Re. Tara de Costa's query about the aliveness of viruses: I would not put
it as crude as Steven Harwood ("to live is to excrete") but he has a point!
Selection pressure comes in there somewhere! I like Steven Levy's ("Artifi-
cial Life", Penguin Books 1993) suggestion that perhaps we should look at
the difference between "life" and "dead" more as a diffuse transition, viruses
being more alive than rocks and less alive than their hosts... Any suggestions?
Greetings from bonny Scotland,
Denni (ds4 at st-and.ac.uk)