As has been said, the Monistic philosophy claims to be above all things scientific, and upon this ground are we bidden to accept it. But what is the meaning of this claim? The one argument, apart from mere assertion, brought to show that spirit is not distinct from matter, is drawn from the part undoubtedly played by the brain in the process of thought, though we see far less in this, as in other connexions, than the assertions made by unscientific writers might lead us to imagine. But when all this is most fully acknowledged can it be said that the state of the question is changed from what it was? To listen to Monists, it might be supposed that the intimate connexion between soul and body is a new discovery, undreamt of in former ages,--and that we have now arrived at a demonstration that it is our material part that actually does our thinking. But, as a matter of fact, like other fundamental questions, this is exactly as it has ever been, and so far as Science is concerned, we are just as much in the dark respecting it as men ever were. Though the philosophers of former days were unaware of all the departmental details of brain activity, they understood as well as we do the essential point, that in our composite nature soul and body form _one_ being, whose every operation is of mixed character like itself. The soul alone is the intelligent principle, yet all objects of knowledge must come to it through sense, and in the senses it can be reached only by the mechanical media of light, or sound, or touch. So firm was their grip of this principle that the Schoolmen styled the soul the "substantial form" of the body, and in their mouth this term expressed a union more essential and intimate than modern philosophers can perhaps imagine. And, on the other hand, have all the results of modern research brought anything to light which tends to show that matter can by any possibility _think_? We are assured on the contrary, upon unimpeachable authority, that however we may succeed in tracing the mechanical processes of sensation to their furthest limit, it remains absolutely inconceivable to us how the gulf is crossed that lies between this and rational perception. So Professor Tyndall tells us:[172]