For all the good work he did, this is the one misstep in Sagan's career that likely caused the most disruption: he was big on the "reptile brain inside a mammal

For all the good work he did, this is the one misstep in Sagan's career that likely caused the most disruption: he was big on the "reptile brain inside a mammal brain" hypothesis and described it quite convincingly on Cosmos. We don't have a great strategy yet for undoing the work of an effective science educator when they teach things science goes on to disprove.