The idea that we have "no idea" what life could look like out there in the universe is grossly oversold. We actually can put a lot of bounds on them, using rigo

The idea that we have "no idea" what life could look like out there in the universe is grossly oversold. We actually can put a lot of bounds on them, using rigorous mathematics, and discuss them despite not necessarily knowing all the chemical details. Do you have any sources that discuss this?