Anthropic principle

[Perpetual Student]

The anthropic principal is the insertion of human ego into Science.
Nothing less. Nothing more.


(And, therefore, not something you want your scientific ideas to rely on.)

Not true. Speculation about the anthropic principle have been fruitful in producing interesting cosmological theories and , I suspect, will continue to do so. As sol stated, religion, superstition and anthropocentric musings are irrelevant to the anthropic principle as it relates to physics and cosmology.

 

[Wowbagger]

Not true. Speculation about the anthropic principle have been fruitful in producing interesting cosmological theories and , I suspect, will continue to do so. As sol stated, religion, superstition and anthropocentric musings are irrelevant to the anthropic principle as it relates to physics and cosmology.

So, it's good for sparking the imagination. Fine.

But, in the end, all of those cosmological theories will have to rely on something better (such as, well.... evidence), before they are taken too seriously. See?

 

[SusanB-M1]

All so very interesting. The New Scientist (of 27th September I think) had a very long article on the beginnings and growth of the universe, including how Earth became as it is. I was listening to the audio (CD) although I did not try to retain the info! Not sure if this is a bit off topic, but just thought I'd mention it.

 

[Cuddles]

Sure - but how do you know when you've reached that point?

My whle point was that it doesn't matter if you've reached that point or not, or whether you know it or not. It's an inescapable fact that either there must be a fundamental level or the chain of everything being made of smaller things goes on forever. In either case, science cannot find an ultimate "Why", since any answer simply opens up a new question. I don't think it can be possible to know when you reach the fundamental level, assuming there is one, but I wouldn't bet any money on that.

The anthropic principal is the insertion of human ego into Science.
Nothing less. Nothing more.

Nope. In fact, it's pretty much exact opposite. The anthropic principle doesn't say that the universe is the way it is in order for us to arise, it says that we arose because the universe is the way it is.

This misrepresentation of the anthropic priniple is far too common, and is nicely demonstrated by the puddle analogy. The anthropic principle does not say that a puddle fitting perfectly into a hole is something amazing, the counter to this, that the puddle is that shape because the hole is that shape is the anthropic principle. That's the hole point of it.

When it comes down to it, the anthropic principle is just a way of saying that things are the way they are because otherwise they'd be different. It is just a way of emphasising my point above - there is no ultimate "why", at some point you just have to accept that things are the way they are.

I should probably clarify this a bit. I am not saying that we should ever stop looking for the "why", since even though we may never get an ultimate answer, we can always understand more than we do now. However, we do have to understand that we will never get an answer to Life, the Universe and Everything. That's all the anthropic principle says.

(And, therefore, not something you want your scientific ideas to rely on.)

As far as I know, no-one has ever suggested that we should. The anthropic principle does not pretend to give any answers or provide any basis for them. It is simply a statement that even if we find a fundamental basis for the universe, we will not be able to answer why it is that basis and not another. It's not something scientific ideas rely on, it's simply something to keep at the back of your mind while thinking about them.

 

[Perpetual Student]

So, it's good for sparking the imagination. Fine.

But, in the end, all of those cosmological theories will have to rely on something better (such as, well.... evidence), before they are taken too seriously. See?

See what? Cosmological theories are attempts to extrapolate from current models, that are acknowledged to be incomplete. Evidence is very hard to come by when it comes to the ultimate questions of the nature and origins of the universe. The anthropic principle is an attempt to seek evidence and answers.

As sol already said:
"At some point in human history we understood that not only was the earth not the center of the universe, it wasn't even remotely unique or special - that there are tens of billions of stars in our galaxy alone, which is one tiny mote in a giant sea of galaxies and galaxy clusters. That was a crushing blow to religion, but it is nothing compared to what comes in those models where the AP gains the most traction. In those, not only is the earth not special, the entire observable universe, along with its laws of physics, is but one an a nearly infinite array of possibilities, all embedded in an almost inconceivably large and complex higher dimensional spacetime."

Think about that!

 

[Fredrik]

That agrees with my view of the AP as well. I don't think it's worth much if the observable universe is all there is, but if there are other universes* or other regions of this universe where the laws of physics are different, then the AP actually explains why the laws of physics that we have discovered are fine-tuned for life.

