Barbara Kingsolver

Though builders may build, in the main they follow the plans of architects. Teachers teach, but they must have a text. Politicians govern, but only upon the flow of commentary that raises them up or casts them down.

I can well imagine that certain writers, even writers that we'd consider today very great writers, may not necessarily have tested highly on IQ just because of their numerical skills, or maybe they may not be very good at memory, and are not particularly good at these kinds of tests.