 now dear learners, this is all about the unit 1, nature of formal logic now i think you have understood and all about the main summary of this unit that is nature of formal logic are in a very nutshell, that is the term logic is derived from the Greek word logos which means thought or reasoning thus logic is a study of reasoning and Aristotelian logic is a formal logic formal logic is concerned exclusively with the principles of deductive reasoning and it is concerned with the forms rather than with the content of propositions deductive logic is formal logic as opposed to inductive logic which is non formal logic or material logic logicians are primarily concerned with the correctness or incorrectness of arguments the distinction between correct and incorrect argument is the central problem with which logic deals Aristotelian study of syllogism focused on arguments containing propositions of a spatial kind called categorical propositions categorical propositions consist of subject, predicate and a copula modern logic or symbolic logic is a formal logic or symbolic logic is a developed form of Aristotelian logic the difference between symbolic logic and Aristotelian logic is not a difference of kind but a difference of degree dear learners in propositional calculus the letters of the alphabets like the small letters p q r s t and so on stand for propositions and these letters are used in propositional calculus are known as propositional variables because they can stand independently for any proposition thus in symbolic logic compound propositions are symbolized by means of variables and constants now dear learners you know that the symbolic form p dot q p value q p implies q or negation p etcetera are called truth functions because the truth or falsity of these functions depend on the truth and falsity of the constituent variables like p and q symbolic logic as formal logic is concerned with the validity or invalidity of different argument forms rather than with the validity or invalidity of particular individual arguments formal logic is not concerned with the empirical truth or falsity of propositions it is concerned with formal truth and formal validity so dear learners these are all the very basic points of the unit 1 nature of formal logic now dear learners to know the units to understand the unit in a very comprehensive manner you have to study some books that books are for you you can write down the names of the books then you can take some Kishor Singh's book that is modern logic that is volume 1 and you can take Arvind Amcopy that is symbolic logic fifth edition and you can take also one book that is Krishna Jain the books name is a text book of logic and also you can take another book very important book that is Arvind Amcopy Mohen and Karl Kohen and Priyadol Srinigetli and Monika Prabhakar's book that is introduction to logic dear learners I think you have understood the unit and you go through the unit and you study all the books which I have referred to you thank you