The meaning of Life

“We are confident that embryology, biology, and a philosophically consistent view of human rights lie on the pro-life side, and look forward to making that case both on the streets and in the debate.” – Stephanie Gray

Gray structured her argument into three man categories: scientific, philosophic, and legal/ethical. The scientific part started off with two key “scientific facts,” the first of which is

If something grows, it is alive.

A staggering number of counter-examples spring to mind. The sun is currently growing in diameter, and might one day engulf our planet; does this make it alive? Snowflakes grow through random collisions with ice molecules; does this make them alive? Black holes? Planets? Crystals?

Mind you, there is another way to interpret that. Perhaps Gray meant “evolution” instead of “growth?” Even this is problematic, as I am not evolving; the genes that I pass on to my offspring do not change over time or with the environment, they were hard-wired in at conception. My immune and digestive systems are changing to adapt to the environment they live in, it’s true, but because those changes can’t be inherited they are not evolutionary. Human beings evolve as a population, not as individuals.

Still, we can be generous again. That definition can declare an entire population to be alive, which in turn implies that every individual of that population is also alive. There are still problems with this, for instance no member of a species on the brink of extinction would be alive by this definition, but these are sufficiently rare exceptions that can be swept under the rug. With a liberal, forgiving interpretation, we can turn Gray’s assertion into something reasonable.

No, wait: as I said before, there is no such thing as a scientific fact. For the third time we have to repair Gray’s statement, and claim that “growing evolving things are alive” is really a “theory with consensus support from experts” instead of a “fact.” So that statement has to be more than reasonable, it has to enjoy the support of most scientists.

It doesn’t.

Carol Cleland, a professor of philosophy at CU, grapples with these questions. She and Christopher Chyba of Princeton University are recognized authorities on the difficulty of adequately defining “life.” […]

“To answer the question ‘What is life?’ we require not a definition but a general theory of the nature of living systems,” Cleland and Chyba write. “In the absence of such a theory, we are in a position analogous to that of a 16th-century investigator trying to define ‘water’ in the absence of molecular theory.”

As Cleland and Chyba note, attempts to define life founder on counter-examples – living things that are wrongly defined as non-living, and non-living things that are incorrectly included in a flawed definition of “life.” Philosophers as old as Aristotle attempted to define “life” as something that could reproduce itself.

By that definition, mules (which are sterile) would not qualify as being alive.

Other attempts to define “life” are similarly flawed, Cleland and Chyba observe. For instance, life has been defined by metabolic standards: something with the ability to consume or convert energy to move, grow or reproduce. By that measure, fire and perhaps even cars might be deemed alive.

How can this be? “Life” is an informal definition, as I described earlier. It’s only used to describe things, not define them, and so doesn’t need to be precise. For Gray’s statement to work, though, “life” needs to be precisely defined. So no amount of generosity can fix one of Gray’s core arguments; it is simply too weak to use in any logical argument.

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