PEA Soup has a good formulation of the paradox
Suppose that A’s life contains more pain than pleasure, so that his life has intrinsic value of –15 (pending what else happens). A then takes pleasure to degree 10 in the fact that he’s had a bad life. Call this pleasure P. Is P a true pleasure or a false pleasure? If it’s a true pleasure, then its intrinsic value is +20, which means A’s life has intrinsic value of +5, which means P is not a true pleasure after all. If P is a false pleasure, then P has intrinsic value of +10, which means A’s life has intrinsic value of –5, which means P was in fact a true pleasure. Paradox.