Bergson’s The Two Sources of Morality and Religion was published in 1932, and is one of the major French philosophical works of this century. In it the main dichotomy of existentialist ethics is foreshadowed. Following the earlier French philosophers Maine de Biran and Ravaisson in his preoccupation with habit, he shows the affinity between habit and everyday morality, and begins with what is, in effect, an account of what has more recently been referred to in French as the ‘quotidien’ (the everyday). Generally speaking, throughout his work, Bergson identifies habit with reason, which, in the context of my subject, I want to narrow down to ‘closed’ or ‘constituted’ reason, because this is really the only kind of reason which Bergson recognises. He does not feel any need to draw the distinction between closed and open rationalism that he draws between closed and open morality and religion. I should, indeed, be inclined to assert that recent French rationalistic philosophy has developed a distinction suggested, but left unexplored, by Bergson, whereas much post-war existentialist philosophy (in which ethical considerations are latent) has done no more than elaborate the dualism put forward in The Two Sources.