Science is a self-correcting process. While a consensus implies a majority, what is consensus is not determined by majority vote per se , but rather by the majority being convinced (rightly or wrongly!) that something is correct. In some cases, that represents a reversal of an earlier situation. I briefly review several cases in cosmology (and astrophysics) in the last hundred years or so where the received wisdom at a particular time turned out to be wrong, leading to a new consensus. Whether that will happen for two relatively new topics remains to be seen.