Philosophers have often noted that science displays an uncommon degree of consensus on beliefs among its practitioners. Yet consensus in the sciences is not a goal in itself. I consider cases of consensus on beliefs as concrete events. Consensus on beliefs is neither a sufficient nor a necessary condition for presuming that these beliefs constitute knowledge. A concrete consensus on a set of beliefs by a group of people at a given historical period may be explained by different factors according (...) to various hypotheses. A particularly interesting hypothesis from an epistemic perspective is the knowledge hypothesis: shared knowledge explains a consensus on beliefs. If all the alternative hypotheses to the knowledge hypotheses are false or are not as good in explaining a concrete consensus on beliefs, the knowledge hypothesis is the best explanation of the consensus. If the knowledge hypothesis is best, a consensus becomes a plausible, though fallible, indicator of knowledge. I argue that if a consensus on beliefs is uncoerced, uniquely heterogeneous and large, the gap between the likelihood of the consensus given the knowledge hypothesis and its likelihoods given competing hypotheses tends to increase significantly. Consensus is a better indicator of knowledge than "success" or "human flourishing". (shrink)