A long-standing concern (or at least a belief) about ESP, held by both skeptics and believers in the paranormal, is that if telepathy really occurs, then it might pose a threat to mental privacy. And it’s easy enough to see what motivates that view. Presumably we like to think that we enjoy privileged access to our own mental states. But if others could come to know telepathically what we’re thinking or feeling, then (among other disquieting prospects) that would mean that our sins of the heart and most embarrassing or repulsive fleeting thoughts would potentially be available for public inspection. But how well-founded is that belief or concern? To get a grip on the issues, we should begin by considering the valuable distinction (perhaps first mentioned by C.D. Broad--Broad, 1953, 1962) between telepathic (or clairvoyant) cognition and telepathic (or clairvoyant) interaction. As you would expect, every instance of the former would be an instance of the latter, but the converse doesn’t hold—that is, ESP interaction may occur without ESP cognition. To see why this matters, we must take a closer look. If telepathic cognition occurs at all, it would presumably be a form of non-sensorial knowledge about another individual’s state of mind. More specifically, it would be a state of affairs in which so-called “percipient” A comes to know something about a telepathic interaction A has with another individual B. And what kind of things might A telepathically come to know? Well, presumably, in its most robust (and most intrusively intimidating) form, A would learn what’s going on in B’s mind—that is, that B is having certain thoughts, perceptions, or emotions. But it would still be an instance of telepathic cognition—admittedly, less intimidating or threatening to one’s mental privacy—if A learned merely that B was the telepathic cause of A’s current thought or experience—that is, that B was directly influencing or interfering with A’s stream of consciousness, whether or not A’s resulting thoughts or experiences were those of B or known by A to be those of B.