A system is said to be coherent if every fact in the system is related every other fact in the system by relations that are not merely conjunctive. A **deductive** system affords a good example of a coherent system.

— As quoted in

If a lack of empirical foundations is a defect of the theory of logical probability, it is also a defect of **deductive** logic.

— The Rationality of Induction, Oxford: Clarendon, 1986. Page 176, last paragraph.

The Greeks... discovered mathematics and the art of **deductive** reasoning. Geometry, in particular, is a Greek invention, without which modern science would have been impossible.

— Bertrand Russell (1945)

It was, for all I know, the first **deductive** theory of the world , the first **deductive** cosmology : One further step led to theoretical physics, and to the atomic theory.

— Karl Popper, in

A system is said to be coherent if every fact in the system is related every other fact in the system by relations that are not merely conjunctive. A **deductive** system affords a good example of a coherent system.

— Lizzie Susan Stebbing (1930)

Aristotle writes that persuasion is based on three things: the ethos, or personal character of the speaker; the pathos, or getting the audience into the right kind of emotional receptivity; and the logos, or the argument itself, carried out by abbreviated syllogisms, or something like **deductive** syllogisms, and by the use of example.

— Chapter Two, History Of Propaganda, p. 47