The idea of representing classes and their relation expressed in a proposition by use of circles was originally developed by Euler, a Swiss mathematician of eighteenth century. But its subsequent development and refinements are due to Venn, a British logician belonging to nineteenth century.
Logic is concerned with arguments. It distinguishes good arguments from the bad ones. An argument consists of propositions Out of which one is called the conclusion and others are called premises. Arguments are either deductive or inductive
This is a kind of mixed syllogism in which the major premise is a disjunctive proposition, whereas the minor premise and the conclusion are categorical propositions. A disjunctive proposition consists of two component propositions, which are called its disjuncts.
This is a kind of mixed syllogism in which the major premise is a hypothetical proposition, the minor premise is a categorical proposition and the conclusion is a categorical proposition. Symbolically it is represented as,
This is a kind of mixed syllogism in which the major premise is an alternative proposition and the minor premise is a categorical proposition affirming one of the alternatives of the major premise. The conclusion is a categorical proposition that denies the other alternative.