Seems a big title really, though I'm not sure this will be a big post.
Okay, lets say you have A, which passes a chemical process to B which passes a chemical process to C, which snatches some chemicals out of it's local environment and pushes them to A.
So you've got this loop.
Is life A, B & C?
I'd argue no. Life is actually the pattern between A, B & C. A, B & C are just the materials the pattern is rendered with.
I think the question is, do patterns (or at least this type of pattern) exist, or just some sort of delusion being pimped? I think life is pretty rare (outside of this planet), but so are some cosmological events. However, life could potentially extend to other planets, while a strange sort of sun or odd orbit of planets will just remain as is (or collapse). However, this does make me think of both cancer (spreading wantonly) and black holes (while the remain the same, their overall effect does want to spread itself around).
I don't have much more to add really, just leaving those question marks there.
But lets take the pattern as being the case. What's interesting is when you change to 'A life'. To a particular life, I think the material matter. Take for example if someone is atomically cloned. This isn't a cellular cloning, where you take a cell with genetic material and let it grow and split and grow, doing the job it does and pretty much ending up with a result much like it's original. No, atomic cloning is where you have some fantastic machine that reads each molecule and much like a photocopier but in 3D and...err, atomically, it builds an exact duplicate (well, as exact as the machine can manage - which is beyond cellular cloning and certainly beyond human detection). So, few, after all that there's a duplicate of another life. Is it the same life? It's the same pattern of life. Can you just kill the original?
Here I think I'll reference causal destiny, simply because it's a cool sounding name. The original life form comes from the birth delivered by another life form, which came from...well, you can see where I'm going. This going back and back, until you hit where a repeating pattern suddenly found itself rendered on a cooling planet. The planet itself, which birthed the chance for rendering, if you go back it's space dust. Then back and back, eventually to the big whatever the hell happened. And then back prior to that or whatever.
Meanwhile the atomic clone - well, lets say the machine has a number of blocks provided to it, full of molecules of various types to draw from in it's process. Kind of like ink in a printer. You look at the history of these blocks and well, it's not the same dealio, obviously.
So, why take this very moment as the whole sum of what you are? To do so means the atomic clones are interchangeable with the original. But if you take the history as being part of the being, that's just not in the atomic clone. No disrespect to atomic clones out there - this is a much separate time line. It's not just that the atomic clone can't pass for the original, it's also that the original can't pass for the atomic clone. Even though to our feeble short term senses and perception, they can.