Philosophy of mind is an interesting part of the subject and is capable of study within the sub-branch of philosophy called Science. One of the interesting areas of discussion is the nature of intelligence and how we can define it and recognize it. This potentially has important implications for subdivisions of science, such as computation, other branches of philosophy, such as Religion, Ethics and Mathematics. There has been much discussion of this subject, either directly or by implication on at least two other threads (Free Will and Are You Religious) and I thought it has sufficient merit of its own to treat it in its own right and to expand its boundaries beyond the religious. Let's start off with a little starter for 10 ... HB didn't give a reference for his quote, but it appears to be copied from this OU site, which may be based, in part, upon the section starting at the bottom of page 66 of Darwin's The Formation of Vegetable Mould, Through the Action of Worms with Observations on Their Habits. It is reasonable, from the context of the original thread and the highlighting of two key words, to infer that HB was using this to support a hypothesis of earthworm intelligence. A few interesting (to me) statements pop out of Darwin's book: p93: If we consider these several cases, we can hardly escape from the conclusion that worms show some degree of intelligence in their manner of plugging up their burrows. p97: Mr. Romanes, who has specially studied the minds of animals, believes that we can safely infer intelligence, only when we see an individual profiting by its own experience. If worms have the power of acquiring some notion, however rude, of the shape of an object and of their burrows, as seems to be the case, they deserve to be called intelligent; for they then act in nearly the same manner as would a man under similar circumstances. However, my quick skimming of the Darwin's work leads to another possibility, namely worm's brains have some capability to adapt to different leaves but not due to explicit 'reasoning'. Some forms of artificial neural network exhibits this kind of behaviour and yet we would not (all things being equal) regard a 'simple' classifier as 'intelligent'. Nor would we regard it 'having some notion', instead more likely thinking of it as adaptive function. Intelligence is something that we appear to consider in terms of using explicit reasoning to deduce and infer. So that we might regard a 'human' as intelligent because they notice some properties of leaves that correlate with their suitability for hole plugging and develop a suitable theory, but we would not necessarily concede that an 'automatic leaf traction machine' had any such powers of reasoning, even if it had a 'learning' mechanism that allowed 'experience' to adapt its internal parameters to deal with new leaf types or limited environmental conditions. A computer can play chess, handle calculus or classify underwater sounds - but does it have any ''idea' of what it's doing? I suspect one of the key aspects lies in the concept of 'meaning', possibly what Darwin refers to as 'a notion'. Thoughts? --------------------------------------------------- Just for the record, and using an intuitive sense of what intelligence is, I don't think the earthworm is intelligent, but I do think a dog is intelligent.