The Western tradition has tended to identify thinking with the purely logical, excluding other kinds of thinking (such as thinking by analogy, correlation, imaginative simulation) from philosophy, without denying their indispensability in the conduct of life. The central argument of Unreason Within Reason is that it is this endeavour to detach the logical from other kinds of thinking which has led to the present crisis of rationality, in which reason seems everywhere to be undermining its own foundations. The concepts from which logical thinking starts are inescapably rooted in the spontaneous correlation of the similar/contrasting and contiguous/remote which, according to Jakobsonian linguistics, structures the sentences analysed by logic. Logical thinking can turn back on itself to criticise the correlations, but cannot detach itself to replace them by logically impregnable foundations. The still-viable type of rationalism is a variant on Popper's critical rationalism which does not, like Popper's, relegate the non-logical element in thought to the psychology of knowledge. No mode of thinking - poetic, mythic, mystical - is inherently irrational; the function of the logical is not to replace them but to test them. Graham finds this approach relevant to the fact/value and egoism/altruism problems in moral philosophy and to the epistemological problem of conflicting conceptual schemes, as well as to situating myth and mysticism in relation to philosophy and to the development of a variety of perspectivism clearly distinguishable from relativism. Special attention is paid to Nietzsche and Bataille, as representative critics of rationalism, and to Chinese philosophy, as a tradition which has not isolated the logical from other kinds of thinking.