Jaina Logic

Author(s): T G Kalghatgi
Publisher: Raja Krisen Jain Charitable Trust New Delhi

Page 96

In his Introduction to Logic Copi maintains that truth and falsehood may be predicated of propositions, but never of arguments. And the properties of validity and invalidity can belong only to deductive arguments, never to propositions, There is a conjection between the validity or invalidity of the argument and the truth or falsehood of its premises and conclusion. But the connection is by no means a simple one, Some valid arguments contain only the propositions. For exampleAll whales are mammals; All mammals have lungs. .. All whales have lungs. But an argumeot may contain false propositions exclusively and be valid nevertheless, for example All spiders have 6 legs; All six legged creatures have wings. • All spiders have wings. A deductive argument fails to establish the truth of its conclusion if it is unsound. And to test the truth or falsehood of the premises is the task of science in general. The logician is not so much interested in the truth or falsehood of propositions as in the logical relations between them. The use of language is necessary, and the use of language complicates our problem. Certain accidental or misleading propositions may make the task of investigating the logical relations between the propositions more difficult."
Bertrand Russell and Moore had profound influence in shaping the course of analytical philosophy. Both rejected Idealism. Russell rejected internality of relations propounded by Idealists. The idealist error is, in the main, a logical error. They failed to see that all meaningful propositions are of subject-predicate form. Wittgenstein's task was primarily the activity of classifying language. The philosophers' task is to show the person who is puzzled by metaphysical questions that it is meaningless and unanswerable. The famous last sentence of the Tractatus- "Where-of one cannot speak, there-of one must be silent" expresses the essential doctrine of Wittgenstein's early view. Later philosophers of analysis, like John Austin,
152. Copi Introduction to Logic: (McMillan 1972. 4th Edn.) pp. 32-35