The tu quoque argument is the argument that since in the end rationalism rests on an irrational choice of and commitment to rationality, rationalism is as irrational as any other commitment. Popper’s and Polanyi’s philosophies of science both accept the argument, and have on that account many similarities; yet Popper manages to remain a rationalist whereas Polanyi decided for an irrationalist version of rationalism. This is more marked in works of their respective followers, W. W. Bartley III and Thomas S. Kuhn. Bartley declares the rationalist’s very openness to criticism open to criticism, in the hope of rendering Popper’s critical rationalism quite comprehensive. Kuhn makes rationality depend on the existence of an accepted model for scientific research (paradigm), thus rendering Polanyi’s view of the authority of scientific leadership a sine qua non for scientific progress. The question raised here is, in what sense is a rationalist committed to his rationality, or an irrationalist to his specific axiom ? The tradition views only the life-long commitment as real. Viewing rationality as experimental open-mindedness, we may consider a rationalist unable to retreat into any life-long commitment — even commitment to science. In this way the logic of the tu quoque argument is made irrelevant: anyone able to face the choice between rationality and commitment is already beyond such a choice; it is one thing to be still naive and another — and paradoxical — thing to return to one’s naivete.