WHY IS PAIN THE OPPOSITE OF PLEASURE? Several theories of pleasure and pain have substantial difficulty explaining this basic feature. Theories according to which pleasure and pain are individual sensations or features of sensations have particular difficulty, since it is difficult to understand how pairs of sensations could be opposites. Heath-wood nicely sums up the problem: "Many pairs of felt qualities (e.g., a sensation of middle C on a piano and a sensation of F# on a banjo) are in no way opposites. But if the felt quality theory is true, then some such pairs are opposites. How could that be? What could make one sensation the opposite of another sensation?" (1)
Some pairs of sensation-types, such as hot and cold, or black and white, genuinely are opposites. Sensations of pleasure and pain, however, are too heterogeneous for their oppositeness to be analogously simple. Although painful sensations are often caused by processes that are harmful to the body, this is not always the case. For example, hay fever can cause a very painful itching in the eyes without any tissue damage or infection. So it seems that the underlying causes of pleasure and pain are ill-suited to explain their oppositeness.
Heathwood attempts to solve the problem by proposing that pleasure and pain are fundamentally related to intrinsic desires. (2) "You have an intrinsic desire for something [at a time] when you just want it--when there is no reason you can give for wanting it, no further thing you want that you think it will bring you, no end for which it is a means." (3) We can introduce some definitions: S's desire for x is intrinsic at t =df S desires x at t, and S's desire for x at t does not depend on any further thing that x leads to or produces; S "just wants" x; S's desire for x has no explanation in terms of further desires, or further things S desires. S's desire for x is extrinsic at t =df; it is not the case that S's desire for x is intrinsic at t.4 S has an intrinsic aversion to p =df; S has an intrinsic desire for not-p.
The desire theory says that a person, S, takes pleasure in p if and only if S has an intrinsic desire for p and S believes that p; S is pained by p if and only if S has an intrinsic aversion to p and S believes that p.5 On a typical version of the theory, a person, S, gets pleasure at t if and only if S has an intrinsic, de re desire that p at t, and p is true at t. A person, S, undergoes pain at t if and only if S has an intrinsic, de re aversion to p at t and not-p is true at t.6
The desire theory provides a clear solution to the oppositeness problem. Heathwood writes:
On a complete [desire-based] theory ... the oppositeness of
pleasure and pain is explained. Pleasure and pain are opposites
because pleasure is explained in terms of desire, pain is explained
in terms of aversion (or desiring not), and desire and aversion are
opposites. And if aversion really is just desiring not ... then the
oppositeness of desire and aversion is, in turn, explained in terms
of the oppositeness of a proposition and its negation. (7)
Desire and aversion are opposites in a clear and intuitive way--an aversion to p is a desire for not-p--and so it is our attitudes toward the sensations that are opposites, not the sensations themselves. Furthermore, the desire view is well-suited to explaining the heterogeneity of pleasure and pain in general, as well as the fact that some pleasures do not appear to be sensory in nature at all, such as the pleasure of making a philosophical discovery. (8)
1. Pain and Aversion
This analysis of pleasure and pain in terms of desire and aversion does not do justice to the sense in which pleasure is the opposite of pain. Because sentences satisfying the schema
are analyzable in terms of "desire" sentences satisfying the schema , to be averse to something is to desire its denial. …