of thought in most intimate union with a certain particle of extended matter? But he had so distinct a conception of mind being distinct from body, that he could not assign any particular cause of the union between the two, or of the mind itself, but was obliged to have recourse to the cause of the whole universe, that is to God. Further, I should much like to know, what degree of motion the mind can impart to this pineal gland, and with what force can it hold it suspended? For I am in ignorance, whether this gland can be agitated more slowly or more quickly by the mind than by the animal spirits, and whether the motions of the passions, which we have closely united with firm decisions, cannot be again disjoined therefrom by physical causes; in which case it would follow that, although the mind firmly intended to face a given danger, and had united to this decision the motions of boldness, yet at the sight of the danger the gland might become suspended in a way, which would preclude the mind thinking of anything except running away. In truth, as there is no common standard of volition and motion, so is there no comparison possible between the powers of the mind and the power or strength of the body; consequently the strength of one cannot in any wise be determined by the strength of the other. We may also add, that there is no gland discoverable in the midst of the brain, so placed that it can thus easily be set in motion in so many ways, and also that all the nerves are not prolonged so far as the cavities of the brain. Lastly, I omit all the assertions which he makes concerning the will and its freedom, inasmuch as I have abundantly proved that his premisses are false. Therefore, since the power of the mind, as I have shown above, is defined by the understanding only, we shall determine solely by the knowledge of the mind the remedies against the emotions, which I believe all have had experience of, but do not accurately observe or distinctly see, and from the same basis we shall deduce all those conclusions, which have regard to the mind's blessedness. AXIOMS. I. If two contrary actions be started in the same subject, a change must necessarily take place, either in both, or in one of the two, and continue until they cease to be contrary. II. The power of an effect is defined by the power of its cause, in so far as its essence is explained or defined by the essence of its cause. (This axiom is evident from III.vii.) PROPOSITIONS. Prop.I. Even as thoughts and the ideas of things are arranged and associated in the mind, so are the modifications of body or the images of things precisely in the same way arranged and associated in the body.