My naturalism is sometimes taxed with being dogmatic, and if I were anxious to avoid that reproach, I might easily reduce my naturalism to a definition and say that if experience has any sources whatever, the sum and system of these sources shall be called nature. I know what speculative difficulties cluster about the notion of cause, which in one sense is quite unnecessary to science; but so long as time, process, and derivation are admitted at all, events may be traced back to earlier events which were their sources; and this universal flax of events will be called nature. Any existing persons, and any gods exercising power, will evidently be parts of nature. But I am not concerned to avoid dogmatism on such a point. Every assertion about existence is hazarded, it rests on animal faith, not on logical proof; and every argument to support naturalism, or to rebut it, implies naturalism. To deny that there are any facts (if scepticism can be carried so far) is still to dogmatize, no less than it would be to point to some fact in particular; in either case we descend into the arena of existence, which may betray our confidence. Any fact is an existence which discourse plays about and regards, but does not create. It is the essence of the practical intellect to prophesy about nature, and we must all do it As to the truth of our prophecy, that is always problematical, because nature is whatever nature happens to be; and as to our knowledge, starting as it does from a single point, the present position of the thinker, and falling away rapidly in dearness and certainty as the perspective recedes, it cannot pretend to draw the outlines of nature _a priori_: yet our knowledge of nature, in our neighbourhood and moral climate, is very considerable, since every known fact is a part of nature. It is quite idle to deny, for instance, that human life depends on cosmic and hygienic influences; or that in the end all human operations must run back somehow to the rotation of the earth, to the rays of the sun, to the moisture and fructification of the soil, to the ferment there of vegetative and dreaming spirits, quickened in animals endowed with locomotion into knowledge of surrounding things: whence the passionate imaginations which we find in ourselves. I know that things might have been arranged otherwise; and some of those alternative worlds may be minutely thought out in myth or in philosophy, in obedience to some dialectical or moral impulse of the human mind; but that all those other worlds are figments of fancy, interesting as poetry is interesting, and that only the natural world, the world of medicine and commerce, is actual, is obvious; so obvious to every man in his sane moments, that I have always thought it idle to argue the point. Argument is not persuasive to madmen; but they can be won over by gentler courses to a gradual docility to the truth. One of these gentler courses is this: to remember that madness is human,