Cite as: Spacek, J. (2022) “Why the term ‘life’ is useless in astrobiology”. Primordial Scoop, e20220526. https://doi.org/10.52400/QLMZ8018
In her latest article, Carol Cleland rebutted my old post claiming that despite our inability to define ‘life’, we should NOT get rid of the term ‘life’. (Carol wrote a book about ‘life’)
Steven Benner tells us that we should NOT get rid of ‘life’ which he defines as “chemical systems capable of Darwinian evolution” and refers to things that we “value in life” (which he refuses to define). (Steven also wrote a book about ‘life’)
Carol and David Grinspoon do not agree with Steven what the ‘life’ is and I wager that Carol would not agree on any ‘life’ definition with David, and yet they all agree that ‘life’ is useful and important. (David also wrote a book about ‘life’)
‘Life’ is either undefined (Carol), or defined as “chemical systems capable of Darwinian evolution” (Steven), it could be a planetary phenomenon (David), or as large proportion of general population perceives it: ‘life’ is the thing you have after your kids leave for university.
We might as well be discussing existence of God: Carol, David, and Steven are sure that there is (at least) one, but they cannot agree on details such as if it is permissible to eat pork, or if human sacrifices are needed to increase agricultural yields. Their holy books are mutually exclusive on many topics except for the certainty of their God’s existence.
Contrary to what Carol said, I do not see any evidence of ‘life’. We have evidence of evolution, animal behavior, complex chemistry, locomotion, metabolism… As I said before, the person who claims that ‘life’ exists should provide some evidence to support that claim. It is wrong to assume existence of a thing without evidence until we have some evidence that the thing does not exist.
If you, like Steven, decide to say that ‘life’ = ‘Chemical system capable of Darwinian evolution’ (for which we have plenty of evidence), why would you keep using the two synonyms? That’s confusing and misleading especially for people using different definitions of ‘life’ than Steven.
The main point is that outside of science, general public equates ‘life’ to ‘their life’ or ‘living’. This builds up high expectations, requiring NASA to explain again and again that ‘life’ might not be little green men. There would be no need for the highly criticized (1, 2, 3, 4, 5, 6, 7, and 8) NfoLD guidelines if we, the astrobiologists, ditched the word ‘life’ and told the public what we are actually looking for and expecting to find.
After all, an announcement that we have found extraterrestrial ‘life’ is meaningless unless you provide a description of what has been found:
“We have found life on Venus!” After reading such a title, a lay person might feel strong emotions, imagining lush tropical forests and various Venusians running around in it… and then they would be inevitably disappointed if the next line past the title read: “Venusian life is limited to carbon polymers evolving in the sulfuric acid cloud droplets for about 6 months towards systems capable to assimilate carbon monoxide more efficiently. This life is destroyed as falls from the cloud. The best performing highly-evolved Venusians manage evading the “raining out” from the cloud for up to two Venusian years.”
At the other end of the spectrum, in a different (sci-fi) scenario rational Steven Benner might say:
“No, we have NOT found extraterrestrial life! -The robotic flotilla coming to devour our solar system is not replicating through Darwinian evolution and we have no evidence that it ever did, hence it is not ‘life’.”
What meaning is added by calling these two examples life and non-life?
There are things we value, such as learning new things and monitoring for potential risks. But calling a thing ‘life’ does not tell us anything about these or any other values. Complex organic chemistry in the clouds of Venus deserves to be studied regardless if we decide to call it ‘life’ or not. Alien replicators are not any less menacing if they are replicating without random mutation and natural selection.
Hence, as I said before, I believe that term ‘life’ has negative utility. It confuses the public, and hinders effective communication between scientists.
I see four reasons to use the confusing, undefined or undefinable term ‘life’ if you are an astrobiologist: (1) tradition, (2) sentimental value, (3) laziness, and (4) project financing (“Search for an extraterrestrial life” brings more emotions, attention, and money, than specified search for “disequilibrium in exoplanet atmospheres” or “genetic polymers in the Martian ice”).
Not great reasons in my opinion.
Ultimately it boils down to a cost-benefit analysis: Are we lazy enough to keep confusing other scientists and public?
A compromise could be to define ‘life’ at the beginning of our papers (“For the propose of this paper life is XYZ”). That could reduce the confusion. But this demonstrates only the issue we have with ‘life’: 100 scientists may have 100 ‘life’ definitions. Because it is known that we cannot agree on a life definition, Network for Life Detection decided to not define ‘life’ in the infamous Standards of Evidence white paper.
I wonder if the next generation of scientists will be able to get rid of this confusing tradition and exchange ‘life’ for specific defined and testable categories when debating scientific matters.
Encountering general artificial intelligence might help us to realize that the things we value in life do not include ‘life’.
