Michael Chiariello

Agassi describes himself as "the foremost exponent and leading critic" of his teacher, Sir Karl Popper, who, he claims, is "the greatest philosopher of the mid-century". This account of his studies under Popper applies the idea that criticism is an expression of respect, so forcefully preached by Popper, and notes Popper's tragic failure both as a teacher and as a leader; and we learn here of Popper's failure to practice his own teachings, of Agassi's loss due to a repeated failure to communicate, and the public's loss of Popper's intellectual leadership. Agassi does not hold much back, and even reports the charges of treason voiced by insiders provoked by the circulation of earlier drafts of this work.

The context of Popper’s advocacy of critical rationalism is his defense of the open society. Popper rejects uncritical or comprehensive rationalism as self-defeating and thus an invitation to irrationalism which, in turn, endangers the open society. Bartley argued that a thoroughly critical rationalism can remain comprehensive and consistent, rendering unnecessary Popper’s “minimal concession to irrationalism.” Popper’s rejection of Bartley’s claim and the ensuing debate are abstracted from the metapolitical question of the best defense of a rationalism supportive of an open society. This essay surveys the debate over the limits of critical rationalism in terms of Popper’s original political, or metapolitical project.