Accordingly all its technical terms in some subtle way presuppose a misunderstanding of my thesis.

It is perhaps as well to state explicitly that if the reader indulges in the facile vice of bifurcation not a word of what I have here written will be intelligible.
The last two chapters do not properly belong to the special course.
Chapter VIII is a lecture delivered in the spring of 1920 before the Chemical Society of the students of the Imperial College of Science and Technology.

It has been appended here as conveniently summing up and applying the doctrine of the book for an audience with one definite type of outlook.
This volume on 'the Concept of Nature' forms a companion book to my previous work _An Enquiry concerning the Principles of Natural Knowledge_.

Either book can be read independently, but they supplement each other.

In part the present book supplies points of view which were omitted from its predecessor; in part it traverses the same ground with an alternative exposition.