Disclosure of prognosis in end-of-life care is a practice that is widely and increasingly recommended. However, prognostic disclosure is known to be resisted by many dying persons and by physicians, who instead engage in a "collusion of silence"-discussing prognosis either not at all or in vague, indirect terms. Debates about the ethics of prognostic disclosure and non-disclosure have tended to focus on their relative benefits and harms, or on the psychological acceptability of prognostic information to dying persons. Unaddressed, however, is a more fundamental assumption upon which the practice of prognostic disclosure depends: that prognostic certainty is what dying persons ultimately need. In this essay I question this assumption. Reflecting on the experience of my father's recent death, I argue that prognostic certainty is not only unattainable but existentially irrelevant to many dying persons, and that prognostic uncertainty can be a greater need. Respect for individuals' existential need for uncertainty justifies prognostic silence and enables dying persons-as well as the loved ones and clinicians who care for them-to be open to new possibilities of finding meaning at the end of life.