Yet it is plain, and I shall take it for granted here, that when I assent to a proposition, I ought to have some more legitimate reason for doing so, than the brilliancy of the image of which that proposition is the expression. That I have no experience of a thing happening except in one way, is a cause of the intensity of my assent, if I assent, but not the reason of my assenting. In saying this, I am not disposed to deny the presence in some men of an idiosyncratic sagacity, which really and rightly sees reasons in impressions which common men cannot see, and is secured from the peril of confusing truth with make-belief; but this is genius, and beyond rule. I grant too, of course, that accidentally impressiveness does in matter of fact, as in the instance which I have been giving, constitute the motive principle of belief; for the mind is ever exposed to the danger of being carried away by the liveliness of its conceptions, to the sacrifice of good sense and conscientious caution, and the greater and the more rare are its gifts, the greater is the risk of swerving from the line of reason and duty; but here I am not speaking of transgressions of rule any more than of exceptions to it, but of the normal constitution of our minds, and of the natural and rightful effect of acts of the imagination upon us, and this is, not to create assent, but to intensify it. 2. Next, Assent, however strong, and accorded to images however vivid, is not therefore necessarily practical. Strictly speaking, it is not imagination that causes action; but hope and fear, likes and dislikes, appetite, passion, affection, the stirrings of selfishness and self-love. What imagination does for us is to find a means of stimulating those motive powers; and it does so by providing a supply of objects strong enough to stimulate them. The thought of honour, glory, duty, self-aggrandisement, gain, or on the other hand of Divine Goodness, future reward, eternal life, perseveringly dwelt upon, leads us along a course of action corresponding to itself, but only in case there be that in our minds which is congenial to it. However, when there is that preparation of mind, the thought does lead to the act. Hence it is that the fact of a proposition being accepted with a real assent is accidentally an earnest of that proposition being carried out in conduct, and the imagination may be said in some sense to be of a practical nature, inasmuch as it leads to practice indirectly by the action of its object upon the affections.