According to the Turing Test, if you have an extended email conversation probing to see whether your interlocutor is a person or a machine and you eventually decide it is a person, but it turns out to be a computer, then we ought to say that the computer is intelligent. Taken as a test for consciousness (probably not Turing's own intention), there are two important considerations in favour. One is that the test provides a neat way of avoiding any prejudice against computers on the grounds that they don't look human. The other is the thought that at the end of the day our best evidence that other people are conscious may be their intelligent linguistic behavior. There are also two important considerations against the test. One is that there seems no reason to say that the computer couldn't fool us without being conscious. The other is the thought that my confidence that other humans on conscious might depend on my knowledge that I myself am conscious and that you and I have a similar...

The nub of Searle's provocative argument is the claim that if you are given only symbols, without being told their meaning, plus rules for manipulating those symbols to generate an output of symbols, where those rules never talk about meaning, then you are never going to learn the meaning of those symbols, however intelligent the output seems to those who do know their meaning. Computers (at least traditional ones) seem like that: they are symbol manipulating machines who never work with meanings, only 'shapes' (or patterns of electrical impulse). The argument has considerable force, but it raises an obvious question: what could we have that computers don't that enables us to wring meaning out of the mere sound waves and electromagnetic radiation that our senses detect?

Jackson argues that even if you had complete physical knowledge of some conscious state -- such as the sensation of a color or a sound -- that you had never experienced --say because you were color blind, or deaf --you would still learn something new about that sensation if you went on to enjoy it yourself. Since you already knew all the physical facts about that experience and you learned new facts about it when you had the experience, there must be non-physical facts about it for you to have learned. You make a legitimate response to this argument by questioning the assumption that you would learn something new if you had complete physical knowledge. Who knows? But I confess that I don't find this reply entirely satisfying. Although complete physical knowledge is a very different from our actual situation, I am moved by the fact that as I learn more purely physical facts about sensations these seem to tell me nothing about what experiencing that sensation is like, what it feels like,...

If a stick starts out being two feet long and then it becomes twice as short, it becomes one foot long. Since there is such a thing as absolute zero, I would have thought that twice as cold as temperature T Kelvin is T/2. (But I'm assuming that the Kelvin scale is linear...) So work out what the zero you have in mind corresponds to in degrees Kelvin and, as they say in England, Bob's your uncle.

One attraction of this analogy stems from the distinction between hardware and software (program) for computers. Computers are physical things, but the same program may run on physically different computers, so the states of the program are not to be identified with particular physical states. Instead, it seems that program states are to be understood 'functionally', in terms of their causes and effects, which may in turn be other program states. What makes the analogy attractive is the thought that mental states might also be functional states. Thus the same kind of thought might be 'run' on or 'realized' in different physical states on different occasions, just as the same program might be run on different types of computer hardware. One attraction of this idea is that it seems to capture the intuition that mental states are not simply identifiable with lumps of matter, while avoiding any suggestion that they are spooky non-physical stuff.

As I read Hume, he is saying that children form beliefs about the unexamined, and they do this because of their 'natural instinct' of supposing that the future will be like the past. And Hume thinks that adults are just the same. We might think that we have good reasons for our beliefs about the unexamined, but what Hume's brilliant skeptical argument seems to show is that there can be no such reasons. The deal is that this is, for many of us, a deeply disturbing conclusion.

'Because' is often used as the connective of explanation, and a great many of the explanations we give are causal. But not all: explanations in pure mathematics and at least most philosophical explantions are not causal, but are still given with a 'because'. So the appearance of 'because' in your example does not in itself show that desires are causes of actions (though I think they are). By the way, here is a non-causal explanation I particularly like. Suppose a bunch of sticks are thrown in the air, so they spin and tumble as they fall. Now take a snapshot of the sticks before any of them hit the ground. More of the sticks are near the horizontal than near the vertical. Why? The answer is because there are more ways for a stick to be near the horizontal than near the vertical. This is a geometrical not a physical fact, so it is not a cause, but it provides a lovely explanation. (To see that it is a fact, think of a single stick with a fixed midpoint. How many ways can it be vertical? (Tw0.)...

Whenever we talk about representations (and philosophers can't stop talking about them), it is important to distinguish between the representations and the things they represent. Representations, such as sentences and thoughts, are human products, but what they represent need not be. You can't think without thinking; it doesn't follow that you can only think about thinking. Still, one might worry that it would be an incredible coincidence if human categories lined up with the categories of the world as it is in itself. But work in the philosophy of language in the last few decades as suggested a way this might not be a coincidence, by showing how the shape of our own categories may in fact be determined by the world's categories. If you would like to follow this idea up, read Saul Kripke's wonderful Naming and Necessity . (And then if you would like to start worrying all over again how the mind could shape categories, read his equally wonderful but more disturbing Wittgenstein on Rules...

This is a matter of dispute. First of all, there is dispute over whether religion has any innate component, for example whether there is an innate predisposition towards religion. Second, if there is an innate component, there is a further dispute over whether this is present because it is in itself advantageous from a natural selection point of view, or whether instead it is a by-product of other cognitive traits having nothing particular to do with religion that have such an advantage.

The answer to this may be yes and no. Yes, colors are or are caused by micro-properties of the surface of objects, but apparently quite different micro-structures may correspond to the same perceived color.