Now it does not seem that such a process as this is likely to be free from error: and, indeed, no one pretends that it is. In fact there is scarcely any point upon which moralisers have dwelt with more emphasis than this, that man’s forecast of pleasure is continually erroneous. Each of us frequently recognises his own mistakes: and each still more often attributes to others errors unseen by themselves, arising either from misinterpretation of their own experience, or from ignorance or neglect of that of others.
How then are these errors to be eliminated? The obvious answer is that we must substitute for the instinctive, largely implicit, inference just described a more scientific process of reasoning: by deducing the probable degree of our future pleasure or pain in any given circumstances from inductive generalisations based on a sufficient number of careful observations of our own and others’ experience. We have then to ask, first, how far can each of us estimate accurately his own past experience of pleasures and pains? secondly, how far can this knowledge of the past enable him to forecast, with any certainty, the greatest happiness within his reach in the future? thirdly, how far can he appropriate, for the purposes of such forecasts, the past experience of others?
As regards the first of these questions, it must be remembered that it is not sufficient to know generally that we derive pleasures and pains from such and such sources; we require to know approximately the positive or negative degree of each feeling; unless we can form some quantitative estimate of them, it is futile to try to attain our _greatest possible_ happiness--at least by an empirical method. We have therefore to compare quantitatively each pleasure as it occurs, or as recalled in imagination, with other imagined pleasures: and the question is, how far such comparisons can be regarded as trustworthy.
Now for my own part, when I reflect on my pleasures and pains, and endeavour to compare them in respect of intensity, it is only to a very limited extent that I can obtain clear and definite results from such comparisons, even taking each separately in its simplest form:--whether the comparison is made at the moment of experiencing one of the pleasures, or between two states of consciousness recalled in imagination. This is true even when I compare feelings of the same kind: and the vagueness and uncertainty increases, in proportion as the feelings differ in kind. Let us begin with sensual gratifications, which are thought to be especially definite and palpable. Suppose I am enjoying a good dinner: if I ask myself whether one kind of dish or wine gives me more pleasure than another, sometimes I can decide, but very often not. So if I reflect upon two modes of bodily exercise that I may have taken: if one has been in a marked degree agreeable or tedious, I take note of it naturally; but it is not natural to me to go further than this in judging of their pleasurableness or painfulness, and the attempt to do so does not seem to lead to any clear affirmation. And similarly of intellectual exercises and states of consciousness predominantly emotional: even when the causes and quality of the feelings compared are similar, it is only when the differences in pleasantness are great, that hedonistic comparison seems to yield any definite result. But when I try to arrange in a scale pleasures differing in kind; to compare (_e.g._) labour with rest, excitement with tranquillity, intellectual exercise with emotional effusion, the pleasure of scientific apprehension with that of beneficent action, the delight of social expansion with the delight of æsthetic reception; my judgment wavers and fluctuates far more, and in the majority of cases I cannot give any confident decision. And if this is the case with what Bentham calls ‘pure’--_i.e._ painless--pleasures, it is still more true of those even commoner states of consciousness, where a certain amount of pain or discomfort is mixed with pleasure, although the latter preponderates. If it is hard to say which of two different states of contentment was the greater pleasure, it seems still harder to compare a state of placid satisfaction with one of eager but hopeful suspense, or with triumphant conquest of painful obstacles. And perhaps it is still more difficult to compare pure pleasures with pure pains, and to say how much of the one kind of feeling we consider to be exactly balanced by a given amount of the other when they do not occur simultaneously: while an estimate of simultaneous feelings is, as we have seen, generally unsatisfactory from the mutual interference of their respective causes.