Cosmology and the mediocrity principle

[otseng]

The mediocrity principle is the philosophical notion that "if an item is drawn at random from one of several sets or categories, it's likelier to come from the most numerous category than from any one of the less numerous categories" (Kukla 2009).[1] The principle has been taken to suggest that there is nothing very unusual about the evolution of the Solar System, the Earth, humans, or any one nation. It is a heuristic in the vein of the Copernican principle, and is sometimes used as a philosophical statement about the place of humanity. The idea is to assume mediocrity, rather than starting with the assumption that a phenomenon is special, privileged or exceptional.[2][3]

http://en.wikipedia.org/wiki/Mediocrity_principle

Current cosmology assumes that the mediocrity principle is true. Our solar system, the earth, and humans are not special. But, is this assumption true? Why or why not?

[DanieltheDragon]

[Replying to post 1 by otseng]

Time will tell really I don't think with our current knowledge we can answer one way or the other.

There is likely not going to be two systems with homo sapiens in it so in that respect we are special I guess but who knows what life is out there in the universe. It is a BIG BIG place and we can only observe a very very very insignificant amount of it.

The likely answer is our particular solar system and civilization is nothing particularly unique or special. I say this because of the sheer size of the universe. The Kepler telescope answered a lot of questions in this regard before it broke, but it also generated more questions than it answered. The James-Webb telescope will be really exciting in this regard being able to peer deeper into space than we ever have before. There is also a satellite being designed to directly observe planets surrounding stars.

Based on the Kepler results we can estimate that there is 40,000,000,000+ earth sized planets orbiting in habitable zones in our galaxy alone. So with an estimated 100 billion galaxies in the universe. we are just an insignificant spec among the possible iterations of life.

[Divine Insight]

Current cosmology assumes that the mediocrity principle is true. Our solar system, the earth, and humans are not special. But, is this assumption true? Why or why not?

I'm not in agreement with you that modern day cosmology assumes mediocrity as a necessary foundational premise. On the contrary, I feel that this principle has actually come to be accepted from actual observational data.

I basically began with Copernicus and Galileo when it became apparent that the Earth as no the center of the solar system. The idea that the Earth was the center of the solar system certain gave the Earth a privileged and special place in the universe. After all being the center of the universe indeed pretty darn special.

But with the discovery that the earth actually obits around the sun along with all the other planets and only the Earth's moon orbits the earth, the suddenly Earth's position in this solar system is indeed mediocre and not special at all.

Of course, even then the stars were thought to be something different from the sun. We soon realized that stars are just other suns. So not only has the Earth become mediocre but so has the Sun and our entire solar system.

Thanks to Edwin Hubble, we soon learned that not only are the stars distant suns, but some specks of light in the night sky are actually distant galaxies which are full of stars not much different from our sun. And there are billions of galaxies.

So what did we discover about the earth? Well, we basically discovered as an observable fact the following:

• The Earth is not the center of the universe or "creation".
• The Earth is not even the center of the solar system.
• The Sun is not unique or special either.
• The entire solar system does not even reside in a special place in the Milky Way Galaxy.
• The Milky Way Galaxy is not even unique or special in terms of the observable universe at large.

We basically live in a totally mediocre speck of dust in a universe where we cannot lay claim to being special in any possible way. We can't even claim to be special in terms of life, because we can't know whether there is life on other planets or not. And there's really no reason for us to guess that there isn't. On the contrary, as far as we can see the universe is made of the same stuff everywhere governed by the same laws. Therefore it would be foolish to believe that only Earth contains life.

So I don't see where cosmology "depends" upon any "assumptions" of a principle of mediocrity, on the contrary the principle of mediocrity appears to have been observationally confirmed by cosmological observations.

