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.

Through all the years of experimenting and research, I never once made a discovery. I start where the last man left off. ... All my work was deductive, and the results I achieved were those of invention pure and simple.
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.
susan stebbingIf a lack of empirical foundations is a defect of the theory of logical probability, it is also a defect of deductive logic.
david stoveIt 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.
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.
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.
randal marlin