Thanks for reading and commenting, Mark. I tend to agree with your take to a point. Where it might get trickier is that all the assumptions are based on what we see as the “Goldilocks zone” conditions for life on Earth. For a planet very much like Earth to harbor life (let alone intelligent life) perhaps these conditions are a requirement. But we know so little about the universe that “life” might come in forms that we can barely guess at. Take all of the ideas in every sci-fi novel ever written: Set those up against the possibilities that might be found in such a large universe and we haven’t even considered the smallest fraction of what might be out there.