H.M. Collins's informative study of the debate about gravity waves, recently published in this journal,' concludes on a rather bizarre note. Specifically, Collins claims to have shown that the sociologist is wise to proceed on the assumption that there is no relationship whatever between the world and our beliefs about the world. As he puts it, 'the natural world in no way constrains what is believed to be'.2 Even on the most charitable construal, this claim is wildly implausible, for it ultimately denies that our beliefs emerge out of a causal interaction with the objects of the physical world. As soon as one grants that the natural world plays a causal role in shaping our beliefs (even if it is only one among many other causes), then it must be conceded that what there is puts a great many constraints upon what it is physically possible for us to believe. To deny that what there is constrains our beliefs is to repudiate the naturalistic thesis that we are a part of the world's causal order. But the object of this note is not to quarrel specifically with Collins's relativistic antinaturalism. Its aim, rather, is to point to an apparent contradiction in Collins's mode of reaching that conclusion which is, I think, implicit in much recent sociology of knowledge. What I have in mind is the simultaneous espousal of two incompatible points of view namely, empiricism and strong relativism. In its most innocuous form, the empiricist premise amounts to the claim that we should base our theories and other beliefs about science on the available evidence; it urges that a priori speculation about science should give way to detailed, empirically-grounded case studies. (Collins's own investigation of gravity waves is a case in point.) Strong relativism, on the other hand, amounts to the claim that our beliefs about the natural world are largely, if not entirely, independent of that world. These two points of view scarcely sit well together, particularly when the thesis of strong relativism is said to be established or confirmed by the empirical case studies! The search for evidence in any field of empirical inquiry is the search for statements which reflect some features of the world. The very notion of evidence is relational. Evidence is always evidence ofsomething or other. Unless we believe there is some linkage between a statement and a certain state of affairs in the world then we refuse to regard the statement as evidential. But if the