This book is concerned with the problem of how men actually think. The aim of these studies is to investigate not how thinking appears in textbooks on logic, but how it really functions in public life and in politics as an instrument of collective action. Philosophers have too long concerned themselves with their own thinking. When they wrote of thought, they had in mind primarily their own history, the history of philosophy, or quite special fields of knowledge such as mathematics or physics. This type of thinking is applicable only under quite special circumstances, and what can be learned by analysing it is not directly transferable to other spheres of life. Even when it is applicable, it refers only to a specific dimension of existence which does not suffice for living human beings who are seeking to comprehend and to mould their world. Meanwhile, acting men have, for better or for worse, proceeded to develop a variety of methods for the experiential and intellectual penetration of the world in which they live, which have never been analysed with the same precision as the so-called exact modes of knowing. When, however, any human activity continues over a long period without being subjected to intellectual control or criticism, it tends to get out of hand.