Yet this is what M. Bergson does in his whole defence of metaphysical vitalism, and especially in the instance of the evolution of eyes by two different methods, which is his palmary argument.  Since in some molluscs and in vertebrates organs that coincide in being organs of vision are reached by distinct paths, it cannot have been the propulsion of mechanism in each case, he says, that guided the developments, which, being divergent, would never have led to coincident results, but the double development must have been guided by a common tendency towards vision.  Suppose (what some young man in a laboratory may by this time have shown to be false) that M. Bergson’s observations have sounded the facts to the bottom; it would then be of the ultimate nature of things that, given light and the other conditions, the two methods of development will end in eyes; just as, for a peasant, it is of the ultimate nature of things that puddles can be formed in two quite opposite ways, by rain falling from heaven and by springs issuing from the earth; but as the peasant would not have reached a profound insight into nature if he had proclaimed the presence in her of a tendency to puddles, to be formed in inexplicably different ways; so the philosopher attains to no profound insight when he proclaims in her a tendency to vision. If those words express more than ignorance, they express the love of it.  Even if the vitalists were right in despairing of further scientific discoveries, they would be wrong in offering their verbiage as a substitute.  Nature may possibly have only a very loose hazy constitution, to be watched and understood as sailors watch and understand the weather; but Neptune and AEolus are not thereby proved to be the authors of storms.  Yet M. Bergson thinks if life could only be safely shown to arise unaccountably, that would prove the invisible efficacy of a mighty tendency to life.  But would the ultimate contexture and miracle of things be made less arbitrary, and less a matter of brute fact, by the presence behind them of an actual and arbitrary effort that such should be their nature?  If this word “effort” is not a mere figure of rhetoric, a name for a movement in things of which the end happens to interest us more than the beginning, if it is meant to be an effort actually and consciously existing, then we must proceed to ask:  Why did this effort exist?  Why did it choose that particular end to strive for?  How did it reach the conception of that end, which had never been realised before, and which no existent nature demanded for its fulfilment?  How did the effort, once made specific, select the particular matter it was to transform?  Why did this matter respond to the disembodied effort that it should change its habits?  Not one of these questions is easier to answer than the question why nature is living or animals have eyes.  Yet without seeking to solve the only real problem, namely, how nature is actually constituted, this introduction