It appears that these are the questions John wants you to ask, Hazel. I suspect his response is along the lines of: "Consciousness can't be "measured" in any literal sense." Therefore, it won't be considered a "physical" thing. But it is nonetheless "real."
This is an argument against physical monism, i.e., the stance that there is no mind/body dualism, but rather that everything that exists (i.e., is "real") is "physical." The talk about EM waves "becoming" physical is really just designed to show that things can exist even if we have never discovered, measured, and "explained" them.
Therefore "science," if it wants to deal with and explain "reality," shouldn't simply disregard consciousness and ignore it on the grounds that if it can't be measured, then science can't deal with it.
Semantics. Most people think of "things" as objects, and thought as a process. Activity can be measured and observed, but it is not an object, therefore it's not a "thing".