I read philosophy kinda slowly, so this is as far as I got in this one. It is my understanding that consciousness is simply the latest, and maybe not the final, complexification of phenomena that are inherent in all matter and is latent in all atoms or subatomic particles until they become organized sufficiently. Whatever epiphenomena it might be, it is a level in itself but otherwise nothing special--totally natural and material.
Yes, RightWhale -- well, at least the "natural" part. However, Bauer's biological principle, which Grandpierre (rather humorously) refers to the as Aikido principle of life, is not consciousness of the epiphenomenal type, which is far-lower order, and essentially random. Epiphenomenal consciousness does not have a principle by which it can modify its own internal states, in sensitive adjustment to changes in exterior and interior conditions. There is nothing to show that epiphenomenal consciousness has a principle by which it can grasp that it is alive as an organic biological whole, or develop a sense of identity (of experience of itself), let alone self-identity.
Epiphenomenal consciousness may be a feature of inorganic nature. But for biological life, it appears woefully insufficient to explain the consciousness of the higher forms of biological life, through animals and up to man. It has been noted that even E. coli appears to generate a kind of primitive "brain" organization. By what principle can this be an epiphenomenal activity? It appears to me to be distinctly a phenomenal one. Here we see the tension between the structural and the phenomenological -- "the integrative science" of these three theorists.
But, as Descartes points out, one's own consciousness cannot be observed via the senses. With what "eye" does one see a dream? With what "ear" does one hear oneself think? Descartes realized that consciousness is not perceived but experienced -- directly and without recourse to the senses -- and therefore was not subject to the scientific process. He posited the now-famous Cartesian dualistic approach to the fundamental question of human existence, the well-known theory of mind/body duality: "I" am that entity that hears itself think (and in so doing objectfies the body). Cogito ergo sum.
It is unscientfic to state that consciousness is an epiphenomenon of brain electrochemical activity, or anything else. Consciousness as such (as opposed to mere brain electronchemistry) has never been observed, only experienced, and thus is by definition outside the scope of scientific analysis.