Logic Quotes

500+ Sourced quotes

I am allowed to use plain English because everybody knows that I could use mathematical logic if I chose.

Bertrand Russell

I think all the great religions of the world - Buddhism, Hinduism, Christianity, Islam, and Communism - both untrue and harmful. It is evident as a matter of logic that, since they disagree, not more than one of them can be true. With very few exception, the religions which a man accepts is that of the community in which he lives, which makes it obvious that the influence of environment is what has led him to accept the religion in question.

Bertrand Russell

The logic now in use serves rather to fix and give stability to the errors which have their foundation in commonly received notions than to help the search for truth. So it does more harm than good.

That Logic has advanced in this sure course, even from the earliest times, is apparent from the fact that, since Aristotle, it has been unable to advance a step, and thus to all appearance has reached its completion.

The seed haunted by the sun never fails to find its way between the stones in the ground. And the pure logician, if no sun draws him forth, remains entangled in his logic.

Antoine de Saint-Exupéry

Modern science cares far less for pure logic than a dancing Dervish.

G. K. Chesterton

Logic is concerned with the real world just as truly as zoology [is].

Bertrand Russell

"I know what you're thinking about," said Tweedledum; "but it isn't so, nohow." "Contrariwise," continued Tweedledee, "if it was so, it might be; and if it were so, it would be; but as it isn't, it ain't. That's logic."

Men are rather beholden...generally to chance or anything else, than to logic, for the invention of arts and sciences.

SIMPLICO: Indeed, I begin to understand that while logic is an excellent guide in discourse, it does not, as regards stimulation to discovery, compare with the power of sharp distinction which belongs to geometry.

Galileo Galilei

Inferences of Science and Common Sense differ from those of deductive logic and mathematics in a very important respect, namely, when the premises are true and the reasoning correct, the conclusion is only probable.

Bertrand Russell

For nothing is more democratic than logic; it is no respecter of persons and makes no distinction between crooked and straight noses.

Friedrich Nietzsche

When I come upon anything-in Logic or in any other hard subject-that entirely puzzles me, I find it a capital plan to talk it over, aloud, even when I am all alone. One can explain things so clearly to one's self! And then, you know, one is so patient with one's self: one never gets irritated at one's own stupidity!

Ivan Ilych saw that he was dying, and he was in continual despair. In the depth of his heart he knew he was dying, but not only was he not accustomed to the thought, he simply did not and could not grasp it. The syllogism he had learnt from Kiesewetter's Logic: "Caius is a man, men are mortal, therefore Caius is mortal," had always seemed to him correct as applied to Caius, but certainly not as applied to himself. That Caius — man in the abstract — was mortal, was perfectly correct, but he was not Caius, not an abstract man, but a creature quite, quite separate from all others.

Rhetoric is the counterpart of logic; since both are conversant with subjects of such a nature as it is the business of all to have a certain knowledge of, and which belong to no distinct science. Wherefore all men in some way participate of both; since all, to a certain extent, attempt, as well to sift, as to maintain an argument; as well to defend themselves, as to impeach.

Every man should have aunts. They illustrate the triumph of guesswork over logic.

Agatha Christie

Logic differeth from rhetoric as the fist from the palm; the one close, the other at large.

Each word of Heraclitus expresses the pride and the majesty of truth, but of truth grasped in intuitions rather than attained by the rope ladder of logic.

Friedrich Nietzsche

The conflicts that tear society apart resemble the distinction between the concept and the particular facts subordinated to it.... Whatever refuses to abide by the unity imposed by the principle of dominion manifests itself not as something indifferent to that principle, but as an infringement of logic: as a contradiction.

Theodor W. Adorno

Cimourdain was one of those men who have a voice within them, and who listen to it. Such men seem absent-minded; they are not; they are all attention.
Cimourdain knew everything and nothing. He knew everything about science, and nothing at all about life. Hence his inflexibility. His eyes were bandaged like Homer's Themis. He had the blind certainty of the arrow, which sees only the mark and flies to it. In a revolution, nothing is more terrible than a straight line. Cimourdain went straight ahead, as sure as fate.
Cimourdain believed that, in social geneses, the extreme point is the solid earth; an error peculiar to minds which replace reason with logic.

If Nietzsche and Hegel serve as alibis to the masters of Dachau and Karaganda, that does not condemn their entire philosophy. But it does lead to the suspicion that one aspect of their thought, or of their logic, can lead to these appalling conclusions.

The mathematics are the science of form and quantity, mathematical reasoning is merely logic applied to observation upon form and quantity.

Edgar Allan Poe

Logic ignores the almost, just as the sun ignores the candle.

Scholars and artists thrown together are often annoyed at the puzzle of where they differ. Both work from knowledge; but I suspect they differ most importantly in the way their knowledge is come by. Scholars get theirs with conscientious thoroughness along projected lines of logic; poets theirs cavalierly and as it happens in and out of books. They stick to nothing deliberately, but let what will stick to them like burrs where they walk in the fields.

Man has such a predilection for systems and abstract deductions that he is ready to distort the truth intentionally he is ready to deny the evidence of his senses only to justify his logic.

Fyodor Dostoyevsky