Let us distinguish function and tendency more sharply than we have hitherto done. The pleasure-principle is then a tendency which subserves a certain function—namely, that of rendering the psychic apparatus as a whole free from any excitation, or to keep the amount of excitation constant or as low as possible. We cannot yet decide with certainty for either of these conceptions, but we note that the function so defined would partake of the most universal tendency of all living matter—to return to the peace of the inorganic world. We all know by experience that the greatest pleasure it is possible for us to attain, that of the sexual act, is bound up with the temporary quenching of a greatly heightened state of excitation. The ‘binding’ of instinct-excitation, however, would be a preparatory function, which would direct the excitation towards its ultimate adjustment in the pleasure of discharge. In the same connection, the question arises whether the sensations of pleasure and ‘pain’ can emanate as well from the bound as from the ‘unbound’ excitation processes. It appears quite beyond doubt that the ‘unbound’, the primary, processes give rise to much more intense sensations in both directions than the bound ones, those of the ‘secondary processes’. The primary processes are also the earlier in point of time; at the beginning of mental life there are no others, and we may conclude that if the pleasure-principle were not already in action in respect to them, it would not establish itself in regard to the later processes. We thus arrive at the result which at bottom is not a simple one, that the search for pleasure manifests itself with far greater intensity at the beginning of psychic life than later on, but less unrestrictedly: it has to put up with repeated breaches. At a maturer age the dominance of the pleasure-principle is very much more assured, though this principle as little escapes limitations as all the other instincts. In any case, whatever it is in the process of excitation that engenders the sensations of pleasure and ‘pain’ must be equally in existence when the secondary process is at work as with the primary process.