Thursday 2/28

Thursday 2/28

Robot Intentionality VI: Theories of Meaning

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Today we took up a problem that has been lurking for some time: Our focus since encountering the skeptical challenge posed by the Chinese Room Thought Experiment has been to understand how original intentionality is possible. Recall that one way of describing it is as the symbol-grounding problem. How is it, that is to ask, that the symbols subject to rule-government manipulations vis-a-vis Turing Machines mean anything? For that is what the Chinese Room Thought Experiment seems to show. The squiggles and squoggles that are the objects of Searle-in-the-Chinese-Room's obsessive transcriptions mean nothing to Searle apart from their association via the rule-book he so assiduously follows. The lurking problem is this: Quite apart from squiggles and squoggles, how do the words in natural language come to have the meanings they do in the first place? Put another way, how is linguistic communication possible?

On what I am calling the Naive View, the token of a piece of linguistic communication (scribbles on paper, modulated sound-waves, or what have you) expresses an idea or thought--quite literally a psychological state in the speaker--and arouses, if you will, the same idea or thought in the listener's mind. Thus an expression may be about a state of affairs in the world, but the connection between expression and world is not direct: Mental states mediate.

To be sure, we have no idea (pun intended) whether the listener's mediating idea is the same as the speaker's. If what the expression is about depends on the idea it expresses, then we seem to be in a very real quandary. I've no more access to your ideas than you do to mine, since psychological states are private. The public continuity linguistic communication presupposes fails because ideas are not publicly accessible, nor are (for example, and put very crudely) pressure variations in the air caused by my flapping my meat and causing the flapping of your meat plausible candidates to secure my communication (expressing? squirting?) of my idea that the cat is in the cat-tree so you have the idea of the cat's being in the cat-tree.

Enter Frege. In order to solve the Frege Puzzle, he insisted that reference be mediated. Yet he recognized that using psychological states--peculiar as they presumably are to the individual--won't secure linguistic communication. As an alternative, he posited what we now call the descriptivist theory of meaning. According to descriptivism, names pick out their senses which in turn pick out a reference, where senses are understood (loosely) as sets of definite descriptions--hence, descriptivism. Moreover, Frege was a realist about senses. They exist and are publicly accessible in such a way that we can secure communication by their use. The speaker's use of a term expresses its sense, which sense is then used by the listener to pick out the term's reference in turn. We can extend descriptivism to entire sentences by supposing that compositionality is as true of sentences as any complex expression with respect to both sense and reference. Thus the sense of a complex expression (sentence) is a function of the senses of its parts, the senses of its parts determine their references, while the reference of the whole complex expression (sentence) is likewise a function of its (entire) sense, or thought where complete sentences are concerned, as Frege deceptively calls it.

I say "deceptively" because Frege's use of such apparently psychological terms as 'concept' and 'thought' are nothing of the sort. As Frege understands them, concepts and thoughts are not ideas in the head but logical abstractions which are nonetheless real and, crucially, at the heart of the possibility of linguistic communication. For suppose, as we discussed, that the thought expressed by a statement genuinely were an idea in the mind of the speaker: Since minds are impenetrably closed to any but the speaker himself, no one else could have access to the thought expressed, from which it follows that no one would be able to understand (grasp the meaning) of what anyone said. So whatever concepts and thoughts are, they must be publicly accessible if they are going to do the hard work of underwriting (making possible, that is) linguistic communication. They can't, then, be ideas or psychological items if they are to do this work because of the essentially inaccessible nature of mental states.

For example, in uttering "the cat is in the cat-tree", I grasp a thought (the sense of the expression), which is the very same sense you must grasp if I am to successfully communicate to you that the cat is in the cat-tree. My idea of the cat's being in the cat tree (perhaps a mental picture of it) won't do, since you have no way of accessing my mental picture. So the thought expressed by "the cat is in the cat-tree" is graspable only if it is public, not private, yet all mental states are wholly private. If the thought is publicly graspable as it must be if communication is at all possible--that is, if sense determines reference--then it cannot be an idea in my head or a mental picture of any sort.

It follows on the Fregean Descriptive Theory of Reference that you grasp what I mean by my utterances when you grasp the very same sense of them I grasp in making them, and it is from their sense that their reference, or how they connect with the world, is determined. This presupposes that senses be non-psychological, real (albeit abstract) items in the world which can be apprehended or grasped by the language users regardless of their attitudes towards, or psychological states about, these senses.

To be sure, senses are metaphysically peculiar, which suggests that we dispense with mediated reference altogether by rejecting them. The relationship between a term and what it means, in this case, is direct inasmuch as there are no intervening ideas or senses. This is sometimes called the theory of direct reference or the causal/historical theory of reference, since the way in which terms come to designate is specified by their causal history in the linguistic community insofar as (in clear cases) it can be traced back to baptismal or christening 'tagging' event whereby the Titannic, say, is christened "Titanic", or Aristotle is baptised, anachronistically enough, "Aristotle".

Next time we take up a fascinating and powerful argument for direct reference and consider its implications for two further issues bearing on intentionality: Externalism and Extended Minds.