popper-logic-scientific-discovery

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some structural components of a theory of experience
are placed in a new light by our examination of degrees of falsifiability,
as we shall see; especially the problem of the so-called ‘probability of
hypotheses’ or of corroboration.
Addendum, 1972
One of the more important ideas of this book is that of the (empirical,
or informative) content of a theory. (‘Not for nothing do we call the
laws of nature “laws”: the more they prohibit, the more they say.’ Cp.
pp. 18–19 above, and pp. 95 f.)
Two points were stressed by me in the preceding chapter: (1) The
content or the testability (or the simplicity: see ch. vii) of a theory may
have degrees, which may thus be said to relativize the idea of falsifiability
(whose logical basis remains the modus tollens). (2) The aim of science—
the growth of knowledge—can be identified with the growth
of the content of our theories. (See my paper ‘The Aim of Science’,
in Ratio I, 1957, pp. 24–35 and (revised) in Contemporary Philosophy, ed.
R. Klibansky, 1969, pp. 129–142; now also Chapter 5 of my book
Objective Knowledge: An Evolutionary Approach, which is forthcoming at
the Clarendon Press.)
More recently I have developed these ideas further; see especially ch.
10 of my Conjectures and Refutations, 1963 and later editions (with the new
Addenda). Two of the new points are: (3) A further relativization of the
idea of content or testability with respect to the problem, or set of problems,
under discussion. (Already in 1934 I relativized these ideas with
respect to a field of application; see my old Appendix i.) (4) The
introduction of the idea of the truth content of a theory and of its
approximation or nearness to truth (‘verisimilitude’).