Hyper-specialization is a characteristic feature of modern medicine with the consequence of classifying the various diseases of the body into unrelated categories.

Common types of doctors you might see include:

  • Family medicine
  • Internal Medicine
  • Pediatrician
  • Obstetricians/gynecologist (OBGYNs)
  • Cardiologist
  • Oncologist
  • Gastroenterologist
  • Pulmonologist
  • Infectious disease
  • Nephrologist
  • Endocrinologist
  • Ophthalmologist
  • Otolaryngologist
  • Dermatologist
  • Psychiatrist
  • Neurologist
  • Radiologist
  • Anesthesiologist
  • Surgeon
  • Physician executive


General practitioner - Gastroenterologist - Oncologist

For instance, the general practitioner takes care of the alcoholism; the gastroenterologist takes care of the liver cirrhosis while the oncologist takes care of its final complication, the cancer of the liver. The oncologist talks about cell proliferation, the farmer of fermentation, the biologist of redox state, the mother of her son’s growth, the physicist of increased entropy. To treat better our patients, we need to do translational research, unify these diverse concepts and speak a common language.


We should not be talking about 'Energy', but about 'Entropy'

One of the most problematic errors in biology has been to put forward the notion of energy not that of entropy. This stems from the fact that energy was the first notion to emerge in mechanics, chemistry and thermodynamics. The French chemist Lavoisier (1743-1794) was first a lawyer who worked as a senior tax officer. Lavoisier is also the pupil of Condillac, a grammarian. For Condillac and therefore for Lavoisier, life and chemistry must be written in simple and intelligible terms. This led him to discard old alchemist expressions like phlogiston and minium. Lavoisier named hydrogen (“gas which gives water”, in greek), oxygen (“gas which gives acidity”) and writes chemistry in words of simple and logical reactions. Lavoisier was also a follower of the Swedish chemist Torbern Olof Bergman who was the first to use very precise scales in chemistry (https://wiki.scd.unistra.fr/collections/valorisation/auteurs/bergman_torbern_info).

Lavoisier performed a crucial experiment, by separating water into oxygen and hydrogen gases using hot iron. The recombination of these two gases to form water simultaneously in France (Monge, Lavoisier) and in England (Cavendish, Priestley, Watt) was the definitive proof that water could no more be considered, as previously thought, as an element. Lavoisier is also responsible for adding to Anaxagoras' apothegm: “Nothing is created, nothing disappears”, the sentence “Everything is transformation”.

Lavoisier was partially right: the mass of water is the sum of the mass of oxygen and hydrogen. However, separation of oxygen from hydrogen is not spontaneous. Separating the two gases requires a certain amount of heat (energy) that is absorbed by the decomposition process. This notion escapes his scales.

What is Entropy?

Entropy is a measure of how much the atoms in a substance are free to spread out, move around, and arrange themselves in random ways. For instance, when a substance changes from a solid to a liquid, such as ice to water, the atoms in the substance get more freedom to move around.

1 kg water vapour has more entropy than 1 kg water which has more entropy than 1 kg ice!


The notion of energy is omnipresent in biology today. However, the key notion is not energy that never changes but rather entropy, more difficult to grasp and that could be created at will.

Mathematics is the common language of science. To elucidate biology, we need going back to the laws of physics. In the early 1830s, the French Sadi Carnot and his German counterpart Rudolf Clausius coined the word «entropy» which means «within the transformation». Sadi Carnot was working on the steam engine, and he realized that there is always dissipation of work.

If you burn 1000 calories in the boiler of the engine on the locomotive,

  • the engine will move by the equivalent of 300 calories.
  • 700 calories will be lost in the air and will travel as heat, towards the outer space in the form of infrared photons.

There is production of entropy. Entropy is a measure of energy dispersal. In other words, it is a measure of a system’s energy that is unavailable for doing useful work.

All spontaneous processes dissipate energy as heat or entropy. Such is life. Of all the relationships in physics given the title of “law”, the second law is the one for which there appears to be no exception in the whole universe. The second law requires that the entropy of any isolated system always increase. In other words, the amount of heat released by a machine can be reduced but it can never be eliminated. The notion of entropy is fundamental for informatics and for basic physics as well. For the physicists, the notions of order and of time are the consequences of the second law of thermodynamics.

