505 Logic Quotes

Do not imagine that mathematics is hard and crabbed, and repulsive to common sense. It is merely the etherealization of common sense.

People must not do things for fun. We are not here for fun. There is no reference to fun in any Act of Parliament.

You can't have it both ways. Either our rights come from God, as our Declaration of Independence says, or they come from human choice. If they come from human choice, then our whole way of life is meaningless, it has no foundation.

What must be remembered in any case is that secret complicity that joins the logical and the everyday to the tragic.

Caution! Be very careful of false, meaningless, self-contradictory, and not even very funny warnings, like this one.

Every philosophical problem, when it is subjected to the necessary analysis and justification, is found either to be not really philosophical at all, or else to be, in the sense in which we are using the word, logical.

In a logically perfect language, there will be one word and no more for every simple object, and everything that is not simple will be expressed by a combination of words, by a combination derived, of course, from the words for the simple things that enter in, one word for each simple component.

A great part of its theories derives an additional charm from the peculiarity that important propositions, with the impress of simplicity on them, are often easily discovered by induction, and yet are of so profound a character that we cannot find the demonstrations till after many vain attempts; and even then, when we do succeed, it is often by some tedious and artificial process, while the simple methods may long remain concealed.

I mean the word proof not in the sense of the lawyers, who set two half proofs equal to a whole one, but in the sense of a mathematician, where half proof = 0, and it is demanded for proof that every doubt becomes impossible.

When a philosopher says something that is true then it is trivial. When he says something that is not trivial then it is false.

I don't like spinach, and I'm glad I don't, because if I liked it I'd eat it, and I just hate it.

Reason, it is true, is DICTATOR in the Society of Mankind; from her there ought to lie no Appeal; But here we want a Pope in our Philosophy, to be the infallible Judge of what is or is not Reason.

To prove the Gospels by a miracle is to prove an absurdity by something contrary to nature.

In order to shake a hypothesis, it is sometimes not necessary to do anything more than push it as far as it will go.

Reality trumps rationality.

If your parents never had children, chances are you won't either.

The sun comes up just about as often as it goes down, in the long run, but this doesn't make its motion random.

Woman's inaptitude for reasoning has not prevented her from arriving at truth; nor has man's ability to reason prevented him from floundering in absurdity.

We all dream; we do not understand our dreams, yet we act as if nothing strange goes on in our sleep minds, strange at least by comparison with the logical, purposeful doings of our minds when we are awake.

Metaphysics is the finding of bad reasons for what we believe upon instinct; but to find these reasons is no less an instinct.

Aristotle... a mere bond-servant to his logic, thereby rendering it contentious and well nigh useless.

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.

Since my logic aims to teach and instruct the understanding, not that it may with the slender tendrils of the mind snatch at and lay hold of abstract notions (as the common logic does), but that it may in very truth dissect nature, and discover the virtues and actions of bodies, with their laws as determined in matter; so that this science flows not merely from the nature of the mind, but also from the nature of things.

If what was supposed to have been destroyed in Paradise was destructible, then it was not decisive; but if it was indestructible, then we are living in a false belief.

In argument similes are like songs in love; they describe much, but prove nothing.

The bottom line for mathematicians is that the architecture has to be right. In all the mathematics that I did, the essential point was to find the right architecture. It's like building a bridge. Once the main lines of the structure are right, then the details miraculously fit. The problem is the overall design.

Well, if crime fighters fight crime and fire fighters fight fire, what do freedom fighters fight? They never mention that part to us, do they?

If the Cincinnati Reds were really the first major league baseball team, who did they play?

Almost every wise saying has an opposite one, no less wise, to balance it.

It is only the inferior thinker who hastens to explain the singular and the complex by the primitive shortcut of supernaturalism.

I found it peculiar that those who wanted to take military action could - with 100 per cent certainty - know that the weapons existed and turn out to have zero knowledge of where they were.

It's true the Iraqis misbehaved and had no credibility but that doesn't necessarily mean that they were in the wrong.

Diderot took the ground that, if orthodox religion be true Christ was guilty of suicide. Having the power to defend himself he should have used it.

I never said all Democrats were saloonkeepers; what I said was that all saloonkeepers are Democrats.

My father was never proud of me. One day he asked me, 'How old are you?' I said, 'I'm five.' He said, 'When I was your age, I was six.'

