Re: Best petri dish
This. A million times this.
There are no trees on the Moon. No "rivers" on Mars. Thus, not all places are exactly the same as here. Assuming an infinite universe.... assumes an infinite universe (and unicorns and all that).
We might be common, we might be unique, and a TON of science is needed between the two to know which is which (and scarily, without extra data, we may never know, in a scientific means).