a1 University of Brussels
There is an argument, well known in the history of philosophy, which makes all knowledge ultimately depend on some kind of intuitive or sensory immediacy. According to this argument, either the proposition itself is self–evident;2 or else it can be shown to follow, with the help of a chain of intermediate links, from other propositions which are self–evident. Moreover, it is this self–evidence of immediate knowledge and only this which, again speaking traditionally, sufficiently guarantees the truth of the affirmations of a science as opposed to those of various and fluctuating opinions.
1 The first of two Special University Lectures delivered at University College in the University of London in March 1957. The lecture was translated from the French by Mrs. R. B. Braithwaite. It has appeared in French in Dialectica (June 1957) and the Editor of PHILOSOPHY is grateful to the Editor of that Journal for permission to print this translation.