Karl Popper held that the effort of reaching a preference of one theory against others is the key to escaping the trap of the logical error of induction. This position is not a late appendage but is clearly stated for the English-speaking world in “The Logic of Scientific Discovery” (1959), the translated version of “Logik der Forschung” (1934). In Paul Arthur Schilpp’s “Philosophy of Karl Popper” (1974) Volume 2 Popper replies to his critics and gives credit for the fine-tuning of his comments to his associate David Miller. On Page 52 of his own book “Critical Rationalism a Restatement and Defence” (1994), Miller states: “There are no such things as good reasons; that is, sufficient or even partly sufficient favourable (or positive) reasons for accepting a hypothesis rather than rejecting it, or for rejecting it rather than accepting it, or for implementing a policy, or for not doing so”. Miller seems to be addressing reasons that are not critical preferences.
Thomas Stearn Eliot’s much quoted paragraph from “Four Quartets”, “Little Gidding” (1942), echoes my experience when reading Popper:
“We shall not cease from exploration
And the end of all our exploring
Will be to arrive where we started
And know the place for the first time.”
The quest for certainty in 20th and now 21st century philosophy is unfortunately given an epistemic significance that fills volume after volume but leads to no escape from Hume’s problem of induction nor Kant’s problem of demarcation. Relegating Popper to footnotes or comfortable low rungs in textbook chapter organization does not help this quest and, even worse, the strawman naive-falsificationist legend of Popper actually hinders it.
The extract, below, from “The Logic of Scientific Discovery” highlights Popper’s understanding of the problem of the empirical basis in that acceptance of evidence (basic statements) is the result of human decisions, agreements. Science is a human activity, indeed a communal activity. What decides the fate of a theory is decisions not on aesthetic considerations such as how simple (Occam’s Razor) the theory is worded but decisions on what basic statements are to be accepted for attempted rebuttal of theories. The value of simplicity is to improve testability. One must also differentiate between existential trends e.g. statistical samples of events and so-called probability of hypotheses. Popper rejects the latter.
In the 1963 essay “Models Instruments and Truth”, included in the anthology”The Myth of the Framework” (1994) Popper is critical of the ridiculous phrase “truth is relative”. This phrase confuses the choice we make relative to competing theories’ perceived closeness to truth with TRUTH, unsullied by our opinions and efforts. No matter how well we test our theories they may still not be fair reflections of reality.
In the “The Logic of Scientific Discovery” (1959 orig., ninth impression July 1977, Hutchinson & Co, London), Page 108 – Section 30, “Theory and Experiment” Popper states:
“It may now be possible for us to answer the question: How and why do we accept one theory in preference to others?
The preference is certainly not due to anything like an experiential justification of the statements composing the theory; it is not due to a logical reduction of the theory to experience. We choose the theory which best holds its own in competition with other theories; the one which, by natural selection, proves itself the fittest to survive. This will be the one which not only has hitherto stood up to the severest tests, but the one which is also testable in the most rigorous way. A theory is a tool which we test by applying it, and which we judge as to its fitness by the results of its applications.
From a logical point of view, the testing of a theory depends upon basic statements whose acceptance or rejection, in its turn, depends upon our decisions. Thus it is decisions which settle the fate of theories. To this extent my answer to the question, ‘how do we select a theory?’ resembles that given by the conventionalist; and like him I say that this choice is in part determined by considerations of utility. But in spite of this, there is a vast difference between my views and his. For I hold that what characterizes the empirical method is just this: that the convention or decision does not immediately determine our acceptance of universal statements but that, on the contrary, it enters into our acceptance of the singular statements – that is, the basic statements.
For the conventionalist, the acceptance of universal statements is governed by his principle of simplicity: he selects that system which is the simplest. I, by contrast, propose that the first thing to be taken into account should be the severity of tests. (There is a close connection between what I call ‘simplicity’ and the severity of tests; yet my idea of simplicity differs widely from that of the conventionalist; see section 46.) And I hold that what ultimately decides the fate of a theory is the result of a test, i.e. an agreement about basic statements. With the conventionalist I hold that the choice of any particular theory is an act, a practical matter. But for me the choice is decisively influenced by the application of the theory and the acceptance of the basic statements in connection with this application; whereas for the conventionalist, aesthetic motives are decisive.
Thus I differ from the conventionalist in holding that the statements decided by agreement are not universal but singular. And I differ from the positivist in holding that basic statements are not justifiable by our immediate experiences, but are, from the logical point of view, accepted by an act, by a free decision. (From the psychological point of view this may perhaps be a purposeful and well-adapted reaction.)”
For those interested, some further references in his works can be found as follows:
“After the Open Society” (2008), page 10 “Optimist,Pessimist and Pragmatist Views of Scientific Knowledge” (1963)
“The Myth of the Framework” (1994), Models, Instruments and Truth (orig 1963)
“Conjectures and Refutations” (1963), Page 235 – Chapter 10 Truth, Rationality, and the Growth of Knowledge, XIII
Page 248 – XXII
“Objective Knowledge” (1972)
Page 20 – Chapter 1. Conjectural Knowledge, Section 8 Corroboration: The Merits of Improbability
“Realism and the Aim of Science” (1983)
Page 65 – Chapter 1 Induction, Section 4 A Family of Four Problems III
page 71 Chapter 1 Induction, Section 4 A Family of Four Problems VI
“Unended Quest” (1974), standalone printing. Unended Quest is the autobiography included in the two volume Schilpp “The Philosophy of Karl Popper”
P. A. Schilpp, “The Philosophy of Karl Popper” (1974)
Page 1024 + Replies to My Critics -Section 14 The Psychological and Pragmatic Problems of Induction