Years ago Ned Block defined a system known today as a Blockhead ("Troubles with Functionalism", Minnesota Studies in the Philosophy of Science) to illustrate a problem that look-up tables pose for the Turing test. Blockhead is a "stupid" machine that stores all possible conversations within some limited duration and, thus, passes the Turing Test. This is, of course physically impossible, as Frank Tipler argues with back of the envelope calculations in The Physics of Immortality:
… the human brain can code as much as 10^15 bits is correct, then since an average book codes about 10^6 bits, it would require more than 100 million books to code the human brain. It would take at least thirty five-story main university libraries to hold this many books. We know from experience that we can access any memory in our brain in about 100 seconds, so a hand simulation of a Turing Test-passing program would require a human being to be able to take off the shelf, glance through, and return to the shelf all of these 100 million books in 100 seconds. If each book weighs about a pound (0.5 kilograms), and on the average the book moves one yard (one meter) in the process of taking it off the shelf and returning it, then in 100 seconds the energy consumed in just moving the books is 3 x 1019 joules; the rate of energy consumption is 3 x 1011 megawatts. Since a human uses energy at a normal rate of 100 watts, the power required is the bodily power of 3 x 1015 human beings, about a million times the current population of the entire earth. A typical large nuclear power plant has a power output of 1,000 megawatts, so a hand simulation of the human program requires a power output equal to that of 300 million large nuclear power plants. As I said, a man can no more hand-simulate a Turing Test-passing program than he can jump to the Moon. In fact, it is far more difficult.In typical philosophical fashion we suspend the laws of physics and look to conceivability and logical possibility to analyze this scenario. Given that Blockheads are logically possible, what does it say about the Turing Test? Should we not attribute intelligence to Blockhead merely because he uses brute-force methods? It is difficult to know how to respond to this. When we are trying to break a candidate program for the Turing test we ask it questions that, while coherent, have high surprisal. This is used to defeat look-up tables/canned responses, which are the hallmarks of poorly designed AI. However, in this case it is stipulated that the table has all of the possible answers, so such a strategy is useless. So, we have a system that passes the Turing Test with abhorrent methods. Is this really a problem?
Let's consider the larger set of agents I call Brutes. Brutes use any or all algorithms that are foreign to ours, or are, in general, unappealing in their processes. This can be in the form of look-up tables, randomized answers, Liebnizian monsters that have monadic processes that never talk to one-another or receive any input, etc. However, Brutes, by fiat pass the Turing test. Now suppose after a neuro-imaging breakthrough we discover some percentage of the population utilizes some abhorrent algorithms in their thinking. Are we to then discount them as being mere Brutes, not truly thinking, feeling people? To do so would be ridiculous. Now suppose that some percentage of the population use nothing but abhorrent algorithms. Can we dismiss them? Again, I do not think so. To maintain otherwise seems to me to be a result of arbitrary algorithmic chauvinism or finding consciousness and intelligence to be an essence that exists apart from function—the same intuition that allows philosophers to take zombie arguments seriously and succumb to the quagmire of privileged access.
In a way, talk of Brutes and Blockheads just misses the point of the Turing test, which is to dissociate the methods, substrate and appearance of the candidate system from the difference that makes a difference: behavior.
I do not see how we can hold an agent's (or potential agent’s) algorithms against them.
Posted by John at January 28, 2004 08:55 PMOf course Frank Jackson thought I was nuts for arguing this way, though he was quite good-natured about it.
Posted by: John at January 28, 2004 08:58 PMYou are a very Wicked Behaviourist
Posted by: ~o at January 29, 2004 01:37 AMWhen a user launches an attack against a server using a program which guesses at passwords using all possible variations of words, then letters and numbers to try and guess a password, this is what is called a Brute Force Attack. I guess you advocate doing the same thing to try and pass the Turing Test? I'm not sure exactly what you advocate here. are you sugesting that any attempts are valid when striving for an outcome? or are you saying that humans may actually use vastly differing methods when thinking, and that they should all be considerered human, even if they are merely mindlessly computing algorithms that make them efficient Starbucks Barista Drones.
I'm sort of new to reading the work of Certified Computational Philosophers such as yourself. But I'd like to invite you to educate me on such topics. (maybe in your comments section)
How the Mind Works - Steven Pinker
Consciousness Explained - Daniel Dennett
The Mind's I - Dennett and Hofstader
All three are in the bookshelf closest to the hall. I had more good intros but now you have to get them from Katie.
You should check this stuff out elex, I think you would find some things very appealing about it. It is participating in an extended discussion about how minds are and are not like computers.
Posted by: ~o at January 30, 2004 02:01 AMI might agree with Mr. Jackson. How something thinks is important as what it does.
If you encountered someone who was saying true things but arriving at them through unsound methods, then you would think differently of them. It would change your estimation of future behavior. So, I think that past behavior is not enough to justify consideration of 'rationality' on its own.
Posted by: ~o at January 30, 2004 02:06 AMElex,
That is the right sense of ‘brute force’: any method that churns through a combinatorial space (with the hope that processing power will be sufficient) to find the answer, rather than exploiting regularities and compressing information. I do not advocate this approach to passing the Turing test. In real life, even relatively simple problems are intractable when you approach them this way.
Keep tuning in and you are bound to get caught up in arguments. This is a good way to learn. See: CP Books and CP Papers
Otis,
>>How something thinks is important as what it does.
You are entirely right, when we are not talking about a thought experiment that tells us how it is going to act (namely, passing the Turing test). Passing the Turing test presumes acting reliably (at least as much as we humans do). In this case, my point stands. The dilemma we are supposed to deal with is the conceptual adequacy of the Turing test verses the logical possibility of using abhorrent methods to pass the test. Which trumps what?
However, when we do Turing tests in the real world, we do try to indirectly test how the answer came to be, because poor methods make for poor intelligence. I strongly suspect that the methods used by my imagined Brutes are not possible in this universe, but this is irrelevant to the thought experiment—we are just addressing conceptual necessities. No doubt, by this point, you are reminded why you did not major in philosophy.
Also, I imagine you are referring to more than just deductively sound methods for reasoning in contrast to “unsound methods”. It is doubtful that we make use of such deductive methods very often, though logicians emulate them.
A few questions:
Do you judge my actions (generally) rational without knowledge of how I do it? Are you justified in doing so?
Are you equating ‘rationality’ with ‘intelligence’ or ‘consciousness’?
>
How something thinks is important? Since when? The Turing test is a proposed determiner for *when* something thinks. How it accomplishes that thinking is neither here nor there.
Submarines may seem awfully unsound, swim-wise, to fish, but they can swim through the seven seas nonetheless. (Aside: Who started this analogy? Haugeland?)
Posted by: Nihilo at January 30, 2004 04:16 PMI have heard shots over the bow, but no return volley...you see, one of the combatants was caught on a bridge.
Posted by: John at January 31, 2004 12:31 PMyes.
Sorry about that. I've lost the plot a bit.