Earth has life. That should be a starting point for discussion. Whether there is life elsewhere is open for discussion. Whether another planet exists that allows life to reach the humble heights of our own intelligent selves is also open for discussion.
It doesn't matter whether or not there is other life out there. Our job is to get out there and explore and exploit resources to the best of our abilities.
If there is any other life out there, we will have to cross that bridge whwen we find it.