§7. We must conclude then that our estimate of the hedonistic value of any past pleasure or pain, is liable to an amount of error which we cannot calculate exactly; because the represented pleasantness of different feelings fluctuates and varies indefinitely with changes in the actual condition of the representing mind. We have now to observe that, for similar reasons, even supposing we could adequately allow for, and so exclude, this source of error in our comparison of past pleasures, it is liable to intrude again in arguing from the past to the future. For our capacity for particular pleasures may be about to change, or may have actually changed since the experiences that form the data of our calculation. We may have reached the point of satiety in respect of some of our past pleasures, or otherwise lost our susceptibility to them, owing to latent changes in our constitution: or we may have increased our susceptibility to pains inevitably connected with them: or altered conditions of life may have generated in us new desires and aversions, and given relative importance to new sources of happiness. Or any or all of these changes may be expected to occur, before the completion of the course of conduct upon which we are now deciding. The most careful estimate of a girl's pleasures (supposing a girl gifted with the abnormal habit of reflection that would be necessary) would not much profit a young woman: and the hedonistic calculations of youth require modification as we advance in years.
It may be said, however, that no one, in making such a forecast, can or does rely entirely on his own experience: when endeavouring to estimate the probable effect upon his happiness of new circumstances and influences, untried rules of conduct and fashions of life, he always argues partly from the experience of others. This is, I think, generally true: but by including inferences from other men's experience we inevitably introduce a new possibility of error for such inference proceeds on the assumption of a similarity of nature among human beings, which is never exactly true, while we can never exactly know how much it falls short of the truth; though we have sufficient evidence of the striking differences between the feelings produced in different men by similar causes, to convince us that the assumption would in in any cases be wholly misleading. On this ground Plato's reason for claiming that the life of the Philosopher has more pleasure than that of the Sensualist is palpably inadequate. The philosopher, lie argues, has tried both kinds of pleasure, sensual as well as intellectual, and prefers the delights of philosophic life; the sensualist ought therefore to trust his decision and follow his example. But who can tell that the philosopher's constitution is not such as to render the enjoyments of the senses, in his case, comparatively feeble? while on the other hand the sensualist's mind may not be able to attain more than a thin shadow of the philosopher's delight. And so, generally speaking, if we are to be guided by another's experience, we require to be convinced not only that he is generally accurate in observing, analysing, and comparing his sensations, but also that his relative susceptibility to the different kinds of pleasure and pain in question coincides with our own. If lie is unpractised in introspective observation, it is possible that he may mistake even the external conditions of his own happiness; and so the communication of his experience may be altogether misleading. But however accurately he has analysed and determined the causes of his feelings, that similar causes would produce similar effects in us must always be uncertain. And the uncertainty is increased indefinitely if our adviser has to recall in memory out of a distant past some of the pleasures or pains to be compared. Thus in the ever renewed controversy between Age and Youth, wisdom is not after all so clearly on the side of maturer counsels as it seems to be at first sight. When a youth is warned by his senior to abstain from some pleasure, on the ground of prudence, because it is not worth the possible pleasures that must be sacrificed for it and the future pains that it will entail; it is difficult for him to know how far the elder man call recall---even if he could once feel---the full rapture of the delight that he is asking the younger to renounce.
And further, this source of error besets us in a more extended and more subtle manner than has yet been noticed. For our sympathetic apprehension of alien experiences of pleasure and pain has been so continually exercised, in so many ways, during the whole of our life, both by actual observation and oral communication with other human beings, and through books and other modes of symbolic suggestion; that it is impossible to say how far it has unconsciously blended with our own experience, so as to colour and modify it when represented in memory. Thus we may easily overlook the discrepancy between our own experience and that of others, in respect of the importance of certain sources of pleasure and pain, if no sudden and striking disappointment of expectations forces it on our notice. Only with considerable care and attention can sympathetic persons separate their own real likes and dislikes from those of their associates: and we can never tell whether this separation has been completely effected.
But again: the practical inference from the past to the future is further complicated by the fact that we can alter ourselves. For it may be that our past experience has been greatly affected by our being not properly attuned to certain pleasures, as (e.g.) those of art, or study, or muscular exercise, or society, or beneficent action!; or not duly hardened against certain sources of pain, such as toil, or anxiety, or abstinence from luxuries: and there may be within our power some process of training or hardening ourselves which may profoundly modify our susceptibilities. And this consideration is especially important,---and at the same time especially difficult to deal with,---when we attempt to appropriate the experience of another. For we may find that he estimates highly pleasures which we not only have never experienced at all, but cannot possibly experience without a considerable alteration of our nature. For example, the pleasures of the religious life, the raptures of prayer and praise and the devotion of the soul to God, are commonly thought to require Conversion or complete change of nature before they can be experienced. And in the same way the sacrifice of sensual inclination to duty is disagreeable to the non-moral man when he at first attempts it, but affords to the truly virtuous man a deep and strong delight. And similarly almost all the more refined intellectual and emotional pleasures require training and culture in order to be enjoyed: and since this training does not always succeed in producing any considerable degree of susceptibility, it may always be a matter of doubt for one from whom it would require the sacrifice of other pleasures, whether such sacrifice is worth making.
The foregoing considerations must, I think, seriously reduce our confidence in what I have called the Empirical-reflective method of Egoistic Hedonism. I do not conclude that we should reject it altogether: I am conscious that, in spite of all the difficulties that I have urged, I continue to make comparisons between pleasures and pains with practical reliance on their results. But I conclude that it would be at least highly desirable, with a view to the systematic direction of conduct, to control and supplement the results of such comparisons by the assistance of some other method: if we can find any on which we see reason to rely.