Chrillze wrote...
1. it has to be composed of cells and 2. it has to be able reproduce. the Geth are not composed of cells and they can't reproduce
A dead person is composed of cells.
There are humans whom aren't fertile.
I found this definition of life, which I think could potentially apply to future machines:
The physical, mental, and spiritual experiences that constitute existence: the artistic life of a writer. The fact of the matter is: we're all debating this because there is no answer yet. As a matter of fact, it wasn't until the 20th century when scientists could agree that animals indeed are alive. Before that, many thought that animals were genetic machines, solely acting by predictable instincts, "genetic programming", completely unable to feel emotions, thus making it ethically defendable to for example push horses off cliffs to get a good shot in a movie, or to perform particularly cruel animal tests. We might one day find that mechanical life is conceived as such a certainty, that younger generations will look down upon us for even doubting it.
That being said, I still sympathise more with the Quarians than Geth. In ME3, it's clearly shown that some Quarians wanted to help the Geth. But as there are no Quarians on Rannoch, that means that all of them, even the collaborators were exterminated by the Geth.