We Never Know
No Slack
Being life is(said to be) a chemical reaction, and the building blocks of life are throughout the universe(I say throughout because they have been found in meteors, etc. so we know they don't only exist here), doesn't it stand to reason other life should exist (or should have existed) throughout the universe being there are billions of other galaxies with solar systems with planets in a "goldie locks zone" billions of years older than earth?