Yet this definition is still open to criticism. Some people argue that a machine could contain reproducible hereditary information but we wouldn't consider it alive. A more serious objection is that by this definition a virus is alive. A lot of biologists don't buy that. But it's not a cell, which many consider the fundamental unit of life, and it doesn't do the things cells do, such as metabolize, react to the environment, etc.
Life is an illusion.
Now I'm really starting to feel that six-pack. Let's set aside the question of sentient life to avoid arguments about the soul. It seems obvious that at some level all we see about us, living or otherwise, is merely a manifestation of chemical reactions and the laws of physics. In short, life is an arbitrary distinction. Life reverses local entropy.