Forgetting impressions and experiences shows the working of the tendency to keep unpleasantness from recollection much more clearly and conclusively than does the forgetting of names. It does not, of course, belong in its entirety to the category of errors, but only in so far as it seems to us conspicuous and unjustified, measured by the measuring stick of our accustomed conception--thus, for example, where the forgetfulness strikes fresh or important impressions or impressions whose loss tears a hole in the otherwise well-remembered sequence. Why and how it is in general that we forget, particularly why and how we forget experiences which have surely left the deepest impressions, such as the incidents of our first years of childhood, is quite a different problem, in which the defense against unpleasant associations plays a certain role but is far from explaining everything. That unpleasant impressions are easily forgotten is an indubitable fact. Various psychologists have observed it, and the great Darwin was so struck by it that he made the "golden rule" for himself of writing down with particular care observations which seemed unfavorable to his theory, since he had convinced himself that they were just the ones which would not stick in his memory. Those who hear for the first time of this principle of defense against unpleasant recollections by means of forgetting, seldom fail to raise the objection that they, on the contrary, have had the experience that just the painful is hard to forget, inasmuch as it always comes back to mind to torture the person against his will--as, for example, the recollection of an insult or humiliation. This fact is also correct, but the objection is not valid. It is important that one begin betimes to reckon with the fact that the psychic life is the arena of the struggles and exercises of antagonistic tendencies, or, to express it in non-dynamic terminology, that it consists of contradictions and paired antagonisms. Information concerning one specific tendency is of no avail for the exclusion of its opposite; there is room for both of them. It depends only on how the opposites react upon each other, what effects will proceed from the one and what from the other.