formal logic

The science of correct reasoning, based upon the premise that the validity of an argument is a function of its structure or logical form. The modern embodiment of formal logic is symbolic logic. This is the study of valid inference in artificial, precisely formulated languages, the grammatical structure of whose sentences or well-formed formulas is intended to mirror, or be a regimentation of, the logical forms of their natural language counterparts. These formal languages can thus be viewed as models of fragments of natural language. Like models generally, these models are idealizations, typically leaving out of account such phenomena as vagueness, ambiguity, and tense. But the idea underlying symbolic logic is that to the extent that they reflect certain structural features of formal arguments, the study of valid inference in formal languages can yield insight into the workings of those arguments.

"visual dictionary"