harnad@mind.UUCP (Stevan Harnad) (10/26/86)
In Message-ID: <8610190504.AA08059@ucbvax.Berkeley.EDU> on mod.ai CUGINI, JOHN <cugini@nbs-vms.ARPA> replies to my claim that >> there is no rational reason for being more sceptical about robots' >> minds (if we can't tell their performance apart from that of people) >> than about (other) peoples' minds. with the following: > One (rationally) believes other people are conscious BOTH because > of their performance and because their internal stuff is a lot like > one's own. This is a very important point and a subtle one, so I want to make sure that my position is explicit and clear: I am not denying that there exist some objective data that correlate with having a mind (consciousness) over and above performance data. In particular, there's (1) the way we look and (2) the fact that we have brains. What I am denying is that this is relevant to our intuitions about who has a mind and why. I claim that our intuitive sense of who has a mind is COMPLETELY based on performance, and our reason can do no better. These other correlates are only inessential afterthoughts, and it's irrational to take them as criteria. My supporting argument is very simple: We have absolutely no intuitive FUNCTIONAL ideas about how our brains work. (If we did, we'd have long since spun an implementable brain theory from our introspective armchairs.) Consequently, our belief that brains are evidence of minds and that the absence of a brain is evidence of the absence of a mind is based on a superficial black-box correlation. It is no more rational than being biased by any other aspect of appearance, such as the color of the skin, the shape of the eyes or even the presence or absence of a tail. To put it in the starkest terms possible: We wouldn't know what device was and was not relevantly brain-like if it was staring us in the face -- EXCEPT IF IT HAD OUR PERFORMANCE CAPACITIES (i.e., it could pass the Total Turing Test). That's the only thing our intuitions have to go on, and our reason has nothing more to offer either. To take one last pass at setting the relevant intuitions: We know what it's like to DO (and be able to do) certain things. Similar performance capacity is our basis for inferring that what it's like for me is what it's like for you (or it). We do not know anything about HOW we do any of those things, or about what would count as the right way and the wrong way (functionally speaking). Inferring that another entity has a mind is an intuitive judgment based on performance. It's called the (total) turing test. Inferring HOW other entities accomplish their performance is ordinary scientific inference. We're in no rational position to prejudge this profound and substantive issue on the basis of the appearance of a lump of grey jelly to our untutored but superstitious minds. > [W]e DO have some idea about the functional basis for mind, namely > that it depends on the brain (at least more than on the pancreas, say). > This is not to contend that there might not be other bases, but for > now ALL the minds we know of are brain-based, and it's just not > dazzlingly clear whether this is an incidental fact or somewhat > more deeply entrenched. The question isn't whether the fact is incidental, but what its relevant functional basis is. In other words, what is it about he brain that's relevant and what incidental? We need the causal basis for the correlation, and that calls for a hefty piece of creative scientific inference (probably in theoretical bio-engineering). The pancreas is no problem, because it can't generate the brain's performance capacities. But it is simply begging the question to say that brain-likeness is an EXTRA relevant source of information in turing-testing robots, when we have no idea what's relevantly brain-like. People were sure (as sure as they'll ever be) that other people had minds long before they ever discovered they had brains. I myself believed the brain was just a figure of speech for the first dozen or so years of my life. Perhaps there are people who don't learn or believe the news throughout their entire lifetimes. Do you think these people KNOW any less than we do about what does or doesn't have a mind? Besides, how many people do you think could really pick out a brain from a pancreas anyway? And even those who can have absolutely no idea what it is about the brain that makes it conscious; and whether a cow's brain or a horse-shoe crab's has it; or whether any other device, artificial or natural, has it or lacks it, or why. In the end everyone must revert to the fact that a brain is as a brain does. > Why is consciousness a red herring just because it adds a level > of uncertainty? Perhaps I should have said indeterminacy. If my arguments for performance-indiscernibility (the turing test) as our only objective basis for inferring mind are correct, then there is a level of underdetermination here that is in no way comparable to that of, say, the unobservable theoretical entities of physics (say, quarks, or, to be more trendy, perhaps strings). Ordinary underdetermination goes like this: How do I know that your theory's right about the existence and presence of strings? Because WITH them the theory succeeds in accounting for all the objective data (let's pretend), and without them it does not. Strings are not "forced" by the data, and other rival theories may be possible that work without them. But until these rivals are put forward, normal science says strings are "real" (modulo ordinary underdetermination). Now try to run that through for consciousness: How do I know that your theory's right about the existence and presence of consciousness (i.e., that your model has a mind)? "Because its performance is turing-indistinguishable from that of creatures that have minds." Is your theory dualistic? Does it give consciousness an independent, nonphysical, causal role? "Goodness, no!" Well then, wouldn't it fit the objective data just as well (indeed, turing-indistinguishably) without consciousness? "Well..." That's indeterminacy, or radical underdetermination, or what have you. And that's why consciousness is a methodological red herring. > Even though any correlations will ultimately be grounded on one side > by introspection reports, it does not follow that we will never know, > with reasonable assurance, which aspects of the brain are necessary for > consciousness and which are incidental...Now at some level of difficulty > and abstraction, you can always engineer anything with anything... But > the "multi-realizability" argument has force only if its obvious > (which it ain't) that the structure of the brain at a fairly high > level (eg neuron networks, rather than molecules), high enough to be > duplicated by electronics, is what's important for consciousness. We'll certainly learn more about the correlation between brain function and consciousness, and even about the causal (functional) basis of the correlation. But the correlation will really be between function and performance capacity, and the rest will remain the intuitive inference or leap of faith it always was. And since ascertaining what is relevant about brain function and what is incidental cannot depend simply on its BEING brain function, but must instead depend, as usual, on the performance criterion, we're back where we started. (What do you think is the basis for our confidence in introspective reports? And what are you going to say about robots'introspective reports...?) I don't know what you mean, by the way, about always being able to "engineer anything with anything at some level of abstraction." Can anyone engineer something to pass the robotic version of the Total Turing Test right now? And what's that "level of abstraction" stuff? Robots have to do their thing in the real world. And if my groundedness arguments are valid, that ain't all done with symbols (plus add-on peripheral modules). Stevan Harnad princeton!mind!harnad harnad%mind@princeton.csnet (609)-921-7771