Page:Mind (New Series) Volume 8.djvu/390

376 HASTINGS EASHDALL : say 280 half-hours' leisure is made up of the pleasure deriv- able from the repetition 280 times of the enjoyment derivable from one half-hour's leisure. The amount of pleasure derived from an extra half-hour would of course in fact vary on different days ; but he would expect a certain average of enjoyment on each day : and it would therefore be quite intelligible to say that the pleasure derived from .50 of additional income would be exactly 280 times the pleasure derivable on an average from half an hour's additional leisure. Once again I must admit that I feel there is some- thing rather childish in such calculations which are never made in practice any more than we attempt to say by how many grains one heap of sand is bigger than another. Nevertheless, I maintain that in such cases the judgment is quantitative and might (so long as we confine ourselves to such simple cases) intelligibly be reduced to numbers. The fact that we can have a very decided and well-grounded opinion that one total is larger than the other total, while any attempt to express our comparative estimate by numbers would be the wildest and most unprofitable guess-work, does not affect the question. The difficulties in the way of any exact mensuration of pleasures seems to me to be practical rather than theoretical. Some of these difficulties are too obvious to mention, but there is one which it may be well to notice, because it is, I believe, at the bottom of many people's objection to the whole idea of a sum of pleasures. It is assumed that we cannot sum pleasure unless we suppose pleasure to be made up of a number of isolated pleasures, as though quantity were necessarily discrete. But space and time and everything that occupies space and everything that occupies time, possess quantity, and yet space is not made up of points or time of moments. Pleasure, like time and space, is a continuum. In measuring things in space and time we have recourse to arbitrarily chosen units. And in so far as we are taking account of the dura- tion of pleasures merely, the units of time are applicable also to the case of pleasures ; there is nothing essentially unmeaning in applying these units to the measurement of pleasures, and saying that a pleasure that lasts an hour is four times as great as one that lasts only for fifteen minutes. But such calculations are of little use to us, because as a rule we cannot assume that the same feelings, emotions, occupations or what not will continue to produce pleasure at the same rate for long periods which they produce for short periods. What interests us for five minutes would bore us in an hour ; and conversely things which would interest us