Those who object in this way forget that our actions fall into two main classes: those which we have often repeated before by means of a regular series of subordinate actions beginning and ending at a certain tolerably well-defined point—as when Herr Joachim plays a sonata in public, or when we dress or undress ourselves; and actions the details of which are indeed guided by memory, but which in their general scope and purpose are new—as when we are being married or presented at court. At each point in any action of the first of the two kinds above referred to there is a memory (conscious or unconscious according to the less or greater number of times the action has been repeated), not only of the steps in the present and previous performances which have led up to the particular point that may be selected, but also of the particular point itself; there is, therefore, at each point in a habitual performance a memory at once of like antecedents and of a like present. If the memory, whether of the antecedent or the present, were absolutely perfect; if the vibration (according to Professor Hering) on each repetition existed in its full original strength and without having been interfered with by any other vibration; and if, again, the new wave running into it from exterior objects on each repetition of the action were absolutely identical in character with the wave that ran in upon the last occasion, then there would be no change in the action and no modification or improvement could take place. For though indeed the latest performance would always have one memory more than the latest but one to guide it, yet the memories being identical, it would not matter how many or how few they were. On any repetition, however, the circumstances, external or internal, or both, never are absolutely identical: there is some slight variation in each individual case, and some part of this variation is remembered, with approbation or disapprobation as the case may be.