The paper offers a discussion on William P. Alston’s epistemology of religious experience. I start with a general assessment, then propose an explanation of Alston’s main argument for a solid epistemic status of the practice of mystical perception. The explanation shows that this argument depends on whether we have reasons not to consider the practice reliable. We can divide all reasons against the mystical perception into two types. The first type of reasons is associated with the requirement of external justification. Alston believes that this requirement is not dangerous, since both mystical and sensory perception are based on an epistemic circle. I propose a critique of the circulatory thesis about the reliability of sensory perception. The second type of justification concerns the requirement of the possibility of intersubjective tests and other features of sensory perception. Alston considers it unreasonable to apply the requirement to the mystical perception. I show that there are no sufficient reasons to agree with this claim. At the end of the paper the Russian translation of Alston’s book is evaluated.