I am not keeping back facts. Every fact that I know is in your possession. You can draw your own deductions from them.

The impossible could not have happened, therefore the impossible must be possible in spite of appearances.

Exactly! It is absurd - improbable - it cannot be. So I myself have said. And yet, my friend, there it is! one cannot escape from the facts.

None of the Marxist concepts (literally - not a single one!) matches the logical rules of scientific concepts.

Philosophy, in one of its functions, is the critic of cosmologies. It is its function to harmonise, refashion, and justify divergent intuitions as to the nature of things. It has to insist on the scrutiny of the ultimate ideas, and on the retention of the whole of the evidence in shaping our cosmological scheme. Its business is to render explicit, and - so far as may be - efficient, a process which otherwise is unconsciously performed without rational tests.

Rationalism is an adventure in the clarification of thought.

The term many presupposes the term one, and the term one presupposes the term many.

Absurdity, n. A statement or belief manifestly inconsistent with one's own opinion.

Brain, n. An apparatus with which we think what we think.

Logic, n. The art of thinking and reasoning in strict accordance with the limitations and incapacities of the human misunderstanding.

Certain old men prefer to rise at dawn, taking a cold bath and a long walk with an empty stomach and otherwise mortifying the flesh. They then point with pride to these practices as the cause of their sturdy health and ripe years; the truth being that they are hearty and old, not because of their habits, but in spite of them. The reason we find only robust persons doing this thing is that it has killed all the others who have tried it.

The want of logic annoys. Too much logic bores. Life eludes logic, and everything that logic alone constructs remains artificial and forced.

'Therefore' is a word the poet must not know.

Philosophy ... is a science, and as such has no articles of faith; accordingly, in it nothing can be assumed as existing except what is either positively given empirically, or demonstrated through indubitable conclusions.

We used to think that if we knew one, we knew two, because one and one are two. We are finding that we must learn a great deal more about 'and'.

Those who deny the first principle should be flogged or burned until they admit that it is not the same thing to be burned and not burned, or whipped and not whipped.

The right honourable gentleman [Sir Robert Peel] tells us to go back to precedents; with him a great measure is always founded on a small precedent. He traces the steam-engine always back to the tea-kettle. His precedents are generally tea-kettle precedents.

A sophistical rhetorician, inebriated with the exuberance of his own verbosity who can at all times command an interminable and inconsistent series of arguments to malign an opponent and glorify himself.

Gates is the ultimate programming machine. He believes everything can be defined, examined, reduced to essentials, and rearranged into a logical sequence that will achieve a particular goal.

Then comes the kicker: Say the alphabet : backwards. 'Well, shoot, you got me. I'm not drunk, but I'm obviously too stupid to be driving, God damn it.'

'Today a young man on acid, thought he could fly, jumped off a building, what a tragedy.' What a dick! If he thought he could fly, why didn't he take off from the ground?

The word generalization in literature usually means covering too much territory too thinly to be persuasive, let alone convincing. In science, however, a generalization means a principle that has been found to hold true in every special case. ... The principle of leverage is a scientific generalization.

You either make sense or you make money.

I am trying here to prevent anyone saying the really foolish thing that people often say about Him: 'I'm ready to accept Jesus as a great moral teacher, but I don't accept His claim to be God.' That is the one thing we must not say. A man who was merely a man and said the sort of things Jesus said would not be a great moral teacher. He would be either a lunatic - on a level with the man who says he is a poached egg - or else he would be the Devil of Hell. You must make your choice. Either this man was, and is, the Son of God: or else a madman or something worse. You can shut Him up for a fool, you can spit at Him and kill Him as a demon; or you can fall at His feet and call Him Lord and God. But let us not come with any patronising nonsense about His being a great human teacher. He has not left that open to us. He did not intend to.

'By the Lion's Mane, a strange device,' said King Peter, 'to set a lantern here where the trees cluster so thick about it and so high above it that if it were lit it should give light to no man!' (ch. 17)

But always what we have taken in hand, the same we have achieved. (ch. 17)

'A few months ago they [the Duffers] were all for washing up the plates and knives before dinner: they said it saved time afterwards. I've caught them planting boiled potatoes to save cooking them when they were dug up. One day the cat got into the dairy and twenty of them were at work moving all the milk out; no one thought of moving the cat.' (ch. 11)

There is an inconvenience which attends all abstruse reasoning. that it may silence, without convincing an antagonist, and requires the same intense study to make us sensible of its force, that was at first requisite for its invention. When we leave our closet, and engage in the common affairs of life, its conclusions seem to vanish, like the phantoms of the night on the appearance of the morning; and 'tis difficult for us to retain even that conviction, which we had attain'd with difficulty.

