In addition to purely practical values, there are cognitive values which figure in scientific deliberations. One way of introducing cognitive values is to consider the cognitive value that accrues to the act of accepting a hypothesis. Although such values may have a role to play in the matter of theory acceptance, this does not exhaust their significance in scientific decision-making. This paper makes a plea for the consideration of epistemic value—cognitive value that attaches to a state of belief. I defend the notion of cognitive epistemic value against criticisms that have been raised against it. A stability requirement for epistemic value-functions is argued for on the basis of considerations of diachronic coherence. This requirement is sufficient for proving the Value of Learning Theorem, which says that the expected utility of cost-free learning cannot be negative. Under the assumption of stability, the expected cognitive epistemic value of undergoing a learning experience must also be non-negative.