This relies on the assumption that the authors model of consciousness is "correct" for lack of a better term. If you accept this model, then we should be able t

This relies on the assumption that the authors model of consciousness is "correct" for lack of a better term. If you accept this model, then we should be able to agree on this conclusion, but it's not like this is the only model of consciousness out there. This is just one model of one type of consciousness that we think we can agree on. The truth is, we don't know that plants aren't conscious, just that if they are, they don't use the same mechanisms to experience it. It's like saying that life is impossible on a planet without carbon. It's possible that silicon based life exists it there somewhere, we've just never directly observed it.