ABSTRACT
Logic, it is often said, is the study of valid arguments. It is a systematic attempt to distinguish valid arguments from invalid arguments. At this stage that characterization suffers from the fault of explaining the obscure in terms of the equally obscure. For what after all is validity? Or, for that matter, what is an argument? Beginning with the latter easier notion we can say that an argument has one or more premises and a conclusion. In advancing an argument one purports that the premise or premises support the conclusion. This relation of support is usually signalled by the use of such terms as ‘therefore’, ‘thus’, ‘consequently’, ‘so, you see’. Consider that old and boring example of an argument: Socrates is a man. All men are mortal. Therefore, Socrates is mortal.
