When we can no longer interpret a phenomenon by the known, we must needs try to do so by the unknown...."

"It is well, in spite of everything, to seek an explanation of the inexplicable; it is by attacking it on every side at all hazards that we cherish the hope of overcoming it."

Maeterlinck. "The Unknown Guest."

CONTENTS

CHAPTERPAGE
I.[The meaning of Four-Dimensional Space][1]
II.[The scope of application and probable importance of the higher space concepts][21]
III.[Application to certain of the facts elicited by Psychic Research][39]
IV.[Some other possible applications of the hypothesis][92]
V.[Vitality and Will][113]
VI.[Higher Space and Physical Science][122]
VII.[The Connecting Link][136]
VIII.[The Religious Aspects of the hypothesis][168]
IX.[Summary and Conclusion][181]
[Appendix][187]
[Index][196]

PREFACE

The highly speculative and extrapolatory character of this book will be evident to all who are bold enough to read it.

I wish to make it perfectly clear that I have no intention of dogmatising on so obscure a subject. The suggestions which follow are purely tentative, and I am well aware that some of them are likely to prove mutually incompatible.