The origin of the logical. – What is the origin of logic in man’s head? Surely it arose out of the illogical, the realm of which must originally have been immense. But innumerable beings drew inferences in a way different from that in which we do now perished; nonetheless, they might have been closer to the truth! He, for instance, who did not know how to find ‘identity’ often enough, both with regard to nourishment and to hostile animals – that is, he who subsumed too slowly and was too cautious in subsumption – had a slighter probability of survival than he who in all cases of similarity immediately guessed that they were identical. The predominant disposition, however, to treat the similar as identical – an illogical disposition, for there is nothing identical as such – is what first supplied all the foundations for logic. Similarly, in order for the concept of substance to originate, which is indispensable to logic though nothing real corresponds to it in the strictest sense, it was necessary that for a long time changes in things not be seen, not be perceived; the beings who did not see things exactly had a head start over those who saw everything ‘in a flux’. As such, every great degree of caution in inferring, every sceptical disposition, is a great danger to life. No living being would be preserved had not the opposite disposition – to affirm rather than suspend judgement, to err and make things up rather than wait, to agree rather than deny, to pass judgement rather than be just – been bred to become extraordinarily strong. The course of logical thoughts and inferences in our brains today corresponds to a process and battle of drives that taken separately are all very illogical and unjust; we usually experience only the outcome of the battle: that is how quickly and covertly this ancient mechanism runs its course in us.