Deductive reasoning Deductive reasoning Deductive reasoning, also deductive logic, logical deduction is the process of reasoning from one or more statements (premises) to reach a logically certain conclusion. Deductive reasoning goes in the same direction as that of the conditionals, and links premises with conclusions. If all premises are true, the terms are clear, and the rules of deductive logic are followed, then the conclusion reached is necessarily true. Deductive reasoning (""top-down logic"") contrasts with inductive reasoning (""bottom-up logic"") in the following way; in deductive reasoning, a conclusion is reached reductively by applying general rules which hold over the entirety of a
Analytic philosophy sought to understand language (and hence philosophical problems) by using formal logic to formalize the way in which philosophical statements are made. Wittgenstein developed a comprehensive system of logical atomism in his "Tractatus Logico-Philosophicus" (, 1921). He thereby argued that the universe is the totality of actual states of affairs and that these states of affairs can be expressed by the language of first-order predicate logic. Thus a "picture" of the universe can be construed by means of expressing atomic facts in the form of atomic propositions, and linking them using logical operators. During the late 1920s, to 1940s, a