Sarah Sawyer has challenged my claim that social externalism depends on the assumption that individuals have an incomplete grasp of their own concepts. Sawyer denies that Burge's later sofa thought-experiment relies on this assumption: the unifying principle behind the thought-experiments supporting social externalism, she argues, is just that referents play a role in the individuation of concepts. I argue that Sawyer fails to show that social externalism need not rely on the assumption of incomplete understanding. To establish the content externalist conclusions, further considerations are required, and these do commit the externalist to the assumption of incomplete understanding.