Assuming that 480 mm (one-in-five, 20%), habitable planets evolve indigenous organic strains, while one in a thousand (.001) well-situated Earth-type planets matures at least one Advanced Extraterrestrial Civilization (AETC) –a high-tech culture capable of interstellar communication, perhaps quantum-physical telesponding– then (pace Frank Drake) over a typical galaxy’s coherent span of c. 12.5 billion years-to-date our Island Universe’s number of star-faring AETCs becomes a minimum .20 × 10^-4 × 2.4 × 10^9 = .48 × 10^5 = 48,000 per Milky Way-type galaxy.

To answer Fermi’s 1950 question, Where are they? we reply: Our galaxy, thereby Minkowski’s visible Universe, is very young, while star-faring super-cultures are widely dispersed in space-and-time. This is fortunate, because all full-fledged star-farers pose existential threats to developing competitors. (Think Earth’s socio-culturally imbalanced technological advances over the negligibly short time-span from AD 1750 to 2000+.) Though isolated AETCs in the Milky Way alone may already have appeared by tens of thousands, these cultures rarely if ever interact.

In this respect, I think you will find him to be typical of your respondents, although, of course, they will all be mistaken.

Denver is of a second type: not prejudging the extra-terrestrials, but wary of their power. There will be more like him, too, but far fewer than the Kjellerups.