Talk about arrogance! Where is this empirical knowledge you claim we have?
We have exactly one data point: Earth.
Furthermore, it is the height of inanity to presume by “observation” they mean “see with a telescope.”
We have data points regarding many planets circling other stars. That’s just a fact. That they have life? No one knows that yet. When I was younger many articles theorized that no other stars have planets or that it is extremely rare. Even with limited ability, we have detected many other planets. Some are in a “habitable zone” around their star.