The Ocean Planets Hypothesis is that intelligent beings may flourish in the interior oceans of the moons of gas giant planets — or within exoplanets — but they are trapped there:
Williams concludes, “In the end, it could be that intelligent life is not rare at all, but that it’s simply unable to communicate with us.” Indeed, it’s not just us. They may not be able to know of or communicate with any other intelligent entity anywhere.
But then a curious consequence follows — the idea that Earth is unique returns with a vengeance. [Williams writes,]
“In terms of drawbacks, the Ocean Worlds hypothesis raises the all-important Copernican Principle (aka. Cosmological Principle). If most life in the Universe is to be found inside icy planets and moons, then planet Earth, terrestrial life, and humanity are atypical and are in a unique and advantageous position to observe the cosmos – which is consistent with the Anthropic Principle.
“What’s more, it implies an imperative or even a duty for humanity to seek out life if it wants to make contact. Otherwise, the Fermi Paradox will endure because other life forms are unable to contact us. But if in so doing, we run the risk of contaminating and destroying any life we find, are we not better off letting it endure? All good questions, and one which help to frame the ethical questions that searching for extraterrestrial life raises.” – Matt Williams, “Beyond “Fermi’s Paradox” XIII: What Is the “Ocean Worlds” Hypothesis?” at Universe TodayNews, “Is intelligent life in the universe living in interior oceans of planets and moons?” at Mind Matters News
If intelligent life forms are trapped in the interior oceans of rocky moons and planets, Earth is a special planet—much better suited to space exploration.
We should give Matt Williams a copy of Privileged Planet: