Our memory is like a sieve, that with time and use holds less and less; in so far, namely, as the older we get, the quicker anything we have entrusted to our memory slips through it, while anything that was fixed firmly in it, when we were young, remains. This is why an old man's recollections are the clearer the further they go back, and the less clear the nearer they approach the present; so that his memory, like his eyes, becomes long-sighted (πρεσβυς). That sometimes, and apparently without any reason, long-forgotten scenes suddenly come into the memory, is, in many cases, due to the recurrence of a scarcely perceptible odour, of which we were conscious when those scenes actually took place; for it is well known that odours more easily than anything else awaken memories, and that, in general, something of an extremely trifling nature is all that is necessary to call up a _nexus idearum_. And by the way, I may say that the sense of sight has to do with the understanding,[15] the sense of hearing with reason,[16] and the sense of smell with memory, as we see in the present case. Touch and taste are something real, and dependent on contact; they have no ideal side. * * * * * Memory has also this peculiarity attached to it, that a slight state of intoxication very often enhances the remembrance of past times and scenes, whereby all the circumstances connected with them are recalled more distinctly than they could be in a state of sobriety; on the other hand, the recollection of what one said or did while in a state of intoxication is less clear than usual, nay, one does not recollect at all if one has been very drunk. Therefore, intoxication enhances one's recollection of the past, while, on the other hand, one remembers little of the present, while in that state. * * * * * That arithmetic is the basest of all mental activities is proved by the fact that it is the only one that can be accomplished by means of a machine. Take, for instance, the reckoning machines that are so commonly used in England at the present time, and solely for the sake of convenience. But all _analysis finitorum et infinitorum_ is fundamentally based on calculation. Therefore we may gauge the "profound sense of the mathematician," of whom Lichtenberg has made fun, in that he says: "These so-called professors of mathematics have taken advantage of the ingenuousness of other people, have attained the credit of possessing profound sense, which strongly resembles the theologians' profound sense of their own holiness." * * * * * As a rule, people of very great capacities will get on better with a man of extremely limited intelligence than with a man of ordinary intelligence; and it is for the same reason that the despot and the plebeians, the grandparents and the grandchildren, are natural allies. * * * * *