Theory of Mind
Another ingredient of human thought is the ability to understand, or infer, what is in the minds of other people. This is again recursive, since I might not only infer what another individual is thinking, but also infer that she infers what I am thinking. As I suggest in chapter 8, mind reading is not the product of extrasensory perception or psychic emanations, but is rather a mental process, dependent on common situations, shared experience, and an understanding that other minds are like our own. Mind reading is critical to human cooperation, but may also underlie some of our more deceitful practices, such as lying, stealing, and cheating. Believe me.
As I explain in chapter 9, language depends critically on theory of mind. Indeed it is itself one of the mechanisms by which we read the minds of others. Unlike animals calls, which consist of relatively fixed signals, language is intrinsically ambiguous, and meaning must be inferred not only from what a person says (or signs), but also from what one knows about that person and what one shares with her. A conversation is more a shared stream of thought than the transmission of information, and can often be carried on with a minimal use of words.
This part of the book continues the theme that language is not so much an independent biological faculty as part of a more general cognitive capacity—in this case the capacity to share our thoughts and emotions. The social nature of language is one reason that no one has yet succeeded in having meaningful conversations with a computer. Perhaps we might make an exception of ELIZA, the famous computer program that simulated Rogerian psychotherapy, which essentially operated by using stock phrases triggered by key words in the patient’s utterances. Well, maybe some conversations are a bit like that, but I like to think that even psychotherapy may have evolved into something a little more meaningful.