There exists a problem of the circularity in measurement: construction of theories requires reliable data, but obtaining reliable data requires reliable measurement devices whose construction requires a theory. I argue that adapting Anil Gupta's empiricist epistemology to a scientific context yields a possible solution. One can consider the role of data not as providing a foundation for a theory, but as acting functionally, licensing revisions of a previous theory. Data provide scientists with entitlement to their claims conditional on their background theory. Unconditional entitlement is obtained when different starting theories converge to the same view over the course of experimentation. I explain this idea using two examples, one in thermometry and one involving experiments on the weak neutral current.