maio 31, 2013

Intuition Pumps quotes by Daniel Dennett

Giving an intentional-stance* interpretation of some sub-personal brain structure is like putting a comment on a few lines of code; when done well, it provides an illuminating label, not a translation into English or other natural language of some formula in Brainish that the brain is using in its information-processing.

(*) the level of abstraction in which we view the behavior of a thing in terms of mental properties [wikipedia]

In general, the cryptographer’s maxim holds: if you can find one solution to a puzzle, you’ve found the only solution to the puzzle. Only special circumstances permit as many as two solutions, but such cases show us that the existence of only one single solution to a question like this is not a metaphysical necessity, but just the immensely probable result of very powerful constraints.

People are much more complicated than either crossword puzzles or computers. They have convoluted brains full of neuromodulators, and these brains are attached to bodies that are deeply entwined with the world, and they have both an evolutionary and a personal history that has embedded them in the world with much more interpenetration than the embedding of a crossword puzzle in a linguistic community. So Ruth Millikan (for instance) is right that given the nature of design constraints, it is unlikely in the extreme that there could be different ways of skinning the cat that left two radically different, globally indeterminate, tied-for-first-place interpretations. Indeterminacy of radical translation* is truly negligible in practice. Still, the principle survives. The reason we don’t have indeterminacy of radical translation is not because, as a matter of metaphysical fact, there are “real meanings” in there, in the head (what Quine called the “museum myth” of meaning, his chief target). The reason we don’t have indeterminacy in the actual world is that with so many independent constraints to satisfy, the cryptographer’s maxim assures us that it is a vanishingly small worry. When indeterminacy threatens in the real world, it is always just more “behavioral” or “dispositional” facts—more of the same—that save the day for a determinate reading, not some mysterious “causal power” or “intrinsic semanticity.” Intentional interpretation almost always arrives in the limit at a single interpretation, but in the imaginable catastrophic case in which dual interpretations survived all tests, there would be no deeper facts to settle which was “right.” Facts do settle interpretations, but it is always “shallow” facts that do the job.

(*)  Radical translation is a term by W. V. O. Quine to describe the situation in which a linguist is attempting to translate a completely unknown language, which is unrelated to his own, and is therefore forced to rely solely on the observed behavior of its speakers in relation to their environment. [wikipedia]

How can meaning make a difference? It doesn't seem to be the kind of physical property, like temperature or mass or chemical composition, that could cause anything to happen. What brains are for is extracting meaning from the flux of energy impinging on their sense organs, in order to improve the prospects of the bodies that house them and provide their energy. The job of a brain is to “produce future” in the form of anticipations about the things in the world that matter to guide the body in appropriate ways. Brains are energetically very expensive organs, and if they can’t do this important job well, they aren’t earning their keep. Brains, in other words, are supposed to be semantic engines. What brains are made of is kazillions of molecular pieces that interact according to the strict laws of chemistry and physics, responding to shapes and forces; brains, in other words, are in fact only syntactic engines. [..] Don’t make the mistake of imagining that brains, being alive, or made of proteins instead of silicon and metal, can detect meanings directly, thanks to the wonder tissue in them. Physics will always trump meaning. A genuine semantic engine, responding directly to meanings, is like a perpetual motion machine—physically impossible. So how can brains accomplish their appointed task? By being syntactic engines that track or mimic the competence of the impossible semantic engine.

Natural selection is an automatic reason-finder; it “discovers” and “endorses” and “focuses” reasons over many generations. The scare quotes are to remind us that natural selection doesn't have a mind, doesn't itself have reasons, but it is nevertheless competent to perform this “task” of design refinement. This is itself an instance of competence without comprehension. Let’s just be sure we know how to cash out the scare quotes. Consider a population with lots of variation in it. Some members of the population do well (at multiplying); most do not. In each case we can ask why. Why did this one have surviving offspring while these others did not? In many cases, most cases, there is no reason at all; it’s just dumb luck, good or bad. But if there is a subset, perhaps a very small one, of cases in which there is an answer, a difference that happens to make a difference, then what those cases have in common provides the germ of a reason. This permits functionality to accumulate by a process that blindly tracks reasons, creating things that have purposes but don’t need to know them. The Need to Know principle reigns in the biosphere, and natural selection itself doesn't need to know what it’s doing. So there were reasons before there were reason-representers. The reasons tracked by evolution I have called “free-floating rationales," [...] There are reasons why trees spread their branches, but they are not in any strong sense the trees’ reasons. Sponges do things for reasons; bacteria do things for reasons; even viruses do things for reasons. But they don’t have the reasons; they don’t need to have the reasons. There are reasons aplenty for these behaviors, but in general, organisms need not understand them. They are endowed with behaviors that are well designed by evolution, and they are the beneficiaries of these designs without needing to know about it. This feature is everywhere to be seen in nature, but it tends to be masked by our tendency, adopting the intentional stance, to interpret behavior as more mindful and rational than it really is.

Then what might the self be? I propose that it is the same kind of thing as a center of gravity, an abstraction that is, in spite of its abstractness, tightly coupled to the physical world. [...] It may be a “theorist's fiction,” but it is a very valuable fiction from which a lot of true predictions can be generated. [...] What then is a center of narrative gravity? It is also a theorist’s fiction, posited in order to unify and make sense of an otherwise bafflingly complex collection of actions, utterances, fidgets, complaints, promises, and so forth, that make up a person. It is the organizer of the personal level of explanation. Your hand didn't sign the contract; you did. [...] In the same way that we can simplify all the gravitational attractions between all the parts of the world and an obelisk standing on the ground by boiling it down to two points, the center of the earth and the center of gravity of the obelisk, we can simplify all the interactions—the handshakes, the spoken words, the ink scrawls, and much more—between two selves, the seller and the buyer, who have just completed a transaction. Each self is a person, with a biography, a “backstory,” and many ongoing projects. Unlike centers of gravity, selves don't just have trajectories through space and time; they gather as they go, accumulating memories and devising plans and expectations.

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