The symbolic approach to Artificial intelligence in based on the idea that a symbolic system (read Turing machine) has the neccessary and sufficient means to display intelligent action. This 'sentence' is known as the physical symbol system hypothesis. Nothing wrong with it. All it says is that a computer can be intelligent, if we'd only know how to make it so. I would think that this is the bare minimum amount of optimism one could display before diving headlong into a field. Though I think this hypothesis subsumes most of the connectionist work, the symbolic approach is associated with more top down methods.
Of course, I cannot discuss symbolic Ai without discussing LISP. LISP is the most beautiful programming language I’ve ever encountered. Programming in it is as much an art as a science. Given below are my implementations of some popular themes. So that the less scrupulous may not use these programs as assignments etc, I’m not providing any documentation (thus cleverly implying that I had the documentation, I didn’t put it in).
Resolution for prepositional calculus