On my revisiting “Realism and the Aim of Science: from the Postscript to the Logic of Scientific Discovery” (1983), written around 1951-56, it is apparent that the concept of critical preference is emphasized. In considering falsifiability and falsification in isolation one might miss this.
Popper says (p65), of course we expect the sun to rise tomorrow because it is the best theory available. “Best available theory” means in comparison with other theories.
The action of comparing theories with other theories is critical. Popper (p71) replaces the problem “How do you know? What is the reason or justification, for your assertion?” by the problem: “Why do you prefer this conjecture to competing conjectures? What is the reason for your preference?”
Corroboration reports on the survival after testing. Popper was never simplistic and proposed that one might consider:
internal consistency in comparing conclusions,
investigations of the logical forms of theories,
comparing theories with other theories to determine whether or not the theory under consideration is a scientific advance,
and empirical applications of the conclusions.
Even a simplistic assertion, that the sun will rise tomorrow, can be contrasted with an alternative, the sun will not rise tomorrow. The rising of the sun as observed by humans for thousands of years corroborates the hypothesis that the sun will always rise, in non-polar latitudes, but we do not propose that the sun will always rise just because it rose before.
The expectation that the sun will not rise is not as acceptable because
1. non-rising has failed observational testing, and
2. there are arguments that are less strong in supporting non-rising rather than rising, for now.
ExACTly!! — Frank
To elaborate on the above post:
“Realism and the Aim of Science: from the Postscript to the Logic of Scientific Discovery” (1983), was written in draft form around 1951-56. W.W. Bartley finally helped Popper bring it to print.
It could be enlightening reading for students of the philosophy of science, one reason being that in the introduction Popper addresses Kuhn’s paradigm of Popper – the enduring myth in textbooks that Popper was a naive falsificationist. Textbooks are usually built on convenient ladder rungs but the weakness of the falsificationist rung has been extraordinary with respect to Popper. Even a cursory reading of “The Logic of Scientific Discovery” (1959, in German “Logik der Forschung” 1934, imprint 1935) would have dispelled this myth but recent textbooks of philosophy of science continue to propagate it. A fashion or paradigm indeed.
Returning to page 71:
The problem “How do you know? What is the reason or justification, for your assertion?”, is replaced by the problem: “Why do you prefer this conjecture to competing conjectures? What is the reason for your preference?”
“While my answer to the first question is “I do not know”, my answer to the second problem is that, as a rule our preference for a better corroborated theory will be defended rationally by those arguments which have been used in our critical discussion, including of course our discussion of the results of tests. These are the arguments of which the degree of corroboration is intended to provide a summary report.
In this way the logical problem of induction is solved.”