[I]t is an objective fact whether a certain experience is pleasurable or unpleasurable, and relatedly whether a particular conscious individual is presently experiencing something pleasurable or painful. It is an objective fact, so we may put it, about a subjective state.

Timothy L. S. Sprigge, Is the esse of intrinsic value percipi?: pleasure, pain and value, in Anthony O'Hear (ed.) Philosophy, the Good, the True and the Beautiful, Cambridge, 2000, pp. 119–140, p. 123