In this article, I discuss the relationship between Karl Popper’s conception of critical rationalism and William Bartley’s conception of pancritical rationalism. Both Popper and Bartley tended to identify rationality with openness to criticism, but they are usually considered to be disagreeing about whether rationality is limited or comprehensive and whether or not it applies to moral attitudes. These traditional interpretations are found wanting, and I make the case that there is—and was—no genuine, substantial conflict between Popper’s critical and Bartley’s pancritical (...) rationalism. The apparent disagreement between Popper and Bartley about critical versus pancritical rationalism is nothing but a tangle of several factors, including the misconstrual of Popper’s critical rationalism by Bartley, Popper’s disagreement with Bartley’s criticism of critical rationalism, Popper’s disagreement with Bartley’s claim that his formulation is superior to Popper’s formulation of critical rationalism in The Open Society and Its Enemies, and the clash of Bartley’s ambitions with Popper’s rather cold attitude toward his cherished ideas. New (so far unpublished and not discussed) archival material—Popper’s interview and two letters to Leslie Graves dated 1992—is invoked to provide crucial evidence for this interpretation. (shrink)

This paper deals with Popper's little-known work on deductive logic, published between 1947 and 1949. According to his theory of deductive inference, the meaning of logical signs is determined by certain rules derived from ?inferential definitions? of those signs. Although strong arguments have been presented against Popper's claims (e.g. by Curry, Kleene, Lejewski and McKinsey), his theory can be reconstructed when it is viewed primarily as an attempt to demarcate logical from non-logical constants rather than as a semantic foundation for (...) logic. A criterion of logicality is obtained which is based on conjunction, implication and universal quantification as fundamental logical operations. (shrink)

Popper’s theory of learning is sometimes met with incredulity because Popper claims that there is no transference of knowledge or knowledge elements from outside the individual, neither from the physical environment nor from others. Instead, he claims that we can improve our present theories by discovering their inadequacies.The intent of this article is not to persuade educators to adopt Popper’s approach uncritically to build their professional knowledge. Rather, it presents a discussion on the need for teachers to adopt a critical (...) approach in eliminating what is inadequate and preserve what is adequate by modifying or abandoning whatever traditions or practices that are inadequate to improve their teaching practice. Popper claims that knowledge advances by searching for and eliminating error contained in our theory. In other words, we can improve our present theories by finding out their inadequacies. (shrink)

Currently, testimony is studied extensively in Anglo-American philosophy. However, most of this work is done from a justificationist perspective in which philosophers try to justify our reliance on testimony in some way. I agree with Popper that justificationism is radically mistaken. Thus, I construct an account of how we respond to testimony that in no way attempts to justify our reliance on it. This account is not a straightforward exegesis of Popper, as he never tackled testimony systematically. It makes use, (...) however, of several of Popper's key insights and incorporates them into a viable theory of testimony. Key Words: testimony • anti-justificationism • social epistemology • situational analysis • defeasibility. (shrink)

Bartley’s pancritical rationalism is seen by some as being a refinement of Popper’s critical rationalism. I contest this view and argue that pancritical rationalism is obtained from critical rationalism by removing some of its most important and useful features. The remainder consists of a restatement of some of Popper’s key ideas and an interpretation of others that I attempt to show is not entirely faithful to what Popper says.

From the time of its birth, Popper’s theory of falsifiability has been fiercely criticized from various viewpoints. In the author’s view, however, those various criticisms all have the same root in their assumption that a falsification must be certain and conclusive. As the theory of falsifiability has never had such an assumption, it is the source of misunderstanding. By discarding it, we can reply to every criticism and thereby clarify the role of falsifiability in our search for better knowledge; that (...) is, it makes our attitude open to a yet unknown world. Key Words: Popper • falsifiability • openness • inconclusive falsification • second Popper legend. (shrink)

From the time of its birth, Popper 's theory of falsifiability has been fiercely criticized from various viewpoints. In the author's view, however, those various criticisms all have the same root in their assumption that a falsification must be certain and conclusive. As the theory of falsifiability has never had such an assumption, it is the source of misunderstanding. By discarding it, we can reply to every criticism and thereby clarify the role of falsifiability in our search for better knowledge; (...) that is, it makes our attitude open to a yet unknown world. (shrink)