One could not have isolated this retrovirus without knowledge of other retroviruses that's obvious. But I believe we have answered the criteria of isolation.
I think computer viruses should count as life. I think it says something about human nature that the only form of life we have created so far is purely destructive. We've created life in our own image.
My dad was vehemently opposed to electric guitars. He did not look on that kind of music as legitimate in any way.