Life is a characteristic that distinguishes physical entities that do have biological processes, such as signaling and self-sustaining processes, from those that do not, either because such functions have ceased, or because they never had such functions and are classified as inanimate. Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. The criteria can at times be ambiguous and may or may not define viruses, viroids, or potential synthetic life as "living". Biology is the science concerned with the study of life.
Too often, this concern for the big picture is simply obscurantist and is put forward by people who prefer vagueness and mystery to (partial) answers. Vagueness is at times necessary and mystery is never in short supply, but I don’t think they’re anything to worship. Genuine science and mathematical precision are more intriguing than are the “facts” published in supermarket tabloids or a romantic innumeracy which fosters credulity, stunts skepticism, and dulls one to real imponderables.
John Allen Paulos, Innumeracy: Mathematical Illiteracy and its Consequences (1988), pp. 126-127
The men in the laboratory... cannot be said to observe the actual objects of their curiosity at all. ...The sense data on which the propositions of modern science rest are, for the most part, little photographic spots and blurs, or inky curved lines on paper. ... What is directly observable is only a sign of the "physical fact"; it requires interpretation to yield scientific propositions.
Susanne Langer, Philosophy in a New Key (1942)
I was particularly interested in that, in working on Jurassic Park that aspect of what are the negative parts. Because in talking with the people who were doing this kind of research what I was hearing was that the most responsible of them were deciding not to proceed down certain lines of inquiry which is really a new phase in science. Traditionally in science what the scientists themselves have said is: "I might as well do it, because if I don't, someone else will. It is going to happen inevitably." I think there's recognition now, that it's no so inevitable and it's quite conceivable that if I don't do this research neither will anyone else. It's simply too dangerous.
Michael Crichton, interview Lost World section of Beyond Jurassic Park DVD.