popper-logic-scientific-discovery

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some structural components of a theory of experience
age-old corpuscular theory of light; the fluid-theory of electricity
(revived as the electron-gas hypothesis of metallic conduction). All
these metaphysical concepts and ideas may have helped, even in their
early forms, to bring order into man’s picture of the world, and in
some cases they may even have led to successful predictions. Yet an idea
of this kind acquires scientific status only when it is presented in falsifiable
form; that is to say, only when it has become possible to decide
empirically between it and some rival theory.
My investigation has traced the various consequences of the
decisions and conventions—in particular of the criterion of
demarcation—adopted at the beginning of this book. Looking back,
we may now try to get a last comprehensive glimpse of the picture of
science and of scientific discovery which has emerged. (What I have
here in mind is not a picture of science as a biological phenomenon, as
an instrument of adaptation, or as a roundabout method of production:
I have in mind its epistemological aspects.)
Science is not a system of certain, or well-established, statements;
nor is it a system which steadily advances towards a state of finality.
Our science is not knowledge (epistēmē): it can never claim to have
attained truth, or even a substitute for it, such as probability.
Yet science has more than mere biological survival value. It is not
only a useful instrument. Although it can attain neither truth nor probability,
the striving for knowledge and the search for truth are still the
strongest motives of scientific discovery.
We do not know: we can only guess. And our guesses are guided by the
unscientific, the metaphysical (though biologically explicable) faith in
laws, in regularities which we can uncover—discover. Like Bacon, we
might describe our own contemporary science—‘the method of reasoning
which men now ordinarily apply to nature’—as consisting of
‘anticipations, rash and premature’ and of ‘prejudices’. 1
But these marvellously imaginative and bold conjectures or ‘anticipations’
of ours are carefully and soberly controlled by systematic tests.
Once put forward, none of our ‘anticipations’ are dogmatically upheld.
Our method of research is not to defend them, in order to prove how
1 Bacon, Novum Organum I, 26.