Theories regarding the causes of human consciousness

In his article "The Singularity, Virtual Immortality and the Trouble with Consciousness" Robert Kuhn describes five alternative explanations for consciousness, while acknowledging that other theories may also exist.

1. Consciousness is entirely physical, solely the product of physical brain, which, at its deepest levels, comprises the fields and particles of fundamental physics. This is "physicalism" or "materialism," and it is overwhelmingly the prevailing theory of scientists. To many materialists, the utter physicality of consciousness is more an assumed premise than a derived conclusion.
2. Consciousness is an independent, nonreducible feature of physical reality that exists in addition to the fields and particles of fundamental physics. This may take the form of a new, independent (fifth?) physical force or of a radically new organization of reality (e.g., ‘qualia space’ as postulated by integrated information theory).
3. Consciousness is a nonreducible feature of each and every physical field and particle of fundamental physics. Everything that exists has a kind of "proto-consciousness," which, in certain aggregates and under certain conditions, can generate human-level inner awareness. This is "panpsychism," one of the oldest theories in philosophy of mind (going back to pre-modern animistic religions and the ancient Greeks). Panpsychism, in various forms, is an idea being revived by some contemporary philosophers in response to the seemingly intractable "hard problem" of consciousness.
4. Consciousness requires a radically separate, nonphysical substance that is independent of a physical brain, such that reality consists of two radically disparate parts — physical and nonphysical substances, divisions, dimensions or planes of existence. This is "dualism." While human consciousness requires both a physical brain and this non-physical substance (somehow working together), following the death of the body and the dissolution of the brain, this nonphysical substance of or by itself could maintain some kind of conscious existence. (Though this nonphysical substance is traditionally called a “soul” — a term that carries heavy theological implications — a soul is not at all the only kind of thing that such a nonphysical substance could be.)
5. Consciousness is ultimate reality; the only thing that's really real is consciousness — everything, including the entire physical world, is derived from an all-encompassing "cosmic consciousness." Each individual instance of consciousness — human, animal, robotic or otherwise — is a part of this cosmic consciousness. Eastern religions, in general, espouse this kind of view. (See Deepak Chopra for contemporary arguments that ultimate reality is consciousness.)