It is obvious that the coherency and force of the above passage depends on the idea, that there is a real power in the strongest inclination or desire of the mind, which renders it difficult to be surmounted or overcome. For if we suppose, that our inclinations or desires are merely the occasions on which we act, and that they themselves exert no influence or efficiency in the production of our volitions, it would be absurd to speak of the difficulty of overcoming them, as well as to speak of this difficulty as increasing with the increasing strength of the inclination, or desire. Take away this idea, show that there is no real strength in motives, or desires and inclinations, and the above extract will lose all its force; it will fall to pieces of itself. Indeed, the idea or supposition in question, is one of the strongholds of the necessitarian. External objects are regarded as the efficient causes of desire; desire as the efficient cause of volition; and in this way, the whole question seems to be settled. The same result would follow, if we should suppose that desire is awakened not exclusively by external objects, but partly by that which is external, and partly by that which is internal. On this supposition, as well as on the former, the will would seem to be under the dominion of the strongest desire or inclination of the soul. The assumption, that there is a real efficiency exerted by the desires and inclinations of the soul, has been, so far as I know, universally conceded to the necessitarian. He seems to have been left in the undisputed possession of this stronghold; and yet, upon mature reflection, I think we may find some reason to call it in question. If I am not greatly mistaken, we may see that the necessitarian has some reason to abate the loftiness of his tone, when he asserts, that "we _know_ that the feelings do exert an influence in the production of volition." This may appear very evident to his mind; nay, at first view, it may appear very evident to all minds; and yet, after all, it may be only an "idol of the tribe." It is a commonly received opinion, among philosophers, that the passions, desires, &c., do really exert an influence to produce volition. This was evidently the idea of Burlamaqui. He draws a distinction between voluntary actions and free actions; and as an instance of a voluntary action which is not free, he cites the case of a man who, as he supposes, is constrained to act from fear. He supposes that such an action, though voluntary, is not free, because it is brought about by the irresistible influence of the passion of fear.