Unaddressed is the scenario wherein multiple filters exist. One or more could be behind us; one or more ahead. And so, not finding life on Mars or Titan or anything nearby would be nothing to celebrate.
> Nothing in the above reasoning precludes the Great Filter from being located both behind us and ahead of us. It might both be extremely improbable that intelligent life should arise on any given planet, andvery improbable that intelligent life, once evolved, should succeed in becoming advanced enough to colonize space.
Unaddressed is the scenario wherein multiple filters exist. One or more could be behind us; one or more ahead. And so, not finding life on Mars or Titan or anything nearby would be nothing to celebrate.