is the materialist doctrine of those forewarned folk, who have perceived the errors committed and endeavour to avoid them, while cherishing all that can be saved of the condemned doctrine. That which philosophers criticised in materialism was the misunderstanding of the principle of heterogeneity. The parallelists have seen this mistake, and have taken steps to respect this principle: we shall see in what way. They are especially prudent, and they excel in avoiding being compromised. They put forth their hypothesis as a provisional one, and they vaunt its convenience. It is, say they, a practical method of avoiding many difficulties; it becomes for philosophers an equivalent of that phrase which so many timorous ministers repeat: “Above all, no scrapes!”
Let us study the exact point on which parallelism has amended materialism. We have seen that every materialist doctrine is the expression of this idea, that physical phenomena are the only ones that are determined, measurable, explicable, and scientific. This idea does wonders in the natural sciences, but is at fault when, from the physical, we pass into the moral world, and we have seen how the materialistic doctrine fails when it endeavours to attach the physical to the mental. There are then two great difficulties which the materialistic explanation finds