Yeah he could have done. Doesn't he talk about people hooking their minds up to artificial intelligences or something? That sounds like a transhuman concept to me. Interestingly, his opinion on what is more feasible- building a pure AI or building cyborgs- is at odds with Vernor Vinge. Whereas Harris argued here that it would be easier to build a pure AI (no having to figure out how to interface that with biological brains), Vinge took the opposite view, writing "it's very likely that IA (it stands for Intelligence Amplification) is a much easier road to the achievement of superhumanity than pure AI. In humans, the hardest development problems have already been solved. Building up from within ourselves ought to be easier than figuring out what we really are and then building machines that are all of that".