Thus, upon the whole, if we identify the principle of causation with the principle of mind--as we are bound to do by the theory of Monism--we thereby draw a great and fundamental distinction between causation as this occurs in the external world, and as it occurs within the limits of our own subjectivity. And the distinction consists in the unconditional nature of a causal sequence in the external world, as against the conditional nature of it in the other case; the condition to the effective operation of a motive--as distinguished from a motor--is the acquiescence of the first cause upon which that motive is operating. To the foregoing argument it may be objected that by expressly regarding the human mind as a first cause of its own volitions, I imply that that mind can itself have had no cause, which appears to be self-evidently absurd. But here again the absurdity only arises from our inveterate habit of regarding the principle of causation as logically prior to that of mind. If we expressly refuse to do this, there is nothing absurd in supposing the principle of mind wherever it occurs, as itself uncaused. For if, as we are now supposing, this principle is identical with that of causation, to say that any mind is caused would be to say that a cause is the cause of itself, which would be really absurd. Under the present point of view, therefore, it would be a meaningless question to ask for the cause of a human mind, since, _ex hypothesi_, a human mind is a part of the self-existing substance, although not on this account self-existing as to its individual personality. As argued in a previous chapter, the personality appears to arise on account of circumscription, or the isolation of a constituent part of the World-eject. Therefore, although it may be reasonable to ask for a cause of this circumscription--or of the personality--it is not reasonable to ask for a cause of the substance which is thus circumscribed, or of the quality of spontaneity which that substance exhibits.