In the history of Western logic, Symbolic logic is a relatively recent development. What set symbolic logic apart from traditional logic is its leanings towards mathematics and symbolization. A general theory of deduction aims to explain the relations between premises and conclusion in deductive arguments and to provide techniques for discriminating between valid and invalid deduction. Two great bodies of logical theory have sought to achieve these ends. The first, called “classical” (or Aristotelian) logic. The second, called “modern logic or symbolic logic.” Symbolic logic of today owes its origin primarily to Frege and Russell, and then to Peano and many others. If they had helped the gensis of symbolic logic, other 20^{th} CE mathematicians and philosophers such as Brouwer, Godel, Cantor, Hilbert, Wittgenstein, Tarski, Zermelo, Gentzen must be acknowledged for joing in their efforts and for their worth contributions towards its steady growth. Here we will only study **Propositional Logic** means **Truth-functional Logic**.** **

Unit-XV: Truth-functional Logic

Unit-XVI: Truth-functional Compound Statements

Unit-XVII: Validity and Invalidity by Truth-table Method

Unit-XVIII: Statement Forms