Cosmologic philosophy: mediocrity theory not reasonable (Introduction)

by David Turell , Thursday, October 07, 2021, 19:27 (929 days ago) @ David Turell

Just because we are in one small spot in the universe doesn't mean we very not very different:

https://bigthink.com/13-8/mediocrity-principle-life/

"The mediocrity principle states that if certain objects in a collection are more numerous than others, then the odds of drawing one of them is higher. The principle has been extended to apply to the existence of life in the universe: If life exists here and Earth is not a special place, then life is not special. However, applying the principle to life throughout the universe has no foundation in data and is more of a wish than a principle.

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"The mediocrity principle implies that Earth-like environments are common and, by extension, so is life. However, the steps from nonlife to life, still completely unknown, cannot be considered a straightforward consequence of Earth-like environments. A planet may have the right properties for harboring life — the right chemical composition, distance to the main star, atmosphere, magnetic field, etc. — and there would still be no guarantee that life would exist there. The fundamental mistake when applying the mediocrity principle to estimate the ubiquity of life in the universe is its starting point: to assume that Earth and its properties, including the existence of life here, are typical.

"Quite the opposite: A quick look at our solar system neighbors should dispel this notion. Mars is a frozen desert; if it had life in its early years, it didn’t offer enough stability to support it for very long. The same applies to Venus, now a hellish furnace. Farther away, there are many “Earth-like” exoplanets, but only in the sense that they have a similar mass and orbit a star at a distance that is within the habitable zone, where water, if present on the surface, is liquid. These preconditions for life are a far cry from life itself. It’s not enough that life is merely possible in another world. Life needs to be possible and exist for a long time in order to have a chance of impacting the planet’s atmospheric composition to be detectable from dozens, hundreds or thousands of light years away. So, a planet not only needs to be able to generate life, but also able to make it viable for hundreds of millions or billions of years.

"This is also the case for expectations of intelligent life elsewhere. To go from unicellular creatures to intelligent ones takes an unfathomably long time. Natural selection is not a fast process, and it depends on a series of exogenous factors that vary from planet to planet. It requires the planet to offer climatic and geochemical stability, and its parent star not to be a strong producer of life-killing ultraviolet radiation. There is nothing mediocre about this set of properties. Applying the mediocrity principle to the study of life in the universe is a mediocre move based on faulty reasoning."

Comment: Our life is very special. We may well be the only life in this universe.