I came across Marvin Minsky’s 2006 book _The Emotion Machine_ (draft available at his site). I briefly looked at what he had to say about commensense, the biggest hurdle for AI. Here is how he estimates how much a typical person knows, ‘a few dozen millions of items of knowledge’:
Everyone knows a good deal about many objects, topics, words, and ideas—and one might suppose that a typical person knows an enormous amount. However, the following argument seems to suggest that the total extent of a person’s commonsense knowledge might not be so vast. Of course, it is hard to measure this, but we can start by observing that every person knows thousands of words, and that each of those must be linked in our minds to as many as a thousand other such items. Also a typical person knows hundreds of uses and properties of thousands of different common objects. Similarly, in the social realm, one may know thousands of things about tens of people, hundreds of things about hundreds of people, and tens of useful items about as many as a thousand people.
This suggests that in each important realm, one might know perhaps a million things. But while it is easy to think of a dozen such realms, it is hard to think of a hundred of them. This suggests that a machine that does humanlike reasoning might only need a few dozen millions of items of knowledge.
I found it worthwhile to read a bit in this work by one of the big defenders of ‘knowledge-intensive AI’; the old-fashioned kind that I am a child of. (I only recently learnt that the pun GOFAI for good old-fashioned AI should probably be pronounced with ‘o’ as in ‘goof’.) I saw that (in the same chapter on commonsense) Minsky briefly comments on the currently fashionable ideas that we need to copy the brain and that we need to harvest the web.
Here are some points in a review by the neurologist Richard Restak that make me curious:
Actually, the loss of cells results from passive disuse — use it or lose it — rather than active deletion.
Of the 1.1 trillion cells in the human brain, only 100 billion are neurons.
[A]natomical interaction of neurons highlights only one aspect of brain functioning. Equally important are alterations of the brain’s chemical messengers, the neurotransmitters, along with changes in local and distributed electrical fields.
I looked at Minsky’s web site after I Wolfram|Alpha’ed him together with Norbert Wiener, about whom Lambert spoke to me yesterday. (Beware: Wolfram|Alpha is the latest geek tool; innovative, useful, addictive.)