  A third and final sense of ‘priority’ in which evidence has often been thought to be prior to theory is that of epistemic priority. On this view, it is not that the task of evidence gathering either is or ought to be performed earlier in time than the task of formulating theories; nor is semantic priority at issue. Rather, the thought is that theories depend for their justification on standing in certain relations to evidence (understood here, once again, as that which is observed), but that observations do not themselves depend upon theories for their own justification. That is: (observational) evidence is prior to theory within the context of justification. This, perhaps, is the interpretation of ‘evidence is prior to theory’ on which the slogan enjoys its greatest plausibility. For it seems that our justification for believing any presently-accepted theory of natural or social science typically does depend upon suitable observations having been made, but that, on the other hand, one can be justified in taking oneself to have observed that such-and-such is the case even if there is at present no available theory as to why such-and-such is the case (and indeed, even if such-and-such's being the case is unexpected or unlikely given the theories that one presently accepts). To the extent that such a justificational asymmetry exists, there would seem to be some truth to the idea that evidence is epistemically prior to  theory.[29]  And this sort of priority might seem to be exactly what is required if evidence is to play the role of neutral arbiter among those who come to the table with different theoretical commitments.