Now "cosmological theories" may embrace this observationally confirmed property of our universe. But that's hardly a dependence upon any assumptions.

~~~~~

If you disagree with this then can you show how the earth is "special" in any known way?

You can't just point to sentient life on Earth and claim that we don't see this anywhere else, because we don't have the ability to say that life doesn't exist on other planets in this universe. Life could potentially exist on other planets even within our own Milky Way galaxy and we would have no way of knowing that.

So what reason would anyone have for suggesting that the earth is special? Special in what way? It's already been shown to be quite mediocre in every observable way.

[otseng]

I'm not in agreement with you that modern day cosmology assumes mediocrity as a necessary foundational premise. On the contrary, I feel that this principle has actually come to be accepted from actual observational data.

I would disagree with this. But, before I get into why, I'll add that there are at least two things that derive from the mediocrity principle: the Copernican principle and the Cosmological principle.

"In physical cosmology, the Copernican principle, named after Nicolaus Copernicus, states that the Earth is not in a central, specially favored position in the universe."
http://en.wikipedia.org/wiki/Copernican_principle

"The cosmological principle [means that] the universe looks the same whoever and wherever you are."
http://en.wikipedia.org/wiki/Cosmological_principle

Rather than the data supporting the mediocrity principle, data is often interpreted through the lens of the mediocrity principle. Theories are created to make sure that the mediocrity principle is upheld.

The assumption that the earth is not in a special position actually cannot be proven.

"The Copernican principle has never been proven, and in the most general sense cannot be proven, but it is implicit in many modern theories of physics."
http://en.wikipedia.org/wiki/Copernican_principle

So, contrary to your claim, it is an assumption and it is of vital importance in current cosmology.

I liken it to the Greeks upholding the ideal of the circle. They assumed that things must move in circles. But, soon they started noticing some problems (retrograde motion). So, they added complex epicycles to account for them. They had no evidence really that things moved in epicycles, but it allowed them to keep their circles. Likewise, modern cosmology assumes mediocrity, but it has to keep adding things that have no evidence to support them to keep the mediocrity assumption true.

[stcordova]

Big Bang cosmology assumes that every location gives many similar observations of the rest of the universe so that no one location looks especially privileged. The terms used to describe this are "istropic and homogenous".

The cosmological principle is usually stated formally as 'Viewed on a sufficiently large scale, the properties of the Universe are the same for all observers.'

http://en.wikipedia.org/wiki/Cosmological_principle

This means there is no privileged position as a matter of principle. When the phrase "sufficiently large scale is used", that means somewhere in the ball park of 100 mega parsecs.

This is possible if the Big Bang is true.

If the Big Bang is true the universe is geometrically structured under a non-Euclidean geometry that obeys the Roberston-Walker-Friedmann-Lemaitre metric -- that means the universe has no center.

If the universe on the other hand follows something like a Euclidean geometry (the one that is most familiar to everyday life), then we may potentially live in a privileged location.

Sorry for getting technical, but that's the nature of this particular topic.

If the galaxies are moving away from us and if the Big Bang is false, then we are most certainly in a privileged position based on geometry alone (aka, we're very close to the center of the universe, the origin of a Euclidean/Cartesian X,Y,Z coordinate system).

If the galaxies are moving away from us and if the Big Bang is true, we could still be in a privileged position on the basis few locations in the universe would sustain life and scientific discovery. But such a privileged position would be based on considerations outside of geometry.

I believe the Big Bang is false, I don't know what geometry space is governed by, but I do think there aren't many places that will sustain life and scientific discovery, and thus we live on a privileged planet on that basis at least. There is a chance we live in a geometrically privileged postion, but that won't be resolved any time soon.

[FarWanderer]

I liken it to the Greeks upholding the ideal of the circle. They assumed that things must move in circles. But, soon they started noticing some problems (retrograde motion). So, they added complex epicycles to account for them. They had no evidence really that things moved in epicycles, but it allowed them to keep their circles. Likewise, modern cosmology assumes mediocrity, but it has to keep adding things that have no evidence to support them to keep the mediocrity assumption true.

Yet the culprit of the retrograde illusion wasn't the Greeks' insistence on circles, but their insistence on geocentrism. Which, ironically, was settled by the Copernican principle you're currently criticizing.

Furthermore, I don't see how the Copernican principle or the Cosmological principle are ad hoc additions to the principle of mediocrity (like the epicycles were). They're expressions of it.

[JoeyKnothead]

From the OP:

Current cosmology assumes that the mediocrity principle is true. Our solar system, the earth, and humans are not special. But, is this assumption true? Why or why not?

The problem here is in using a subjective term, special, in order to confirm an otherwise objective claim.

Is the earth special in a cosmological sense? Yes, 'cause it's got critters, and I love me some critters. But that's my criteria. I'm curious to know if Gary Gnu thinks the planet is so special, what with all the lions and such.

Is the earth special 'cause some god said so, or made it so special? Those who make such a claim are, to my knowledge, unable to confirm the claim beyond their being real proud of it.

Conclusion?

The earth is special to those who think it is, and it ain't to those who think it ain't. And both, being opinion based on a subjective notion, are simultaneously right and wrong, only some'll think they have it more right than wrong.

[Goat]

The mediocrity principle is the philosophical notion that "if an item is drawn at random from one of several sets or categories, it's likelier to come from the most numerous category than from any one of the less numerous categories" (Kukla 2009).[1] The principle has been taken to suggest that there is nothing very unusual about the evolution of the Solar System, the Earth, humans, or any one nation. It is a heuristic in the vein of the Copernican principle, and is sometimes used as a philosophical statement about the place of humanity. The idea is to assume mediocrity, rather than starting with the assumption that a phenomenon is special, privileged or exceptional.[2][3]

http://en.wikipedia.org/wiki/Mediocrity_principle

Current cosmology assumes that the mediocrity principle is true. Our solar system, the earth, and humans are not special. But, is this assumption true? Why or why not?

From a subjective point of view, it's very special, because without it being here, I wouldn't be either.

When we can travel to other solar systems, and find out how many rocky planets are in the goldilocks zone with a moon to make sure the tilt doesn't wobble too much.

[Divine Insight]

The assumption that the earth is not in a special position actually cannot be proven.

A special position with respect to what?

It has been proven beyond any reasonable doubt that it has no special physical location within the universe as a whole. It's as mundane and average as can be. It's as mediocre as it can possibly be.

Your claim that the cannot be "proven" to not be in a special position is no different from the claim that no one can prove that there isn't an invisible silent undetectable pink dragon in your basement.

It's an absurd claim. And besides to make the claim that something can't be proven is nonsense. If you want to make a claim you need to make a claim that you can show evidence for.

And all for what? To support an ancient myth that some angry God had his corrupt priests incite the brutal crucifixion of his son so that you could be forgiven of your sins?

I mean, seriously. What rational reasons can you point to that even remotely suggest that the Earth has any special place in the universe as a whole?

I mean obviously it happens to be just the right distance from a stable star to make life possible, but with billions upon billions upon billions of stars in the observable universe it can hardly be considered to be special configuration even in that regard. The fact that some planets would just happen to work out that way is far more reasonable.

And finally, what you are suggesting is not even scientific. Instead of looking at known observed data and then just accepting what the data tells you, you are working backwards with the preconceived bias of wanting the Earth to be special in the hopes of supporting an ancient fairytale.

Why should anyone even bother considering that approach to reasoning? Especially when the fairytale that you are attempting to support is itself extremely unreasonable.

[stcordova]

Current cosmology assumes that the mediocrity principle is true. Our solar system, the earth, and humans are not special. But, is this assumption true? Why or why not?

There are two notions of special that need to be addressed:

1. special in the geometric sense
2. special in the environmental sense

Special in the geometric sense can be established if a few key parts of the Big Bang cosmology is falsified, namely that the universe has no center. If the universe has a center, and all the galaxies are moving away from us, then we are very close to the center of the universe, and hence we live in a privileged geometric position. Astronomer Halton Arp explains that we at least superficially look like were in the center of the universe.

See:
http://www.haltonarp.com/articles/finge ... g_universe


We are special in the environmental sense. Not many locations in the universe, maybe only one location in the universe, is as hospitable for systems as biologically complex as those living creatures on Earth.

For starters, most places are too cold or too hot for ideal solvents (like water) to be in the liquid state. For that matter not many places have water! Not too hot not too cold, but just right -- the Goldilox zone. We apparently live in a Goldilox zone.


So we live in an exceptionally hospitable place with the inter galactic "fingers of God" pointing at us. I'd say it's a good be we're special.

As one of my professor of physics said in his famous book:

“If I were a religious man, I would say that everything we have learned about life in the past 20 years shows that we are unique and therefore special in God's sight.�

James Trefil