The concept of life cannot be established without defining death.
A few decades ago, a person (or animal) was considered dead if no breathing was noticed.
Then it evolved to heart beat...
These were considered to be the definition of being alive since they could not be artificially maintained.
Nowadays, the lack of brain activity defines death... untill the moment that brain activity will be reproducible in laboratory conditions.
Remember the scene on the first Sloan movie where the android had only the torso, but they plugged it in to a bunch of wires and hoses? Was he considered to be "alive"?
Will an autonomous, self thinking and learning, robot ever be considered "alive"?