Robust virtue epistemology holds that knowledge is true belief obtained through cognitive ability. In this essay I explain that robust virtue epistemology faces a dilemma, and the viability of the theory depends on an adequate understanding of the ‘through’ relation. Greco interprets this ‘through’ relation as one of causal explanation; the success is through the agent’s abilities iff the abilities play a sufficiently salient role in a causal explanation of why she possesses a true belief. In this paper I argue that Greco’s account of the ‘through’ relation is inadequate. I describe kinds of counterexample and explain why salience is the wrong kind of property to track epistemically relevant conditions or to capture the nature of knowledge. Advocates of robust virtue epistemology should develop an alternative account of the ‘through’ relation. I also argue that virtue epistemology should employ an environment-relative interpretation of epistemic virtue.