It was from overlooking the distinction here made, that Hume, Kant, and other metaphysicians were led to deny all knowledge of causation even in the action of mind. They confounded sufficiency with efficiency, and supposed, because the power did not always accomplish the end proposed, that it did not tend towards it, or exert any effect upon it. As the sufficiency of the volition can only be known _a posteriori_, or after experience, they imagined that there could be no cause but that which is infinite, or one which is invariably followed by the whole effect contemplated. They overlooked the fact, that, in the consciousness of _effort_,--as in the attempt to control the action of mind, to command the attention, &c.,--we have direct and full evidence of _power in action_, which is necessarily causal in its nature. The mental _nisus_ is true force, exerted with a foreknowledge of the effect to be produced, and necessarily followed by a result,--a partial one it may be,--but one which is a true effect, whether it answers the whole intention, or not. Here, then, we discern that necessary connection between two events, that absolute efficient agency, which was vainly sought in the world of matter. If these considerations are well founded, the whole framework of what are called "secondary causes" falls to pieces. The laws of nature are only a figure of speech; the powers and active inherent properties of material atoms are mere fictions. Mind alone is active; matter is wholly passive and inert. There is no such thing as what we usually call the course of nature; it is nothing but the will of God producing certain effects in a constant and uniform manner; which mode of action, however, being perfectly arbitrary, is as easy to be altered at any time as to be preserved. All events, all changes, in the external world, from the least even unto the greatest, are attributable to his will and power, which, being infinite, is always and necessarily adequate to the end proposed. The laws of motion, gravitation, affinity, and the like, are only expressions of the regularity and continuity of one infinite cause. The order of nature is the effect of divine wisdom, its stability is the result of divine beneficence. "Estne Dei sedes nisi terra, et pontus, et aer, Et coelum, et virtus? Superos quid quaerimus ultra? Jupiter est quodcunque vides, quocunque moveris."