Sartre introduces his theory of intersubjectivity in Part Three of Being and Nothingness. With this theory, Sartre presents an alternative approach to the traditional “problem of other minds,” a problem accentuated when Descartes famously identified the content of our own minds as something we know directly and with certainty. Descartes’ view calls into question our ability to ascertain the existence of other people as conscious beings like ourselves, since we cannot observe their mental states and therefore cannot have any direct knowledge of their conscious activities. To avoid solipsism, philosophers have commonly resorted to an argument from analogy. This argument first draws on our awareness of our own mental activities as accompanied by our bodily behavior. Then, by observing that same behavior in other people, we infer that similar mental activities must also accompany their behavior. Inherent in this argument is what we might call “the standard theory” of intersubjectivity, one that positions us as conscious subjects vis-à-vis the Other as our intended object. We first encounter the Other as a body that exhibits observable movements and behaviors, and because we have no direct experience of other people’s subjectivity, our knowledge of other people as conscious subjects can only be derived from an analogy between their behavior and our own.