The meaning of that phrase is “don’t assume things without evidence”. We have plentiful evidence that life should be common in the Universe - of which not the least reason is that the Universe is believed to be infinite, meaning there are countless galaxies out there nearly exactly like out own, with planets exactly like our own.
The meaning of that phrase is “don’t assume things without evidence”. We have plentiful evidence that life should be common in the Universe - of which not the least reason is that the Universe is believed to be infinite, meaning there are countless galaxies out there nearly exactly like out own, with planets exactly like our own.