PART IV:

no conclusions which do not follow from self—evident premisses, and would affirm nothing which he did not clearly and distinctly perceive, and who had so often taken to task the scholastics for wishing to explain obscurities through occult qualities, could maintain a hypothesis, beside which occult qualities are commonplace. What does he understand, I ask, by the union of the mind and the body? What clear and distinct conception has he got of thought in most intimate union with a certain particle of extended matter? Truly I should like him to explain this union through its proximate cause. 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