 Van Fraassen replies with the recognition that “scientific realists tend to feel baffled by the idea that our opinion about the limits of perception should play a role in arriving at our epistemic attitudes toward science” (1985, 258). Constructive empiricists are not asserting any metaphysical difference in the world on the basis of the observable/unobservable distinction; they are just saying that that distinction is relevant to the epistemic attitudes we take. Since “experience is the sole legitimate source of information about the world” (van Fraassen 1985, 258), it makes sense that what we can experience influences our epistemic attitudes. (Note that in his 2002 book The Empirical Stance, van Fraassen calls into question his 1985 statement about experience.)