Some ingenious thinkers, on both sides of the question, have not been fully satisfied with this method of stating the grounds of our opinion. It has been said by our opponents, that if we found merely on the acknowledged difference between two sets of properties or phenomena, while we admit that the substance or substratum is in itself entirely unknown to us, or known only through the medium of the properties to which we refer,--then the dispute becomes a purely _verbal_ one, and can amount to nothing more than this, whether a _substance_ of whose essence we are entirely ignorant should be called by the name of "matter" or by the name of "spirit." But the dispute is not a purely _verbal_ one, even on the suppositions which have been stated. For it is essential to a right "philosophy of nature," that every substance possessing peculiar properties should have a distinctive name. Thus, even in the material world itself, we distinguish sulphur from soda, gold from granite, and magnesia from electricity or _odyle_. Why? Because, while they have some properties in common, in virtue of which we rank them in the same category as "material substances," they have, severally, certain distinctive or peculiar characteristics, which forbid us to call the one by the same name as the other. And for precisely the same reason, when we find another class of properties and powers existing in certain beings, which are totally different from those belonging to mere material substances,--incapable not only of being identified with them, but also of being accounted for by means of them,--we are equally warranted in ascribing these properties to a _substance_, and in affirming that this substance, of which we know nothing except through its properties, is radically different from "matter." That there is something more than a mere _verbal_ difference between us and our opponents might seem to be admitted by themselves, when they evince so much zeal in assailing our position and defending their own; but it becomes strikingly apparent as soon as we extend our inquiry so as to embrace the grand question respecting the distinction, if any, between God and the material universe.