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.
Yet, consciousness obviously comes with the observable as a natural part of the world. Why do we persist in treating man as something apart from nature? It's insanity.