Carbon chauvinism

Carbon chauvinism is a relatively new term meant to disparage the assumption that extraterrestrial life will resemble life on Earth. In particular, it would be applied to those who assume that the molecules responsible for the chemical processes of life must be constructed primarily from carbon. It suggests that, as carbon-based life forms who have never encountered any life that has evolved outside the earth’s environment, human beings may find it difficult to envision radically different biochemistries. The term was used as early as 1973, when Carl Sagan described it and other human chauvinisms that limit imagination of possible extraterrestrial life in his Cosmic Connection.

The term may be criticized as inaccurate since chauvinism is usually defined as unreasonable belief in superiority while there is a strong basis for the belief that all life must use carbon as the central atom to construct the molecular structures that form all the complex mechanism of life. From a chemical standpoint only it seems to have the right balance of stability and reactivity to form very complex molecular structures needed for cell machinery. These structures include the cell membrane composed of mainly oflipids that separate the cell interior from its surroundings. DNA and RNA composed of nucleic acids for storage, transcription, and translation and of genetic data. An incredibly large and varied number of proteins composed of amino acids perform most all the other cellular functions including enzymes that catalyzing chemical transformations. There are also a wide variety of small molecules that play a support role in regulation of biological systems and chemical communication between cells. All other atoms seem to have fatal flaws that exclude their use in all these roles and no one has yet proposed a theory using another atom that that would form all the cellular structures necessary. It is likely that life evolving in an environment isolated from ours would function with some significant differences to ours, such as the opposite chirality or different energy cycle, but it is difficult to see how any other atom could be used to build all these structures.

In a 1999 Reason magazine article discussing the theory of a fine-tuned universe, Kenneth Silber quotes astrophysicist Victor J. Stenger using the term:

There is no good reason, says Stenger, to "assume that there's only one kind of life possible" - we know far too little about life in our own universe, let alone "other" universes, to reach such a conclusion. Stenger denounces as "carbon chauvinism" the assumption that life requires carbon; other chemical elements, such as silicon, can also form molecules of considerable complexity. Indeed, Stenger ventures, it is "molecular chauvinism" to assume that molecules are required at all; in a universe with different properties, atomic nuclei or other structures might assemble in totally unfamiliar ways.

See also

• Anthropocentrism
• Chauvinism
• Chemical evolution
• Carbon-based life
• They're Made Out of Meat