Life is the aspect of existence that processes, acts, reacts, evaluates, and evolves through growth (reproduction and metabolism). The crucial difference between life and non-life (or non-living things) is that life uses energy for physical and conscious development. Life is anything that grows and eventually dies, i.e., ceases to proliferate and be cognizant. Can we say that viruses, for example, are cognizant? Yes, insofar as they react to stimuli; but they are alive essentially because they reproduce and grow. Computers are non-living because even though they can cognize, they do not develop biologically (grow), and cannot produce offspring. It is not cognition that determines life, then: it is rather proliferation and maturation towards a state of death; and death occurs only to living substances.
Or is the question, ‘What is the meaning (purpose) of life?’ That’s a real tough one. But I think that the meaning of life is the ideals we impose upon it, what we demand of it. I’ve come to reaffirm my Boy Scout motto, give or take a few words, that the meaning of life is to: Do good, Be Good, but also to Receive Good. The foggy term in this advice, of course, is ‘good’; but I leave that to the intuitive powers that we all share.
There are, of course, many intuitively clear examples of Doing Good: by retrieving a crying baby from a dumpster; by trying to rescue someone who’s drowning. Most of us would avoid murdering; and most of us would refrain from other acts we find intuitively wrong. So our natural intuitions determine the meaning of life for us; and it seems for other species as well, for those intuitions resonate through much of life and give it its purpose.
