No particular theory may ever be regarded as absolutely certain.... No scientific theory is sacrosanct.
Interpretation
Scientific theories are provisional and subject to change rather than being seen as absolute truths.
In this quote, Karl Popper emphasizes the idea that scientific theories should not be considered as definitive truths. Instead, they are always open to questioning, revision, and falsification. This notion highlights the dynamic and evolving nature of scientific inquiry, suggesting that the pursuit of knowledge is an ongoing process rather than a conclusion to be firmly established.
In practice
In a science class discussing the nature of scientific theories.
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.
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.
I am opposed to looking upon logic as a kind of game. ... One might think that it is a matter of choice or convention which logic one adopts. I disagree with this view.
We scientists have fantasies of being uniquely qualified to make great discoveries. Alas, reality is cruel: most of us are replaceable. For the vast majority of scientific contributions, if scientist X hadn't achieved it that year, scientist Y would have achieved the same result or something very similar soon thereafter.
Economics profession, they've been - they've been confident in various formulas, but economics is not physics. The same formula that works in one decade doesn't work in the next. Economics is a difficult subject.
... chemistry is a trade for people without enough imagination to be physicists.
Mathematics is one of the deepest and most powerful expressions of pure human reason, and, at the same time, the most fundamental resource for description and analysis of the experiential world.
At the last dim horizon, we search among ghostly errors of observations for landmarks that are scarcely more substantial. The search will continue. The urge is older than history. It is not satisfied and it will not be oppressed.
There is no such thing as a special category of science called applied science; there is science and its applications, which are related to one another as the fruit is related to the tree that has borne it.
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