Is there a border dividing life from non-life?

While I agree that a difficult aspect of defining life is that it is an emergent property, I don't think one can draw a line. It may be more of a gradation much like the difficulty involved in defining sub-generic systematic classifcations such as species or sub-species. Are self replicating RNA molecules "alive"? They require substrates, can reproduce? How about viruses? They share even more in common with organisms many consider living but are often considered to be non-life. I doubt a fine line can be established. Probably the simplest self replicating molecules during the process of abiogenesis would not be currently recognized as "life".