontogenetic) experience is necessary for the existence of the representation. Accordingly, no present (ontogenetic) experience can act as either a guarantee or a criterion of semantic existence for the representation. It seems thus that the different kinds of causality implied by the innate and acquired representations means that there is not one kind of guarantee and criterion, but two kinds of guarantees and criteria. In other words, the validity of the guarantee and criterion of semantic adequacy for acquired representations cannot be extrapolated to the guarantee and criterion of semantic adequacy for innate representations. Hence, the guarantee and criterion for innate representations may be valid, but their validity cannot be established on the same grounds as for acquired representations because property causality does not work in the same way as token causality. We will now turn to the validity of the guarantee and criterion for innate representations.

6. Can past experiences guarantee the semantic adequacy of innate representations?

As we have just seen, present experiences guarantee the semantic adequacy of acquired and present representations, because of the token causality between these experiences and these representations. The difference between the case of acquired and innate representations is that in the first present experiences guarantee the semantic adequacy of present representations, while in the second past experiences are supposed to guarantee the semantic adequacy of present representations. The problem is whether they can really do so.

This is tantamount to the following question: can property causality act as a guarantee between past experiences and present (innate) representations? As seen above, property causality is statistics, which is why smoking can cause lung cancer, eventhough some non-smokers die of lung cancer. However, though it is certainly true that smoking can cause lung cancer, this does not make it true that a non-smoker who dies from lung cancer died because he was a smoker. In the same way, the fact that in the past a given (type) of object (token-)caused a given representation in a given organism and even the fact that that type of object ended up (property-)causing that type of representation to become an adaptation, cannot guarantee that a present specific representation of that type is semantically adequate. In other words, the fact that in the past a type of representation added to the fitness value of the members of a species and hence became an adaptation (an innate representation) cannot, in any way, be a guarantee that it is semantically adequate today.

This raises one further question: does it still have a positive fitness value today if it is no longer semantically adequate?

7. Conclusion

Millikan’s view is that the proper function of an organ or of a representation is wholly determined by what it was selected for in the past (i.e. what it was an adaptation to). For a representation, its proper function is what it was selected to represent in the past, in other words, there is an equivalence between what a representation means (its meaning or signification) and what the proper function of that representation is. If this is the case, then the meaning of a present (innate) representation is independent of what produces it now. It only depends on what used to cause it. If this is so, then innate representations, supposing that their original (property-)cause has disappeared, because for instance the environment has changed, provided that they are produced by another element in the present environment, still represent that original cause. In other words, they can be systematically false.

This consequence has been anticipated in Sperber’s (1994) org story. According to Sperber, orgs developped an (innate) representation of elephants who used to come in their environment and trampled them. That feature disappeared though the (innate) representation subsisted, being now triggered by another (and new) feature of the environment, i.e. trains passing nearby. Sperber, in keeping with Millikan’s notion of proper cause, distinguishes between the proper domain of the representation and its actual domain. In other words, the distinction allows us to say that the orgs’ innate representation is (property-) caused by the original factor — which determines its proper domain —, but is (token-) caused by the new factor — which determines its actual domain. Thus, the proper domain does not coincide (now) with the actual domain. As shown by this example, past experience cannot guarantee the semantic adequacy of present innate representations.

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