Related to this.
We are basing what we consider natural phenomena on our observations of the galaxy.
If we were to flip the assumption from life being rare to life being pervasive, what assumed natural phenomena could in fact be evidence of life?
There is precedent for this on Earth. We are just startign to discover how much The Amazon rainforest is actually a human creation and basically a massive multi-generational bioengineering project.
This is not a serious position fo mine, btw, I know that we can track most astronomical phenomena back to fundamental laws of nature.
But equally there are some massive astronomical myseteries (dark matter/energy, certain stars being more/less common than expected etc) and I can't quite dismiss the wonder that our baseline assumptions have been tainted by this assumption.