Here are a couple more quick responses to questions by Anna Dornhaus. I have attempted to be painfully brief in the hopes of being clear and focused. As always, I’d love to hear your responses.
What makes life special?
Practically: it’s like us.
Theologically: it has God in it in a special way that inanimate stuff does not.
Ethically: it has goals that can be fulfilled or frustrated.
Biologically: it can turn not-self into self. It can also adapt to the environment and (apparently) achieve open ended advances in complexity.
How do we know it when we see it?
This is the million dollar question for astrobiologists. How would we recognize new life, if we came across it. The easiest answers are also the least likely:
It can communicate with us.
It can compete with us for resources.
It can manipulate its environment in a way inexplicable through appeal to abiotic processes (with the understanding that we constantly expand our understanding of abiotic processes).
Currently, we are focused on chemical reactions that appear very rare in the absence of biological catalysts. That means compounds unlikely to form or easily degraded found in high concentrations. The presence of molecular oxygen and ozone in an atmosphere is one such clue.