The definition of life, as fundamental as it may seem, appears to still elude scientists.
It's because life is not a binary condition. Are viruses alive? Will the first software that passes the Turing test be alive? Is a severed finger alive while it's being rushed to the hospital to be sewn back on? Some things are more alive than others.
The best definition of death in humans is "irreversible degradation of the synapses." But if they keep your heart pumping and then take it out and put it in somebody else, was it ever dead?
So the question here is how should living organisms be defined? What consitutes life?
Whatever definition we finally come up with is going to be challenged when we finally find life on other planets. So I'm not losing any sleep over it. It's just semantics.
Once we know what life is, what is intelligent life, sentient life?
Again, this is more of a semantic issue than a scientific one. And also, again, it's not binary, it's a continuum. I've spent enough time with parrots to have no doubt about their intelligence and sentience. I can hardly dismiss the gorillas and chimpanzees who are talking to people in ASL. You just can't draw a line and say that raccoons are intelligent but koi aren't. Some animals are more intelligent than others.
Is as some biologist have stated, life feeds off of anti-entrophy or is it that life is a manifestation of higher levels of entrophy? I tend to believe the later.
These days most of the thoughtfully written definitions do indeed include--or even stress--feeding off of negative entropy.
Life is a manifestation of lower levels of entropy, not higher. Life is an extremely complex organization of an extremely local portion of the universe. Not only is the organism itself extremely complex in its organization, but evolution develops its descendants into even more complex organizations. And then they develop the ability to start organizing the parts of the external universe that are close to them!
This is a recession of entropy. Of course it all comes with a huge cost in waste heat: energy converted into its most inert form that is radiated from the lifeforms (and from their altered environment) in copious quantities. This increases the net amount of entropy in the universe. Eventually it might catch up with them.