§5. But again, if these judgments are not clear and definite, still less are they consistent. I do not now mean that one man's estimate of the value of any kind of pleasures differs from another's: for we have assumed each sentient individual to be the final judge of the pleasantness and painfulness of his own feelings, and therefore this kind of discrepancy does not affect the validity of the judgments, and creates no difficulty until any one tries to appropriate the experience of others, But I mean that each individual's judgment of the comparative value of his own pleasures is apt to be different at different times, though it relates to the same past experiences; and that this variation is a legitimate ground for distrusting the validity of any particular comparison.
The causes of this variation seem to be partly due to the nature of the represented feeling, and partly to the general state of the mind at the time of making the representation. To begin with the former: we find that different kinds of past pleasures and pains do not equally admit of being revived in imagination. Thus, generally speaking, our more emotional and more representative pains are more easily revived than the more sensational and presentative: for example, it is at this moment much more easy for me to imagine the discomfort of expectancy which preceded a past sea-sickness than the pain of the actual nausea: although I infer---from the recollection of judgments passed at the time---that the former pain was trifling compared with the latter. To this cause it seems due that past hardships, toils, and anxieties often appear pleasurable when we look back upon them, after some interval; for the excitement, the heightened sense of life that accompanied the painful struggle, would have been pleasurable if taken by itself; and it is this that we recall rather than the pain. In estimating pleasures the other cause of variation is more conspicuous; we are conscious of changes occasional or periodic in our estimate of them, depending upon changes in our mental or bodily condition. E.g. it is a matter of common remark with respect to the gratifications of appetite that we cannot estimate them adequately in the state of satiety, and that we are apt to exaggerate them in the state of desire. (I do not deny that intensity of antecedent desire intensifies the pleasure of fruition; so that this pleasure not only appears, as Plato thought, but actually is greater owing to the strength of the desire that has preceded. Still it is a matter of common experience that pleasures which have been intensely desired are often found to disappoint expectation.)
There seem to be no special states of aversion, determined by bodily causes, and related to certain pains as our appetites to their correspondent pleasures; but most persons are liable to be thrown by the prospect of certain pains into the state of passionate aversion which we call fear, and to be thereby led to estimate such pains as worse than they would be judged to be in a calmer mood.
Further, when feeling any kind of pain or uneasiness we seem liable to underrate pain of a very dissimilar kind: thus in danger we value repose, overlooking its ennui, while the tedium of security makes us imagine the mingled excitement of past danger as almost purely pleasurable. And again when we are absorbed in any particular pleasant activity, the pleasures attending dissimilar activities are apt to be contemned: they appear coarse or thin, as the case may be: and this constitutes a fundamental objection to noting the exact degree of a pleasure at the time of experiencing it. The eager desire, which often seems an indispensable element of the whole state of pleasurable activity, generally involves a similar bias: indeed any strong excitement, in which our thought is concentrated on a single result or group of results---whether it be the excitement of aversion, fear, hope, or suspense---tends to make us inappreciative of alien pleasures and pains alike. And, speaking more generally, we cannot imagine as very intense a pleasure of a kind that at the time of imagining it we are incapable of experiencing: as (e.g.) the pleasures of intellectual or bodily exercise at the close of a wearying day; or any emotional pleasure when our susceptibility to the special emotion is temporarily exhausted. On the other hand, it is not easy to guard against error, as philosophers have often thought, by making our estimate in a cool and passionless state. For there are many pleasures which require precedent desire, and even enthusiasm and highly wrought excitement, in order to be experienced in their full intensity; and it is not likely that we should appreciate these adequately in a state of perfect tranquillity.