In science, consciousness refers to a mental state of alertness or wakefulness of an individual, as opposed to, for example, someone who remains alive, but non-responsive, e.g. owing to head trauma. Various individuals have attempted to explain consciousness based on thermodynamics. In 1976, American engineer Richard Weiss postulated that: [2]

“The part of the brain which is the seat of consciousness may be a thermodynamic system no larger than a grain of sand.”

Thermodynamics
Many have attempted to explain consciousness, thermodynamically. In the 1920s, Swiss psychiatrist Carl Jung began theorizing about the consciousness and entropy, to the effect that extensity, according to one definition, is an ordering parameter of a complex system, associated with energy, defined as the area of consciousness in phase space; where phase space for the ego is a two-dimensional chart showing the relationships between consciousness, the personal unconsciousness, and the collective unconsciousness over time. [1] This work was carried over into positive positive psychology by Jung's student Mihály Csíkszentmihályi in the 1980s. [5]

In 1965, Canadian materials science engineer Jack Kirkaldy presented a Gibbs free energy theory of consciousness in his article “Thermodynamics of the Human Brain.” [6]

In 1995, American chemical engineer and physician Gerry Nahum outlined a 30-page proposal to conduct a consciousness weighing experiment, on the premise that consciousness can be quantified using (a) conservation of energy, (b) the equivalence of energy/negative entropy with neurological system information content, and (c) mass-energy equivalence. [3]

In 2007, on the premise that evolution applies to human consciousness, Indian chemical engineer DMR Sekhar postulated that DNA has a sort of consciousness, arguing for the existence of an extensive anti-entropy property of DNA called genopsych. [4]

In 2007, American chemical engineer Libb Thims explained consciousness as a type of induced movement in the human molecule, connected to changes in states of reactivity associated with the carbon atoms of the central nervous system, similar to that which happens in the process by which a retinal molecule moves in response to external forces. [7]

References
1. Schueler, Gerald J. and Schueler, Betty J. (2006). The Chaos of Jung’s Psyche, (Glossary) (T.O.C.). Online book: Schuelers.com.
2. Weiss, Richard A. (1976). Relativistic Thermodynamics, Volume 2 (pg. 142). Exposition Press.
3. (a) Nahum, Gerard. (1998). “A Proposal for Testing the Energetics of Consciousness and its Physical Foundation (25-pgs)”, Presented at an international meeting in Tuscson, AZ called Tuscon III: Towards a Science of Consciousness.
(b) ibid, Nahum. (2005). “A Proposal for Testing the Energetics of Consciousness and its Physical Foundation (33-pgs)”, Submitted for review to Consciousness and Cognition.
(c) Roach, Mary. (2005). Spook: Science Tackles the Afterlife (Gerry Nahum, pgs. 97-106, 290, 297). W.W. Norton & Co.
4. Sekhar, DMR. (2007). "On the Incompatibilities of the Second Law of Thermodynamics, Primary Instincts, Natural Selection, and the Properties of DNA." (8-pages). Submitted as article proposal to the Journal of Human Thermodynamics.
5. Csíkszentmihályi, Mihály and Larson, Reed. (1986). Being Adolescent: Conflict and Growth in the Teenage Years (section: Negentropy: Order in the Consciousness, pg. 23). Basic Books.
6. Kirkaldy, Jack S. (1965). "Thermodynamics of the Human Brain" (PDF), Biophys J. Nov. 5(6): 981-986.
7. Thims, Libb. (2007). Human Chemistry (Volume One) (consciousness, pgs. 105, 191, 200). Morrisville, NC: LuLu.

Further reading
● Seager, William. (1991). Metaphysics of Consciousness (thermodynamics, pgs. 8, 12, 34-35, 106, 110). Routledge.

External links
● Consciousness – Wikipedia.
● Are atoms conscious? (2009) – PhysicsForum.com.