Alien life: how would we know?
Abstract
To recognize alien life, we would have to be clear about the defining criteria of "life". Metabolism - in other words, biochemical fine-tuning - is one of these criteria. Three senses of metabolism are distinguished. The weakest allows strong artificial life (A-life): virtual creatures having physical existence in computer electronics, but not bodies, are classed as "alive". The second excludes strong A-life but allows that some non-biochemical A-life robots could be classed as alive. The third, which stresses the body's self-production by energy budgeting and self-equilibrating energy exchanges of some (necessary) complexity, excludes both strong A-life and living non-biochemical robots.
- Publication:
-
International Journal of Astrobiology
- Pub Date:
- April 2003
- DOI:
- 10.1017/S1473550403001496
- Bibcode:
- 2003IJAsB...2..121B
- Keywords:
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- autopoiesis;
- life;
- A-life;
- artificial life;
- metabolism;
- self-organization