and can only get one, the pleasure which this one gives me has only half the value it would have had if the eating of it had stilled my hunger. This is the way in which we determine the value of a pleasure in life. We determine it by the needs of life. Our desires supply the measure; pleasure is what is measured. The pleasure of stilling hunger has value only because hunger exists, and it has determinate value through the proportion which it bears to the intensity of the hunger. Unfulfilled demands of our life throw their shadow even upon fulfilled desires, and thus detract from the value of pleasurable hours. But we may speak also of the present value of a feeling of pleasure. This value is the smaller, the more insignificant the pleasure is in proportion to the duration and intensity of our desire. A quantity of pleasure has its full value for us when its duration and degree exactly coincide with our desire. A quantity of pleasure which is smaller than our desire diminishes the value of the pleasure. A quantity which is greater produces a surplus which has not been demanded and which is felt as pleasure only so long as, whilst enjoying the pleasure, we can correspondingly increase the intensity of our desire. If we are not able to keep pace in the increase of our desire with the increase in pleasure, then pleasure turns into displeasure. The object which would otherwise satisfy us, when it assails us unbidden makes us suffer. This proves that pleasure has value for us only so long as we have desires by which to measure it. An excess of pleasurable feeling turns into pain. This may be observed especially in those men whose desire for a given kind of pleasure is very small. In people whose desire for food is dulled, eating easily produces nausea. This again shows that desire is the measure of value for pleasure. Now Pessimism might reply that an unsatisfied desire for food produces, not only the pain of a lost enjoyment, but also positive ills, agony, and misery in the world. It appeals for confirmation to the untold misery of all who are harassed by anxieties about food, and to the vast amount of pain which for these unfortunates results indirectly from their lack of food. And if it wants to extend its assertion also to non-human nature, it can point to the agonies of animals which, in certain seasons, die from lack of food. Concerning all these evils the Pessimist maintains that they far outweigh the quantity of pleasure which the food-instinct brings into the world. There is no doubt that it is possible to compare pleasure and pain one with another, and determine the surplus of the one or the other as we determine commercial gain or loss. But if Pessimists think that a surplus on the side of pain is a ground for inferring that life is valueless, they fall into the mistake of making a calculation which in actual life is never made.