the two, and there could be no reason for saying that the knowledge of "causes," as distinguished from "laws," is wholly inaccessible to the human faculties. There is thus a real and important distinction between "laws" considered simply as general facts, and "causes" considered as efficient agents; and the two cannot be reduced to the same category, otherwise than by giving such an extension to the term "law" as shall make it comprehensive of _causation_; and even then, the distinction remains between the mere formulas of Science and the actual forces of Nature. "The laws of Nature," says the sagacious Dr. Reid, "are the _rules_ according to which the effects are produced, but there must be a _cause_ which operates according to these rules. The rules of navigation never navigated a ship; the rules of architecture never built a house."[190] It might be shown, were it needful for our present purpose, that the object of Science is _threefold: first_, to ascertain particular facts; _secondly_, to reduce these facts under general laws; and, _thirdly_, to investigate the "causes" by which both _facts_ and _laws_ may be accounted for. The exclusion of any one of the three would be fatal to Philosophy as well as Religion; and it is prohibited by the "natural laws" of the human mind, which has the capacity not only of observing particular facts, but of comparing and contrasting them so as to deduce from them a knowledge of general laws, and which is also imbued with an instinctive and spontaneous tendency to ascribe every change that is observed to some "power" or "cause" capable of producing such an effect. It might further be shown, that in every instance a "cause," properly so called, is a _substance_ or _being_ possessing certain properties or powers,--properties which may be called, if you will, the "laws" of that substance, but which necessarily include the idea of _causation_ or _efficiency_; that in the case of mere physical agency, there must be a plurality of substances so related as that the one shall act on the other in certain conditions which are indispensable to their mutual action; and that these requirements leave ample room for those manifold adjustments and adaptations on which the argument from "design," in favor of the Perfections and Providence of God, is founded. The mere recognition of "general laws," considered simply as the "cooerdination of facts," and especially as exclusive of the idea of causation or efficiency, can never satisfy the demands of reason, nor exhaust the legitimate functions of Science. For, in the expressive words of Sir John Herschell, "It is high time that philosophers, both physical and others, should come to some nearer agreement than seems to prevail, as to the meaning they intend to convey in speaking of causes and causation. On the one hand, we are told that the grand object of physical inquiry is to explain the nature of phenomena by referring them