¹ London 1957; previously published in Economica, N.S., XI (1944)Google Scholar and XII (1945). References to this book will be indicated by PH.

² Fourth (revised) edition, 2 vols., London 1962 (first published in 1945; American edition, Princeton 1950). References are to the fourth edition, and will be indicated by OS. References to the present book will be indicated by CR.

³ They make up about one-fourth of this collection of twenty-one essays and lectures, al except four previously published; the rest of the book deals with often rather technical problems of philosophy of science which arc not likely to be of direct interest to readers of World Politics.

⁴ To the extent that both are compatible, as they are, e.g., in the philosophy of J. S. Mill but not of Rousseau. Popper does not deal with this problem, and I shall disregard it here.

⁵ All except the most extreme empiricists agree with the rationalists that deductive reasoning alone determines the truth of “necessary” propositions, e.g., those of logic and mathematics.

⁶ London 1959; first published in German as Logik der Forschung (Vienna 1935).Google Scholar

⁷ This view implies the necessity of often long, definitional chains between abstract concepts which occur in empirical hypotheses and terms which refer to observables. Yet, Popper himself seems to fall back into naïve empiricism when he rejects as naïve “the theory that the social sciences study the behaviour of social wholes, such as groups, nations, classes, societies, civilizations, etc.” (CR, 341). According to Popper, “these so-called social wholes are very largely postulates of popular social theories rather than empirical objects” (ibid.). He seems to reject the view that they arc scientific constructs, and as such indispensable to the empirical study of social phenomena. Instead, he argues that “the belief in the empirical existence of social wholes or collectives” is a form of “naïve collectivism” (ibid.); but this is plausible only on the view that social wholes constitute organic wholes, which is not implied by viewing these wholes as indispensable constructs.

⁸ “The historicist [asserts] that the variability of historical conditions renders the experimental method inapplicable to the problems of society” (PH, 96).

⁹ Popper docs not claim that the converse implication necessarily holds. Radical historicism leads, not to utopianism, but to fatalism, the view that the necessary course of history can be foreseen, but not influenced by human intervention (OS, 1, 157). Furthermore, historicists often prophesy states of affairs they consider undesirable (e.g., Spengler).

¹⁰ “The Utopian attempt to realize an ideal state, using a blueprint of society as a whole, is one which demands a strong centralized rule of a few, and which therefore is likely to lead to a dictatorship” (OS, 1, 159). “Utopian rationalism is a self-defeating rationalism. However benevolent its ends, it does not bring happiness, but only the familiar misery of being condemned to live under a tyrannical government” (CR, 360).

¹¹ It is the anti-utopianist who disparages a goal as Utopian which he considers, rightly or wrongly, to be unobtainable. Popper, for instance, tends to view all centralized planning as Utopian (cf. OS, 1, 285), which may be due to the influence of F. A. Hayek, to whom CR is dedicated. On the other hand, he believes that the creation of institutions for the prevention of armed aggression, “though often branded as Utopian, is not even a very difficult problem” (OS, 1, 161; this passage still remains in the edition of 1962).

¹² Via “ethical relativism” and “nihilism.” E.g.: “Of the many factors which have contributed to the decline of liberalism in the modern world no single factor has been more important than the rise of positivism and its infiltration into every sphere of thought … Unwittingly, it may be said, such liberals (who were under the influence of positivism) prepared the way for Lidice and Dachau.”—Hallowell, John H., Main Currents in Modern Political Thought (New York 1950), 326.Google Scholar

¹³ Sometimes Popper uses the term even more broadly: “I am a rationalist, and by this I mean that I believe in discussion, and argument” (CR, 337); this “presupposes a certain amount of intellectual humility” (CR, 336), a frame of mind which contrasts rather oddly with Popper's often self-righteous style.

¹⁴ It is, however, not always easy to determine whether the anti-empiricists here referred to would claim that their method for apprehending “truth” is scientific, but non-empirical, or non-scientific—i.e., suprarational. This ambiguity may be found, e.g., in Storing, Herbert J., ed., Essays on the Scientific Study of Politics (New York 1962).Google Scholar

¹⁵ E.g.: “Whatever criticism may be leveled against representative government, its outstanding virtues are bound to make it the point of departure for any social organization safeguarding freedom.”—Mannheim, Karl, Freedom, Power, and Democratic Planning (New York 1950), 149.Google Scholar

¹⁶ “… faith in reason is not only a faith in our own reason, but also—and even more—in that of others. … Rationalism is therefore bound up with the idea that the other fellow has a right to be heard, and to defend his arguments. … Ultimately, in this way, rationalism is linked up with the recognition of the necessity of social institutions to protect freedom of criticism, freedom of thought, and thus freedom of men” (OS, n, 238). The expression “faith in reason” is ambiguous; it could refer either to the belief that objective knowledge is possible or to the view that men tend in fact to avail themselves of this possibility and thus to act reasonably. (Popper connects rationalism in both senses with liberalism.) However, taken in conjunction with the sentence quoted next in the text, it seems more likely that “faith in reason” should here be taken in the second sense.

¹⁷ The normative principle does follow logically from the empirical premise, and jrom the further normative assumption that the extent of anybody's rights ought to be a function of the degree of his rationality. This same normative premise, together with the empirical theory that all except a few are irrational, logically implies the anti-liberal doctrine that these few should have the right to rule over the many. However, most social philosophers deny the further implicit assumption that “degree of rationality” can be operationally defined and objectively determined.

¹⁸ As to the choices of their respective ultimate goals, these cannot be said to be either rational or not, if we agree with Popper that such valuations are a matter of subjective commitment and not of objective knowledge. Utopianism is irrational in this sense; it is irrational to decide to bring about what in fact cannot be realized.

¹⁹ Rationalism in this sense entails epistemological optimism, while anti-rationalism is compatible with both epistemological pessimism and optimism. Both rationalism and anti-rationalism in the present meaning are compatible with a priorism and empiricism, and with the view that all, or only a few, are “rational.”

²⁰ On Liberty, chap. 2. Freedom of speech may be valued on other grounds than its conduciveness to knowledge. It may be valued by epistemological pessimists, as mentioned in section 11, above.