Richard Jenkyns, Virgil's Experience. Nature and History: Times, Names, and Places
(Oxford: Oxford University Press, 1998), p. 262:
The fact that Epicurus placed a comparatively low value on what the man in the street considers to be pleasure may be surprising, but it is not illogical. Epicurus holds that we live in an imperfect world, that we are creatures liable to pleasure and pain, that we have potentially disorderly appetites, and that we must make the best sense we can of the situation in which we find ourselves. Given these premisses, the conclusion that we shall live best by moderating our physical appetites and developing purely mental pleasures is in no way contrary to reason. Some may think this approach to life pusillanimous, a failure of nerve; others may reckon that whether it be right or wrong, the idea that the greatest happiness is to be found in the absence of pain and a calm of mind fortified by the pleasures of friendship and memory is neither ignoble nor obviously absurd.31
31 Age may influence judgement. At the age of 20 Epicurus' idea of happiness might seem wildly unreal, at 40 not unreasonable, at 90 plain common sense. Experience will also have its effect. Convalescence after serious illness can produce moments of pure felicity that seem at the time to surpass any kinetic pleasure. (Beethoven's Heiliger Dankgesang (on recovery from illness), containing perhaps the finest realization of pure serenity in art, seems to express this feeling.) It is a mental experience inseparable from bodily experience, a gratitude for being an animal.