"Newton demonstrated all the host of heaven to be but the elements of a vast mechanism, regulated by the same laws as those which express the falling of a stone to the ground. There is a passage in the preface to the first edition of the 'Principia' which shows that Newton was penetrated, as completely as Descartes, with the belief that all the phenomena of nature are expressible in terms of matter and motion:-- "'Would that the rest of the phenomena of nature could be deduced by a like kind of reasoning from mechanical principles. For many circumstances lead me to suspect that all these phenomena may depend upon certain forces, in virtue of which the particles of bodies, by causes not yet known, are either mutually impelled against one another, and cohere into regular figures, or repel and recede from one another; which forces being unknown, philosophers have as yet explored nature in vain. But I hope that, either by this method of philosophizing, or by some other and better, the principles here laid down may throw some light upon the matter.'" Here is a full-blown anticipation of an intelligible exposition of the Universe in terms of matter and force--the substantial basis of what smaller men call materialism and develop into what they consider to be a materialistic philosophy. But there is no necessity for any such scheme; and Professor Huxley himself, who is commonly spoken of by half-informed people as if he were a philosophic materialist, was really nothing of the kind; for although, like Newton, fully imbued with the mechanical doctrine, and of course far better informed concerning the biological departments of nature, and the discoveries which have in the last century been made,--and though he rightly regarded it as his mission to make the scientific point of view clear to his benighted contemporaries, and was full of enthusiasm for the facts on which materialists take their stand,--he saw clearly that these alone were insufficient for a philosophy. The following extracts from the Hume volume will show that he entirely repudiated materialism as a satisfactory or complete philosophical system, and that he was especially severe on gratuitous denials applied to provinces beyond our scope:-- "While it is the summit of human wisdom to learn the limit of our faculties, it may be wise to recollect that we have no more right to make denials, than to put forth affirmatives, about what lies beyond that limit. Whether either mind or matter has a 'substance' or not, is a problem which we are incompetent to discuss: and it is just as likely that the common notions upon the subject should be correct as any others.... 'The same principles which, at first view, lead to scepticism, pursued to a certain point, bring men back to common sense'" (p. 282).