electricity, or chemical attraction, have any analogy to the power which manifests itself in growth and organization, is altogether a different question, and demands altogether a different chain of reasoning: if it be indeed a tree of knowledge, it will be known by its fruits, and these will depends not on the mere assertion, but on the inductions by which the position is supported, and by the additions which it makes to our insight into the nature of the facts it is meant to illustrate. To _account_ for Life is one thing; to explain Life another. In the first we are supposed to state something prior (if not in time, yet in the order of Nature) to the thing accounted for, as the ground or cause of that thing, or (which comprises the meaning and force of both words) as its _sufficient cause, quae et facit, et subest_. And to this, in the question of Life, I know no possible answer, but GOD. To account for a thing is to see into the principle of its possibility, and from that principle to evolve its being. Thus the mathematician demonstrates the truths of geometry by constructing them. It is an admirable remark of Joh. Bapt. a Vico, in a Tract published at Naples, 1710,(6) “Geometrica ideò demonstramus, quia facimus; physica si demonstrare possimus, faceremus. Metaphysici veri claritas eadem ac lucis, quam non nisi per opaca cognoscimus; nam non lucem sed lucidas res videmus. Physica sunt opaca, nempe formata et finita, in quibus Metaphysici veri lumen videmus.” The reasoner who assigns structure or organization as the antecedent of Life, who names the former a cause, and the _latter_ its effect, _he_ it is who pretends to account for life. Now Euclid would, with great right, demand of such a philosopher to _make_ Life; in the same sense, I mean, in which Euclid makes an Icosahedron, or a figure of twenty sides, namely, in the understanding or by an intellectual construction. An argument which, of itself, is sufficient to prove the untenable nature of Materialism.