If you were ever baffled by entropy, do not be disheartened. Ilya Prigogine explicitly stated “entropy is a very strange concept”.
(Prigogine I. What is entropy? Naturwissenschaften 76 (1989), 1-8).


Like any machine, life also obeys to the second law of thermodynamics. There is production of entropy in every engine including you and me. Our temperature is about constant at 37° C. We produce heat, that is to say photons which will be released in the air and will travel in the outer space. Similarly, a computer needs to release entropy in the form of heat, which will also travel to the cosmos. Nowadays, the localization of most data center is close to the North Pole in distant northern Sweden, for example. Why? Just because, here, the outside temperature is cold enough to absorb, without any temperature change, the considerable amount of heat generated by any kind of computation.

Universal physical laws connect life and the universe. This means that life is simultaneously fragile and robust. In the past, violent events have extinguished complex life many times in Earth's history. Nevertheless, life on Earth persisted for almost four billion years, that is, for about one-quarter of the universe age. After each near extinction, the spreading of life was just unstoppable.

The cell, as a material system, has to release entropy to comply with the second law. As explained above, it can release entropy in the form of heat. But, another possibility is creation of biomass because any molecule stores a certain amount of entropy. The release of entropy in the form of heat has multiple synonyms. It can be called catabolism (“destruction”, in Greek). To burn the molecules, the cell uses the oxygen and the oxidative phosphorylation located in the mitochondria.

Turning off the mitochondria have the direct consequence that entropy can no more be released as heat. Hence, the creation of a large amount of biomass for absorbing any excess of entropy. For the cell, dividing into two daughter cells is a way of doubling the entropy in full compliance with the second law. Anabolism is the scientific term used upon releasing entropy in the form of molecules. This corresponds to cell proliferation for the biologist, to fermentation in a brewery, or to growth for each mother's child. For chemists, anabolism is a reductive process, while catabolism is an oxidative one (Table 3).

Medicine shows us that our cells oscillate between two behaviors. They can burn a substrate and emit entropy in the form of heat. But they can also synthesize molecules and emit entropy in the form of chemicals that will allow cell division and production of wastes such as proteins during inflammation.

This oscillation between biomass and heat production explains the circadian cycle, the biological cycle of day and night. During the day, man works and releases his entropy in the form of heat. The temperature rises from 36.5 °C in the morning to 37.5 °C in the evening. At night, the temperature is dropping, entropy release occurs mainly in the form of biomass. The hair of the beard grows. Night is the time of secretion for many hormones. The morning erection testifies to this hormonal secretion. The cells divide at night. A dosage of lactic acid during sleep, at night, confirms the switch to the Warburg effect. Likewise, an increase in temperature at ovulation proves the link existing between entropy and women's menstrual cycle.

Heat is the main form of entropy release by mitochondria. Proliferative cells release their entropy not in the form of heat but in the form of biomass. Let us take mitochondria extracted from differentiated cells, therefore engaged in a phase of intense combustion. Let us insert them into cells which are on the contrary engaged in a phase of synthesis, in other words of multiplication. They immediately stop multiplying, switch to a combustion mode and express genes that have remained silent until then.
Elliott, R. L., Jiang, X. P., & Head, J. F. (2012). Mitochondria organelle transplantation: introduction of normal epithelial mitochondria into human cancer cells inhibits proliferation and increases drug sensitivity. Breast cancer research and treatment, 136(2), 347-354.


Table 3: lists of synonyms

Entropy released as biomass   Entropy released as heat 


Fermentation   Respiration
Anaerobic glycolysis phosphorylation   Oxidative 
Reduction (excess electrons)   Oxidation
Alcalosis (intracellular)   Acidosis (intracellular)
Low ATP synthesis   High ATP synthesis
High water activity   Low water activity

Legend: These concepts were developed by different disciplines but have similar meanings from

Schwartz, L., Devin, A., Bouillaud, F., & Henry, M. (2020). Entropy as the Driving Force of Pathogenesis: an Attempt of Diseases Classification Based on the Laws of Physics. Substantia4(2).