The subject of this pleasantry is, indeed, it must be owned, so absurd in itself, as scarcely to require the aid of wit, to render it ridiculous; and yet this more than poetic personification of the mere figure of a body, as itself a separate unity, which appears to us too absurd almost to be feigned as an object of philosophic belief, even to such a mind as that of Crambé, was what, for age after age, seemed to the most intelligent philosophers a complete explanation of all the wonders of the universe; and _substantial forms_, far from needing a retreat among Gentlemen Ushers at Court, had their place of highest honours amid Doctors and Disputants, in every School and College, where, though they certainly could not give science, they at least served the temporary purpose of rendering the want of it unfelt, and of giving all the dignity which science itself could have bestowed. The vague and obscure notions, at present attached to the words power, cause, effect, appear to me very analogous to the notions of the Peripatetics, and, indeed, of the greater number of the ancient philosophers, with respect to form; and, I trust that as we have now universally learned to consider _form_, as nothing in itself, but only as the relation of bodies co-existing immediately in space, so _power_ will at length be as universally considered as only the relation which substances bear to each other _in time_, according as their phenomena are immediately successive; the invariable antecedent being the cause, the invariable consequent the effect; and the antecedent and consequent being all that are present in any phenomenon. There are, in nature, only substances; and all the substances in nature, are every thing that truly exists in nature. There is, therefore, no additional _power_, separate, or different from the antecedent itself, more than there is _form_, separate or different from the figured mass, or any other quality, without a substance. In the beautiful experiment of the prismatic decomposition of light, for example, the refracting power of the prism is not any thing separate or separable from it, more than its weight or transparency of colour. There are not a prism and transparency, but there is a prism giving passage to light. In like manner, there are not a prism, and refracting power, and coloured rays, but there are a prism and rays of various colours, which we have perceived to be deflected variously from their original line of direction, when they approach and quit the lens, and which we believe, will, in the same circumstances, continually exhibit the same tendency.