This, in its simplest form, is the so-called argument of modern materialism.  Argument, however, it is quite plain it is not.  It is a mere dogmatic statement, that can give no logical account of itself, and must trust, for its acceptance, to the world’s vague sense of its fitness.  The modern world, it is true, has mistaken it for an argument, and has been cowed by it accordingly; but the mistake is a simple one, and can be readily accounted for.  The dogmatism of denial was formerly a sort of crude rebellion, inconsistent with itself, and vulnerable in a thousand places.  Nature, as then known, was, to all who could weigh the wonder of it, a thing inexplicable without some supernatural agency.  Indeed, marks of such an agency seemed to meet men everywhere.  But now all this has changed.  Step by step science has been unravelling the tangle, and has loosened with its human fingers the knots that once seemed deo digni vindice.  It has enabled us to see in nature a complete machine, needing no aid from without.  It has made a conception of things rational and coherent that was formerly absurd and arbitrary.  Science has done all this; but this is all that it has done.  The dogmatism of denial it has left as it found it, an unverified and unverifiable assertion.  It has simply made this dogmatism consistent with itself.  But in doing this, as men will soon come to see, it has done a great deal more than its chief masters bargained for.  Nature, as explained by science, is nothing more than a vast automaton; and man with all his ways and works is simply a part of Nature, and can, by no device of thought, be detached from or set above it.  He is as absolutely automatic as a tree is, or as a flower is; and is an incapable as a tree or flower of any spiritual responsibility or significance.  Here we see the real limits of science.  It will explain the facts of life to us, it is true, but it will not explain the value that hitherto we have attached to them.  Is that solemn value a fact or fancy?  As far as proof and reason go, we can answer either way.  We have two simple and opposite statements set against each other, between which argument will give us no help in choosing, and between which the only arbiter is a judgment formed upon utterly alien grounds.  As for proof, the nature of the case does not admit of it.  The world of moral facts, if it existed a thousand times, could give no more proof of its existence than it does now.  If on other grounds we believe that it does exist, then signs, if not proofs of it, at once surround us everywhere.  But let the belief in its reality fail us, and instantly the whole cloud of witnesses vanishes.  For science to demand a proof that shall convince it on its own premisses is to demand an impossibility, and to involve a contradiction in terms.  Science is only possible on the assumption that nature is uniform.  Morality is only possible on the assumption that this uniformity is interfered with by the will.  The world of morals is as distinct from the world of science as a wine is from the cup that holds it; and to say that it does not exist because science can find no trace of it, is to say that a bird has not flown over a desert because it has left no footprints in the sand.  And as with morals, so it is with religion.  Science will allow us to deny or to affirm both.  Reason will not allow us to deny or affirm only one.