Proof
| Proposition | Derivation |
|---|---|
| Given | |
| Given | |
| Material implication | |
| Modus ponens |
| Proposition | Derivation |
|---|---|
| Given | |
| Given | |
| Material implication | |
| Transposition | |
| Modus ponens |
Read more about this topic: Disjunctive Syllogism
Famous quotes containing the word proof:
“If some books are deemed most baneful and their sale forbid, how, then, with deadlier facts, not dreams of doting men? Those whom books will hurt will not be proof against events. Events, not books, should be forbid.”
—Herman Melville (18191891)
“Ah! I have penetrated to those meadows on the morning of many a first spring day, jumping from hummock to hummock, from willow root to willow root, when the wild river valley and the woods were bathed in so pure and bright a light as would have waked the dead, if they had been slumbering in their graves, as some suppose. There needs no stronger proof of immortality. All things must live in such a light. O Death, where was thy sting? O Grave, where was thy victory, then?”
—Henry David Thoreau (18171862)
“He who has never failed somewhere, that man can not be great. Failure is the true test of greatness. And if it be said, that continual success is a proof that a man wisely knows his powers,it is only to be added, that, in that case, he knows them to be small.”
—Herman Melville (18191891)