The permanence of a historic idea, I have stated, is in direct proportion to the number of true ideas in its composition; the impression it makes on the organic substrata of memory is in turn in proportion to its permanence. The element of decay is the destructive effects of natural trains of thought out of accord with the logically true trains. These cause defective cerebral nutrition, which is thus seen to arise, so far as influenced by the operations of the memory, from relations of truth and error. There is a physiological tendency in the former to preserve and maintain in activity; in the latter to disappear. The percentage of true concepts which makes up the complexity of a historic idea gives the principal factor towards calculating its probable recurrence. Of course, a second factor is the physiological one of nutrition itself. The next important distinction in discussing historic ideas is between those which are held consciously, and those which operate unconsciously. The former are always found to be more active, and more amenable to correction. An unconscious idea is a product of the natural, not the logical laws of mind, and is therefore very apt to be largely false. It is always displaced with advantage by a conscious aim. One of the superficial fallacies of the day, which pass under the name of philosophy, is to maintain that any such historic idea is the best possible one for the time and place in which it is found. I am led to refer to this by the false light it has thrown on religious history. Herbert Spencer remarks in one of his essays:[236-1] “All religious creeds, during the eras in which they are severally held, are the best that could be held.” “All are good for their times and places.” So far from this being the case, there never has been a religion but that an improvement in it would have straightway exerted a beneficent effect. Man, no matter what his condition, can always derive immediate good from higher conceptions of Deity than he himself has elaborated. Nor is the highest conception possible an idealization of self, as I have sufficiently shown in a previous chapter, but is one drawn wholly from the realm of the abstract. Moreover, as a matter of history, we know that in abundant instances, the decay of nations can be traced largely to the base teachings of their religious instructors. To maintain that such religions were “the best possible ones” for the time and place is the absurdest optimism. In what a religion shares of the abstractly true it is beneficent; in what it partakes of the untrue it is deleterious. This, and no other canon, must be our guide.