I have just lifted this comment from our companion discussion board 'Trent Philosophy'
The anonymous contributor makes a bold claim. In response to the question what makes something alive he/she claims:
'Being alive is a biological phenomenon. If it has living cells then it is alive, if not then it is not'
Two thoughts here.
1. What about viruses that don't have living cells?
2. Don't we need to, after Aristotle, recognise that what makes something alive is its ability to move under its own powers or energies. There are still, after all, lots of 'living cells' in the things that are dead!
Life is surely something that 'animates' matter in a particular way. The whole philsophical question of the nature life turns on how this is possible. Is it simply a question of how matter is organised, or it a question of the presence of some distinctive force or presence?