It is easy to obtain confirmations, or verifications, for nearly every theory-if we look for confirmations. Confirmations should count only if they are the result of risky predictions... 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. Every genuine test of a theory is an attempt to falsify it, or refute it.
Interpretation
The quote emphasizes the importance of falsifiability in scientific theories over mere confirmations.
Karl Popper argues that a scientific theory must be falsifiable, meaning that it should be possible to conceive an event that would prove it wrong. Merely finding confirmations for a theory does not validate it; rather, the strength of a scientific theory lies in its ability to withstand rigorous testing and the potential to be disproven.
In practice
During a lecture on scientific methodology, one can use this quote to illustrate the core principle of falsifiability.
The growth of our knowledge is the result of a process closely resembling what Darwin called 'natural selection'; that is, the natural selection of hypotheses: our knowledge consists, at every moment, of those hypotheses which have shown their (comparative) fitness by surviving so far in their struggle for existence, a competitive struggle which eliminates those hypotheses which are unfit.
If you can't say it simply and clearly, keep quiet, and keep working on it till you can.
No particular theory may ever be regarded as absolutely certain.... No scientific theory is sacrosanct.
The belief in a political Utopia is especially dangerous. This is possibly connected with the fact that the search for a better world, like the investigation of our environment, is (if I am correct) one of the oldest and most important of all the instincts.
A rationalist is simply someone for whom it is more important to learn than to be proved right; someone who is willing to learn from others - not by simply taking over another's opinions, but by gladly allowing others to criticize his ideas and by gladly criticizing the ideas of others
Thus science must begin with myths, and with the criticism of myths; neither with the collection of observations, nor with the invention of experiments, but with the critical discussion of myths, and of magical techniques and practices.
The feeling is constantly growing on me that I had been the first to hear the greeting of one planet to another.
In summoning even the wisest of physicians to our aid, it is probably that he is relying upon a scientific "truth", the error of which will become obvious in just a few years' time.
Science demands from a man all his life. If you had two lives that would not be enough for you. Be passionate in your work and in your searching.
Well-established theories collapse under the weight of new facts and observations which cannot be explained, and then accumulate to the point where the once useful theory is clearly obsolete.
Evolution has encountered no intellectual trouble; no new arguments have been offered. Creationism is a home-grown phenomenon of American sociocultural history-a splinter movement ... who believe that every word in the Bible must be literally true, whatever such a claim might mean.
Medical science has proven time and again that when the resources are provided, great progress in the treatment, cure, and prevention of disease can occur.
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