Quotes About Logic

Arthur Conan Doyle

You will not apply my precept, he said, shaking his head. How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth? We know that he did not come through the door, the window, or the chimney. We also know that he could not have been concealed in the room, as there is no concealment possible. When, then, did he come? Sherlock Holmes in The Sign of the Four

It was easier to know it than to explain why I know it. If you were asked to prove that two and two made four, you might find some difficulty, and yet you are quite sure of the fact.

It is a capital mistake to theorise before you have all the evidence. It biases the judgement.

When the impossible has been eliminated, all that remains no matter how improbable is possible.

Whatever remains, However improbable

Una vieja máxima mía dice que, cuando has eliminado lo imposible, lo que queda, por muy improbable que parezca, tiene que ser la verdad.

Ya le he explicado otras veces que en esta clase de casos lo extraordinario constituye antes que un estorbo, una fuente de indicios. La clave reside en razonar a la inversa, cosa, sea dicho de paso, tan útil como sencilla, y poquísimo practicada

I have no data yet. It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. But the note itself. What do you deduce from it?

actor, even as science lost an acute reasoner, when he became a specialist in crime.

The question now was, who was the man, and who was it brought him the coronet? "It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth.

Este o greÈ™eal? capital? s? emiÈ›i teorii înainte de a avea informaÈ›ii. F?r? s?-È›i dai seama, începi s? distorsionezi faptele ca s? se potriveasc? cu teoriile, în loc ca teoriile s? se potriveasc? cu faptele.

I have already thought it over,' said Rubashov. 'I reject your proposition. Logically, you may be right. But I have had enough of this kind of logic. I am tired and I don't want to play this game anymore. Be kind enough to have me taken back to my cell.

A faith is not acquired by reasoning. One does not fall in love with a woman, or enter the womb of a church, as a result of logical persuasion. Reason may defend an act of faith-but only after the act has been committed, and the man com­mitted to the act.

Dialectic is the art of intellectual fencing; and it is only when we so regard it that we can erect it into a branch of knowledge.

It is easy to understand that in the dreary middle ages the Aristotelian logic would be very acceptable to the controversial spirit of the schoolmen, which, in the absence of all real knowledge, spent its energy upon mere formulas and words, and that it would be eagerly adopted even in its mutilated Arabian form, and presently established as the centre of all knowledge.

Aristotle's example is as follows: A Moor is black; but in regard to his teeth he is white; therefore, he is black and not black at the same moment.

To talk of rational beings apart from man is as if we attempted to talk of heavy beings apart from bodies.

Nothing is without a reason why it is rather than it is not

Abstract reasoning serves rather to fix the immediate cognition of the understanding for reason by setting it down in abstract concepts, that is, by making it clear,e i.e. putting it into a state to be interpreted for others, to make it meaningful.f –

Reason is of a feminine nature: it can give only after it has received. On its own, it possesses nothing but the empty forms of its own operation. Completely pure rational cognition gives us in fact only four things, the very metalogical truths.

Il ne nous est pas parmi de parler de raison absolue, et il n'existe pas plus une raison en général qu'il n'existe un triangle en général, si ce n'est sous forme de raison abstraite, obtenue discursivement par la pensée et qui, à titre de représentation extraite d'une représentation, n'est qu'un moyen d'embrasser par l'esprit beaucoup de chose en une seule

Logika doprowadzi? mo?e jedynie do formalnej prawdy, nie za? materialnej.

do nauki tej nale?? ogólne prawa myÅ›lenia, którym rozum podlega w chwili, gdy jest pozostawiony samemu sobie, gdy nic mu nie przeszkadza, a wiÄ™c podczas samotnego myÅ›lenia rozumnej istoty, której nic w bÅ'Ä…d nie wprowadza