Karl Popper Quotes

Facts are not truths; they are not conclusions; they are not even premises, but in the nature and parts of premises.

However logical our induction, the end of the thread is fastened upon the assurance of faith.

Induction is a process of inference; it proceeds from the known to the unknown.

God forbid that Truth should be confined to Mathematical Demonstration!

It will never be possible by pure reason to arrive at some absolute truth.

To invent without scruple a new principle to every new phenomenon, instead of adapting it to the old; to overload our hypothesis with a variety of this kind, are certain proofs that none of these principles is the just one, and that we only desire, by a number of falsehoods, to cover our ignorance of the truth.

Truth has nothing to do with the conclusion, and everything to do with the methodology.

A science is something which is constructed from truth on workable axioms. There are 55 axioms in scientology which are very demonstrably true, and on these can be constructed a great deal.

Validity is the touchstone of inference, and truth of judgment: the fact that vichyssoise is cold ratifies the judgment that vichyssoise is, indeed, cold, and the judgment that vichyssoise is cold expresses the fact that vichyssoise is cold.

My father, whose way was to force every event in nature into an hypothesis, by which means never man crucified TRUTH at the rate he did.

In disquisitions of every kind there are certain primary truths, or first principles, upon which all subsequent reasoning must depend.

If someone doesn’t value evidence, what evidence are you going to provide that proves they should value evidence. If someone doesn’t value logic, what logical argument would you invoke to prove they should value logic?

Until the seventeenth century there was no concept of evidence with which to pose the problem of induction!

Rationality is the recognition of the fact that nothing can alter the truth and nothing can take precedence over that act of perceiving it.

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.

The scientist believes in proof without certainty.

Arithmetic is where the content lies, and not logic; but logic prompts certainty, and not arithmetic.

As in Mathematicks, so in Natural Philosophy, the Investigation of difficult Things by the Method of Analysis, ought ever to precede the Method of Composition. This Analysis consists in making Experiments and Observations, and in drawing general Conclusions from them by Induction, and admitting of no Objections against the Conclusions, but such as are taken from Experiments, or other certain Truths. For Hypotheses are not to be regarded in experimental Philosophy.

In the philosophic sense, observation shows and experiment teaches.

Our reasonings are grounded upon two great principles, that of contradiction, in virtue of which we judge false that which involves a contradiction, and true that which is opposed or contradictory to the false.

What can give us more sure knowledge than our senses? How else can we distinguish between the true and the false?

The so-called law of induction cannot possibly be a law of logic, since it is obviously a proposition with a sense.--Nor, therefore, can it be an a priori law.

Through logic and inference we can prove anything. Therefore, logic and inference, in contrast to ordinary daily living experience, are secondary instruments of knowledge. Probably tertiary.

If scientific reasoning were limited to the logical processes of arithmetic, we should not get very far in our understanding of the physical world