When I speak of reason or rationalism, all I mean is the conviction that we can learn through criticism of our mistakes and errors, especially through criticism by others, and eventually also through self-criticism. A rationalist is simply someone for whom it is more important to learn than to be proved right; someone who is willing to learn from others – not by simply taking over another’s opinions, but by gladly allowing others to criticize his ideas and by gladly criticizing the ideas of others. The emphasis here is on the idea of criticism or, to be more precise, critical discussion. The genuine rationalist does not think that he or anyone else is in possession of the truth; nor does he think that mere criticism as such helps us achieve new ideas. But he does think that, in the sphere of ideas, only critical discussion can help us sort the wheat from the chaff. He is well aware that acceptance or rejection of an idea is never a purely rational matter; but he thinks that only critical discussion can give us the maturity to see an idea from more and more sides and to make a correct judgement of it.
This assessment of critical discussion also has its human side. For the rationalist knows perfectly well that critical discussion is not the only relationship between people: that, on the contrary, rational critical discussion is a rare phenomenon in our lives. Yet he thinks that the ‘give and take’ attitude fundamental to critical discussion is of the greatest purely human significance. For the rationalist knows that he owes his reason to other people. He knows that the rational critical attitude can only be the result of others’ criticism, and that only through others’ criticism can one arrive at self-