This would be the movement of value if value were simply positive: beyond a certain point, additions to the stock would _add_ no value, but they would not cause any _loss_ of value, and the highest point would come last in the series. But there is another, and a negative element in value. It arises from the indifference which we naturally feel towards goods. To man only the human is really important: by nature his thought, his sympathy is for himself; for _things_ he only cares, in the first instance, as he finds in them any relation to human interests. This interest may take the form of sympathy with pain or pleasure in the animal world; or that of religious and poetic feeling suggesting the unity of all life; or, lastly, that of economic valuation finding in things the auxiliaries and conditions of human wellbeing. This natural indifference is so great that it requires a peculiar compulsion before we look at anything outside us as having importance or value. Simple utility is not enough: if useful things are present in superfluity, we think no more of them than we do of the sand on the sea shore. It is only when our wellbeing is not assured that an interest awakens in the things on which it is seen to depend, and that we exert ourselves to acquire these things. The overcoming of this natural resistance, then, is something with which we have to reckon. The greater our need, the less the resistance: in cases of extreme need, it disappears altogether, and we identify our fate with the fate of the goods which “are life or death to us.” The resistance is at its height when we have everything in excess, and feel no thanks due to goods which cannot help ministering to our enjoyment—for there is no reason why we should value additional goods unless they give us additional wellbeing. Between these two extremes, the interest we transfer to goods is proportioned to the interest we take in what they do for us. But we do not attach to them the whole of the interest they really have for us: we do not require to do so, for goods of a stock are not estimated according to their actual importance, but according to the marginal utility they afford. All utility over the marginal utility is kept back from the value of the goods, and this gives us the figures for the strength of the resistance: the negative element is equal to the surplus value deducted. Thus, when the stock consists of two goods, the actual gratification is 10 + 9 = 19, while the calculation of the value is 9 × 2 = 18, leaving a surplus of 1: when the stock consists of 4 the actual gratification is 10 + 9 + 8 + 7 = 34, but the value is 7 × 4 = 28, leaving a surplus of 6, and so on. Putting these two scales together we have the following— 1 2 3 4 5 6 7 8 9 10 11 ------------------------------------------------------- Positive (+) 10 19 27 34 40 45 49 52 54 55 55