ABSTRACT: However much privacy we may enjoy in our thinking, as human beings, we are not cognitively isolated from each other. Indeed, it has been argued that the human capacity for joint attention—consciously shared awareness of some feature of reality—is what sets our species apart from all others. But it is not easy to explain how joint attention is established. The leading account of joint attention, due to Michael Tomasello, invokes the notion of a “bird’s eye view” on the situation, a notion which seems compelling, but also difficult to square with Tomasello’s own theory of our mature self-conception as inevitably fallible judges of reality. Meanwhile, Harvey Lederman has argued that there are principled obstacles to the attainment of common knowledge, given some very plausible constraints on the acuity of human judgment. This paper takes a fresh look at the relationship between our fallibility and our capacity to enter into states in which we take ourselves to be jointly aware of reality: in particular, I argue that we can make progress in understanding joint attention by looking more closely at the interlocking roles of active and passive inference in launching these states.