But, to complete this explanation, it is necessary to add that, in the production of their natural effects, creatures are more than instrumental. The primary cause, God, and the secondary causes, creatures, are both _principal_ causes of natural effects; though the latter are subordinate to the influence of the former. Both God and the creature are total causes; that is, the effect entirely depends on the secondary, as it entirely depends on the primary cause, though in a different manner; for the influx of the primary cause is general, while that of the secondary cause is particular. Hence these two causes bear to the effect produced by them the same relation as two premises bear to their conclusion. God’s influence is to the effect produced what a general principle or a major proposition is to the conclusion; whilst the creature’s influence is to the same effect what a minor proposition or the application of the general principle is to the conclusion. Take, for instance, the general truth, “Virtue is a rational good,” as a major proposition. This general truth may be applied in different manners, and lead to different conclusions, good or bad, according as the application is right or wrong. If you subsume, “Temperance is a virtue,” you will immediately obtain the good conclusion that “Temperance is a rational good.” But, if you subsume, “Pride is a virtue,” you will reach the monstrous conclusion that “Pride is a rational good.” Now, this conclusion, however monstrous, could not be drawn without the general principle; and yet its monstrosity does not arise from the general principle, but only from its wrong application. Thus the general principle remains good and true in spite of the bad and false conclusion. And in the same manner the influence of the first cause on natural effects remains good and perfect, though the effects themselves, owing to the influence of the secondary causes, are imperfect and monstrous. You now understand, I hope, how the exceptional production of monstrosities can be reconciled with the idea of a conscious power acting with design. XIII. Brain And Soul. _Reader._ And now, doctor, please tell me what is your doctrine on the human soul. _Büchner._ The human soul is “a product of matter” (p. 132)—“a product of the development of the brain” (p. 197). _Reader._ Indeed? _Büchner._ “The brain is the seat and organ of thought; its size, shape, and structure are in exact proportion to the magnitude and power of its intellectual functions” (p. 107). _Reader._ What do you mean by _thought_? _Büchner._ Need I explain a term so universally known?