Karl Popper Quotes

A good scientific theory is one which is falsifiable, which has not been falsified.

No amount of experimentation can ever prove me right; a single experiment can prove me wrong.

Science does not limit itself merely to what is currently verifiable. But it is interested in questions that are potentially verifiable (or, rather, falsifiable).

Everything that people say is testable.

Falsifiability for a theory is great, but a theory can still be respectable even if it is not falsifiable, as long as it is verifiable.

Science is constantly proved all the time. If we take something like any fiction, any holy book, and destroyed it, in a thousand years' time, that wouldn't come back just as it was. Whereas if we took every science book and every fact and destroyed them all, in a thousand years they'd all be back because all the same tests would be the same result.

Science is defined in various ways, but today it is generally restricted to something which is experimental, which is repeatable, which can be predicted, and which is falsifiable.

The criterion of the scientific status of a theory is its falsifiability, or refutability, or testability.

Maybe scientists are fundamentalist when it comes to defining in some abstract way what is meant by 'truth'. But so is everybody else. I am no more fundamentalist when I say evolution is true than when I say it is true that New Zealand is in the southern hemisphere. We believe in evolution because the evidence supports it, and we would abandon it overnight if new evidence arose to disprove it.

In science, if an idea is not falsifiable, it is not that it is wrong, it is that we cannot determine if it is wrong, and thus it is not even wrong.

A theory which is not refutable by any conceivable event is non-scientific. Irrefutability is not a virtue of a theory (as people often think) but a vice.

There can be no ultimate statements science: there can be no statements in science which can not be tested, and therefore none which cannot in principle be refuted, by falsifying some of the conclusions which can be deduced from them.

It must be possible for an empirical system to be refuted by experience.

It is certainly not the least charm of a theory that it is refutable.

A system is empirical or scientific only if it is capable of being tested by experience. These considerations suggest that not the verifiability but the falsifiability of a system is to be taken as a criterion of demarcation... It must be possible for an empirical or scientific system to be refuted by experience.

Every theory presented as a scientific concept is just that; it's a theory that tries to explain more about the world than previous theories have done. It is open to being challenged and to being proven incorrect.

A valid scientific theory is predictive, verifiable, and replicable. To me, that's beautiful.

Science has authority, not because of white coats, or titles, but because of precision and transparency: you explain your theory, set out your evidence, and reference the studies that support your case.

Science has faith. We make postulates. We can't prove those postulates, but we have faith in them.

Where we have good, testable explanations, they then have to be tested, and we drop the ones that fail the tests.

One of the distinguishing features of anything that aspires to the name of science is the reproducibility of experimental results.

In nature, when you conduct science, it is the natural world that is the ultimate decider in what is true and what is not.

Theorists can be wrong; only nature is always right.

I can assure you that no string theorist would be interested in working on string theory if it were somehow permanently beyond testability. That would no longer be doing science.

My background is basically scientific math. My Dad was a physicist, so I have it in my blood somewhere. Scientific method is very important to me. I think anything that contradicts it is probably not true.