There is a popular misconception of Feyerabend's later philosophy according to which Feyerabend dropped rationality as the explanation of scientific advance, arguing that science's development is primarily guided by power, propaganda, and prejudice. Farrell exposes this error. He pinpoints Feyerabend's core insight that any complete set of methodological rules will necessarily be inconsistent. However, this does not make Feyerabend an irrationalist. Feyerabend's later philosophy can be reconstructed into a form of values-based rationalism: To be rational is to balance incompatible methodological demands.
Chapter 1 examines Feyerabend's reductio ad absurdum of ‘rationalist’ philosophies, identifying the main targets of Feyerabend's repeated attacks. A philosophy is ‘rationalist’ if it subscribes to one of the following three theses: the logical thesis, the factual-foundationalist thesis, or the methodological thesis. According to the logical thesis, logic is the model to which our thinking should conform, and that it provides the structure of our knowledge. According to the factual-foundationalist thesis, sources of factual knowledge exist whose truth is beyond doubt. According to the methodological thesis, to be a rational process, research must be conducted according to the rules of an unchanging scientific method. All three theses posit something universal, necessary and independent of the ongoing activity of acquiring knowledge. Feyerabend rejected all such conceptions of rationality, which relegate subjective elements and rhetorical moves to the realm of the irrational. By arguing that subjective elements and rhetorical moves play a positive role in scientific progress, Feyerabend was not arguing that science is irrational. Rather, he was attempting to expose the short-comings of ‘rationalist’ conceptions, of an otherwise rational process. He was arguing that given the actual historical development of the sciences, ‘rationalism’ should be rejected according to its own standards.
Chapter 2 argues that Feyerabend's anarchism should be understood in the context of his reductio ad absurdum of ‘rationalism’. Anything does not go. But if a methodology insists in having universal, atemporal rules of rationality, then there will be only one: Anything goes. The price of universality is a complete lack of content. The chapter also provides an exceptional analysis of Feyerabend's critique of Lakatos’ methodology of scientific research programmes, developing Feyerabend's reasons for calling Lakatos a ‘fellow anarchist’.
In Chapter 3, Farrell reconstructs Feyerabend's use of the notion of incommensurability and the pragmatic theory of observation. Farrell argues that Feyerabend's notion of incommensurability should best be understood in the context of his immanent criticisms of ‘rationalist’ models of theory comparison. Given such models, theories will be incommensurable, but if such models are dropped, then theories will be comparable in a number of ways.
Chapter 4 grapples with the difficult issues of Feyerabend's changing relationships to metaphysical realism and epistemological relativism. Farrell argues that although Feyerabend sometimes described himself as a Protagorean relativist, Feyerabend actually endorsed a form of minimal realism. He primarily bases his reconstruction of Feyerabend's metaphysical views on Feyerabend's late 1950s publications on quantum mechanism, and then attempts to show how they shed light on Feyerabend's later views.
Chapter 5 very briefly examines the longest-standing and most central aspects of Feyerabend's philosophy: proliferation and pluralism. Farrell reconstructs and defends Feyerabend's argument for pluralism based on the insight that theories can increase the empirical content of their rivals.
Chapter 6 discusses the nature and reasons for the transition in Feyerabend's philosophical development from his early Popperian theoretical pluralism to his later methodological pluralism, and then continues to untangle the issue of whether he was a relativist or a rationalist.
Chapter 7 develops Kuhn's values-based conception of rationality in order to explicate Feyerabend's views. The idea is that criteria of theory choice (such as accuracy, scope, explanatory power, simplicity, fruitfulness, and testability) do not function as rules that unequivocally determine choice, but instead as values that merely guide it.
Chapter 8 further develops and then justifies Farrell's interpretation of Feyerabend's later ideas as implicitly grounded on a values-based conception of rationality. Farrell argues that while Feyerabend insisted that there are no universal rules of rationality, he subscribed to the view that there are four universal, atemporal values of rationality: comprehensiveness, empirical accuracy, fruitfulness, and testability. However, these values are inherently irreconcilable: “The ultimate practical necessity of rationality is to attempt to balance the irreconcilable demands of the values of rationality, hence the title: Tightrope-Walking Rationality” (3).
In the final chapter, Farrell uses Dewey's ideas to characterize and defend Feyerabend's later philosophy as a form of nonreductive naturalism, according to which all aspects of existence are equally real, and no part is more fundamental than another. Atoms are not metaphysically more basic than consciousness; both are equally natural phenomena. This allows for the possibility of arguing ‘backward’, from ethical, social, or psychological convictions to the nature of reality. Decisions about how we understand the nature of reality should be made on the basis of whatever subjective, idiosyncratic form of life we desire.
Anyone interested in Feyerabend's later ideas should read this insightful book. It is the best reconstruction of Feyerabend's later views on rationality to date. There are, however, a number of serious problems (especially concerning the main theses of Chapters 3 and 4), not all of which can be examined here. I will limit myself to a single general remark. While Farrell's exceptional treatment of Feyerabend's notion of rationality admirably identifies and explicates Feyerabend's core insight (i.e., to be rational it is necessary to mediate between methodological demands that pull in different directions), in my view, Farrell drew a different lesson from it than did Feyerabend. Feyerabend did not attempt, or recommend, tightrope-walking rationality. He did not try to find some delicate balance between these divergent demands, either in the form of a single position or of a single metanarrative. Rather, he was a self-proclaimed philosophical pluralist, who alternately pushed conflicting ideas to their extremes, in order to expose their strengths and weaknesses. The lesson Feyerabend drew from his core insight was that we should alternatively jump off both sides of the rope: Rational enquirers should head in different directions, according to divergent methodological demands, instead of sticking dogmatically to a single point of view.
