Page:Treatise of Human Nature (1888).djvu/268

248 of the ideas, you conclude that 'tis impossible motion can ever produce thought, or a different position of parts give rise to a different passion or reflection. Nay 'tis not only possible we may have such an experience, but 'tis certain we have it; since every one may perceive, that the different dispositions of his body change his thoughts and sentiments. And shou'd it be said, that this depends on the union of soul and body; I wou'd answer, that we must separate the question concerning the substance of the mind from that concerning the cause of its thought; and that confining ourselves to the latter question we find by the comparing their ideas, that thought and motion are different from each other, and by experience, that they are constantly united; which being all the circumstances, that enter into the idea of cause and effect, when apply'd to the operations of matter, we may certainly conclude, that motion may be, and actually is, the cause of thought and perception.

There seems only this dilemma left us in the present case; either to assert, that nothing can be the cause of another, but where the mind can perceive the connexion in its idea of the objects: Or to maintain, that all objects, which we find constantly conjoin'd, are upon that account to be regarded as causes and effects. If we choose the first part of the dilemma, these are the consequences. First, We in reality affirm, that there is no such thing in the universe as a cause or productive principle, not even the deity himself; since our idea of that supreme Being is deriv'd from particular impressions, none of which contain any efficacy, nor seem to have any connexion with any other existence. As to what may be said, that the connexion betwixt the idea of an infinitely powerful being, and that of any effect, which he wills, is necessary and unavoidable; I answer, that we have no idea of a being endow'd with any power, much less of one endow'd with infinite power. But if we will change expressions, we can only define power by connexion; and then in saying, that the idea of an