The expositor of Hume, who wishes to do his work thoroughly, as far as it goes, cannot but fall into perplexity[30] when he contrasts this language with that of the sections of the third part of the _Treatise_, entitled, _Why a Cause is Always Necessary_, and _Of the Idea of Necessary Connexion_. It is there shown, at large, that "every demonstration which has been produced for the necessity of a cause is fallacious and sophistical" (I. p. 111); it is affirmed, that "there is no absolute nor metaphysical necessity that every beginning of existence should be attended with such an object" [as a cause] (I. p. 227); and it is roundly asserted, that it is "easy for us to conceive any object to be non-existent this moment and existent the next, without conjoining to it the distinct idea of a cause or productive principle" (I. p. 111). So far from the axiom, that whatever begins to exist must have a cause of existence, being "self-evident," as Philo calls it, Hume spends the greatest care in showing that it is nothing but the product of custom, or experience. And the doubt thus forced upon one, whether Philo ought to be taken as even, so far, Hume's mouth-piece, is increased when we reflect that we are dealing with an acute reasoner; and that there is no difficulty in drawing the deduction from Hume's own definition of a cause, that the very phrase, a "first cause," involves a contradiction in terms. He lays down that,-- "'Tis an established axiom both in natural and moral philosophy, that an object, which exists for any time in its full perfection without producing another, is not its sole cause; but is assisted by some other principle which pushes it from its state of inactivity, and makes it exert that energy, of which it was secretly possessed."--(I. p. 106.) Now the "first cause" is assumed to have existed from all eternity, up to the moment at which the universe came into existence. Hence it cannot be the sole cause of the universe; in fact, it was no cause at all until it was "assisted by some other principle"; consequently the so-called "first cause," so far as it produces the universe, is in reality an effect of that other principle. Moreover, though, in the person of Philo, Hume assumes the axiom "that whatever begins to exist must have a cause," which he denies in the _Treatise_, he must have seen, for a child may see, that the assumption is of no real service.