symbolic inference

The derivation of new facts from known facts and inferencerules. This is one of the fundamental operations of

artificial intelligence and logic programming languages

like Prolog.

Inference is a basic part of human reasoning. For example

given that all men are mortal and that Socrates is a man, it

is a trivial step to infer that Socrates is mortal. We might

express these symbolically:

man(X) =@# mortal(X).

man(socrates).

("if X is a man then X is mortal" and "Socrates is a man").

Here, "man", "mortal" and "socrates" are just arbitrary

symbols which the computer manipulates without reference to or

knowledge of their external meaning. A forward chaining

system (a production system) could use these to infer the

new fact

mortal(socrates).

simply by matching the left-hand-side of the implication

against the fact and substituting socrates for the variable X.

(1994-10-28)