Single Idea 11148

[catalogued under 5. Theory of Logic / B. Logical Consequence / 3. Deductive Consequence |-]

Full Idea

A deduction is a discourse in which, certain things having been supposed, something different from the things supposed results of necessity because these things are so.

Gist of Idea

Deduction is when we suppose one thing, and another necessarily follows


Aristotle (Prior Analytics [c.328 BCE], 24b18)

Book Reference

Aristotle: 'Prior Analytics', ed/tr. Smith,Robin [Hackett 1989], p.2

A Reaction

Notice that it is modal ('suppose', rather than 'know'), that necessity is involved, which is presumably metaphysical necessity, and that there are assumptions about what would be true, and not just what follows from what.