Philosophical Foundations of Neuroscience. P. M. S. Hacker

Philosophical Foundations of Neuroscience - P. M. S. Hacker


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But it is evident that this is not all that Marr meant. He claimed that numeral systems (roman or arabic numerals, binary notation) are representations. However, such notations have nothing to do with causal correlations, but with representational conventions. He claimed that ‘a representation for shape would be a formal scheme for describing some aspects of shape, together with rules that specify how the scheme is applied to any particular shape’,28 that a formal scheme is ‘a set of symbols with rules for putting them together’,29 and that ‘a representation, therefore, is not a foreign idea at all – we all use representations all the time. However, the notion that one can capture some aspect of reality by making a description of it using a symbol and that to do so can be useful seems to me to be a powerful and fascinating idea.’30 But the sense in which we ‘use representations all the time’, in which representations are rule-governed symbols, and in which they are used for describing things, is the semantic sense of ‘representation’ – not a new homonymical causal sense. Marr has fallen into a trap of his own making.31 He in effect conflates Ullman’s representations*, which are causal correlates, with linguistic representations, which are symbols or symbol systems with a syntax and meaning determined by conventions.

      Reply to Ullman: Young on ‘maps’ and Frisby on ‘symbolic representations’

      Reply to the second objection (Gregory) that, in ascribing psychological attributes to the brain, neuroscientists are not committing the mereological fallacy, but merely extending the psychological vocabulary analogically

      It is not semantic inertia that motivates our claim that neuroscientists are involved in various forms of conceptual incoherence. It is, rather, the acknowledgement of the requirements of the logic of psychological expressions. Psychological predicates are predicable only of an animal as a whole, not of its parts. No conventions have been laid down to determine what is to be meant by the ascription of such predicates to a part of an animal, in particular to its brain. So the application of such predicates to the brain or the hemispheres of the brain transgresses the bounds of sense. The resultant assertions are not false, for to say that something is false we must have some idea of what it would be for it to be true – in this case, we should have to know what it would be for the brain to think, reason, see and hear, etc., and to have found out that as a matter of fact the brain does not do so. But we have no such idea, and these assertions are not false. Rather, the sentences in question lack sense. This does not mean that they are silly or stupid. It means that no sense has been assigned to such forms of words, and that, accordingly, they say nothing at all, even though it looks as if they do.

      Reply to Blakemore’s objection that applying psychological predicates tothe brain is merely metaphorical

      To be sure, the term ‘representation’ here signifies merely systematic causal connectedness. That is innocuous enough. But it must not be confused with the sense in which a linguistic item (e.g. a presentation) can be said to represent something fairly or unfairly, a map to represent that of which it is a map, or a painting to represent that of which it is a painting. Nevertheless, such ambiguity in the use of ‘representation’ is perilous, since it is likely to lead to a confusion of the distinct senses. Just how confusing it can be is evident in Blakemore’ s further observations:


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