1. The notion that because material energy is constant in quantity, therefore its transformations and transferences—which admittedly constitute terrestrial activity—are not susceptible of guidance or directive control. 2. The idea that the specific guiding power which we call "life" is one of the forms of material energy, so that directly it relinquishes its connection with matter other equivalent forms of energy must arise to replace it. The book is specially intended to act as an antidote to the speculative and destructive portions of Professor Haeckel's interesting and widely-read work, but in other respects it may be regarded less as a hostile attack than as a supplement—an extension of the more scientific portions of that work into higher and more fruitful regions of inquiry. OLIVER LODGE. University of Birmingham, _October 1905_. Contents CHAP. PAGE I MONISM 1 II "THE LAW OF SUBSTANCE" 14 III THE DEVELOPMENT OF LIFE 41 IV MEMORANDA FOR WOULD-BE MATERIALISTS 60 V RELIGION AND PHILOSOPHY 71 VI MIND AND MATTER 100 VII PROFESSOR HAECKEL'S CONJECTURAL PHILOSOPHY 125 VIII HYPOTHESIS AND ANALOGIES CONCERNING LIFE 136 IX WILL AND GUIDANCE 152 X FURTHER SPECULATION AS TO THE ORIGIN AND NATURE OF LIFE 179 LIFE AND MATTER CHAPTER I MONISM In his recent Presidential Address before the British Association, at Cambridge, Mr Balfour rather emphasised the existence and even the desirability of a barrier between Science and Philosophy which recent advances have tended to minimise though never to obliterate. He appeared to hint that it is best for scientific men not to attempt to philosophise, but to restrict themselves to their own domain; though, on the other hand, he did not appear to wish similarly to limit philosophers, by recommending that they should keep themselves unacquainted with scientific facts, and ignorant of the theories which weld those facts together. Indeed, in his own person he is an example of the opposite procedure, for he himself frequently takes pleasure in overlooking the boundary and making a wide survey of the position on its physical side—a thing which it is surely very desirable for a philosopher to do.