Occam would presume, as most do, that we are the first sufficiently advanced, detectable, species to leave the gravitational well we were born in, and the first

Occam would presume, as most do, that we are the first sufficiently advanced, detectable, species to leave the gravitational well we were born in, and the first in the observable universe, so far. There is more to the universe than what we can observe, our light cone is a fraction of the expected higher bound, assuming a finite universe. We are also one of the first generation of planets with heavy elements - decreasing the odds of a species originating before us. But the universe will be around for a long, long time; Far, far longer than it has so far. We may be the first, but to assume a filter at this point is an anthropomorphic bias so ingrained it's nearly impossible to cognitively self-reflect on.