'Being able to think for itself' is the best argument of being alive. Right? Of course it is because you are human and only humans can think for themselves. Humans thought of this argument and thus it is the most valid argument. We can think of. But what if the definition of life was: 'Must be able to be very green'?, plants would be more 'alive' than us.
Should you feel like watching someting else than the game tonight, maybe you can consider expanding your mind and have a go at this lecture.