When we run over libraries, persuaded of these principles, what havoc must we make? If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: For it can contain nothing but sophistry and illusion.

The same good sense, that directs men in the ordinary occurrences of life, is not hearkened to in religious matters, which are supposed to be placed altogether above the cognizance of human reason.

In such a chain, too, or succession of objects, each part is caused by that which preceded it, and causes that which succeeds it. Where then is the difficulty? But the WHOLE, you say, wants a cause. I answer, that the uniting of these parts into a whole, like the uniting of several distinct countries into one kingdom, or several distinct members into one body, is performed merely by an arbitrary act of the mind, and has no influence on the nature of things. Did I shew you the particular causes of each individual in a collection of twenty particles of matter, I should think it very unreasonable, should you afterwards ask me, what was the cause of the whole twenty. This is sufficiently explained in explaining the cause of the parts.

I'm a bit of a deconstructionist myself. It's kind of exciting - the last intellectual thrill left. Like sawing through the branch you're sitting on.

'Hi! I'm Crazy Eddie! I put babies on spikes. Do you want a rack of babies? We've got babies on racks! Mmm, they taste of chicken!' They do! Babies taste of chicken! Cannibals say that human flesh tastes of chicken, so babies must taste of chicken. And chicken tastes of humans. Good, I'm glad you're coming with me on that.

She said, 'Spell 'ant'', and I wrote out the entire alphabet. She said, 'That doesn't spell 'ant'', and I said, 'It's in there somewhere! There's the 'A', there's the 'N', there's the 'T' - the rest are silent!'

I'll not listen to reason:Reason always means what someone else has got to say.

I didn't mean you were stupid. It's just that you're not logical, which isn't the same thing at all.

Logician: A cat has four paws. Old Gentleman: My dog had four paws. Logician: Then it's a cat. Old Gentleman: So my dog is a cat? Logician: And the contrary is also true.

[It is anomalous] to hold that in order to convict a man the police cannot extract by force what is in his mind, but can extract what is in his stomach.

Answers are not obtained by putting the wrong question and thereby begging the real one.

And as well as I dream, I reason if I want, for that's just another kind of dream.

L'esprit est toujours la dupe du coeur.

We must question the story logic of having an all-knowing all-powerful God, who creates faulty Humans, and then blames them for his own mistakes.

Groucho: Would you mind getting up off of that fly paper and giving the flies a chance? Chico: Flies can't read papers.

A black cat crossing your path signifies that the animal is going somewhere.

I'm not a vegetarian, but I eat animals who are.

When a person's nose itches, it is a sign that it should be scratched.

A Jewish woman had 2 chickens. One got sick, so the woman made chicken soup out of the other one to help the sick one get well.

Some circumstantial evidence is very strong, as when you find a trout in the milk.

It is remarkable that, notwithstanding the universal favor with which the New Testament is outwardly received, and even the bigotry with which it is defended, there is no hospitality shown to, there is no appreciation of, the order of truth with which it deals.

Distinction without a difference.

Fallacious and misleading arguments are most easily detected if set out in correct syllogistic form.

Bob Crosby: That's like keeping the smog and throwing away Los Angeles.

Jack Benny: Does it have to be both?

Well, if I called the wrong number, why did you answer the phone?

One of the characteristics of the dream is that nothing surprises us in it. With no regret, we agree to live in it with strangers, completely cut off from our habits and friends.

If we understood the world, we would realize that there is a logic of harmony underlying its manifold apparent dissonances.

The book, as it stands, seems to me to be one of the most frightful muddles I have ever read, with scarcely a sound proposition in it beginning with page 45 [Hayek provided historical background up to page 45; after that came his theoretical model], and yet it remains a book of some interest, which is likely to leave its mark on the mind of the reader. It is an extraordinary example of how, starting with a mistake, a remorseless logician can end up in bedlam.