Only that science by definition is limited to the first human observer(s). If science insists on hard evidence to make its conclusions, then it must insist that only the perceptions of human observers be admitted as evidence. Than means, quite frankly, that science is not as firm as it apparently believes itself to be.
So much for stellar astronomy.
It doesn't believe itself to be firm at all, as is self-evidence from its history. Takes pride in the lack, in fact--considers it essential.