If that's a literally accurate description, then I am indeed aphantasic. Because I don't actually "see" anything. I can describe it as if I were seeing it. I know what d orbitals look like, and benzene rings, and rotating hypercubes and hyperspheres. But there's no experience of a "second monitor, separate from his visual input stream".

It does remind me of blindsight. That is, people who complain of blindess, but obviously do react to visual input.