I know that a lot of people say that the laws of physics aren't fine-tuned, but I strongly disagree with that. Change the values of a parameter or two by a small amount and the consequences could be that stable atoms can't form or that stars burn out much too fast to give life a chance to begin.

*) The concept of "other universes" would of course require a definition of "universe" which is different from "all there is".

 

[EGarrett]

I interpreted your subtext to be "the anthropic principle is empty and useless", which irritated me because I think it's false,

I don't think it's empty and useless, but I don't like any suggestion that it's a "spooky coincidence," because it then implies the same logic that suggests that it's a spooky coincidence that we happen to be on the one planet in the solar system that is at the right distance for us to survive.

This isn't to say that we don't try to understand WHY the laws of the universe are the way they are. But I don't like saying it's a coincidence because it suggests that there's not a reasonable solution.

and because I've explained why multiple times in this thread without anyone making any attempt to show why I'm wrong.

Wrong about what? You saying that the anthropic principle means we aren't special? I can challenge that...

Are your parents unique and important to you?

Then why wouldn't our universe and home planet be unique and important to us?

 

[Tubbythin]

I know that a lot of people say that the laws of physics aren't fine-tuned, but I strongly disagree with that. Change the values of a parameter or two by a small amount and the consequences could be that stable atoms can't form or that stars burn out much too fast to give life a chance to begin.

This is what sometimes strikes me as lack of imagination. Change the fundamental constants a bit to create a new Universe.
But why? If its a different Universe why does our new Universe have to have the same constants (but slightly different)? Why can't it have a whole new set of constants. Why can't there be 16 fundamental forces in it and 8 dimensions?

 

[Wowbagger]

All right, so maybe the Anthropic Principal is a bit more than just the application of ego. But, that does not change the argument that should be relied upon. You can't win a scientific debate by appealing to the athropic prinicpal alone. You also evidence, or at least some theory that could work in principal. Or something like that... right?

 

[Perpetual Student]

I think some people are missing a point here. It appears to be well established that many fundamental values and constants are exquisitely “fine tuned” to account for the universe we know. (stars, planets, galaxies, life, etc.)
Superficially, this creates the illusion of design.
A deeper insight, however, is that because it is so unlikely that these constants and values have come together by chance in our universe, we can speculate that this is only one of a huge (or infinite) number of possible universes. In fact, the infinitesimally small likelihood of our specific universe makes it quite compelling that those other universes do, in fact, exist and that ours is merely the one that makes us possible. That is not to say that other universes may not be hospitable to the creation of sentient life, perhaps in some vastly different form. As Fredrik points out the term “universe” needs to be modified or understood in this context.

 

[blobru]

... Nope. In fact, it's pretty much exact opposite. The anthropic principle doesn't say that the universe is the way it is in order for us to arise, it says that we arose because the universe is the way it is. ...

I think the fine-tuning argument (the universe is as it is because of us) is often confused with the anthropic principle (we are as we are because of the universe). Teleological fine-tuning is the anthropocentric sequel to the anthropic principle.

I think some people are missing a point here. It appears to be well established that many fundamental values and constants are exquisitely “fine tuned” to account for the universe we know. (stars, planets, galaxies, life, etc.)
Superficially, this creates the illusion of design.
A deeper insight, however, is that because it is so unlikely that these constants and values have come together by chance in our universe, we can speculate that this is only one of a huge (or infinite) number of possible universes. In fact, the infinitesimally small likelihood of our specific universe makes it quite compelling that those other universes do, in fact, exist and that ours is merely the one that makes us possible. That is not to say that other universes may not be hospitable to the creation of sentient life, perhaps in some vastly different form. As Fredrik points out the term “universe” needs to be modified or understood in this context.

Another possibility is that there are constraints on the constants that arise out of the initial event, that not all values of constants are equally probable: it could be that universes can only occur within a very narrow set of values for constants that tend to complex organic structures like us, that what looks like an impossibly narrow band is in fact the whole range or a large swath of it.

 

[Darat]

I'll believe in it when I win the lottery (preferable a rollover one).

 

[Cuddles]

I don't think it's empty and useless, but I don't like any suggestion that it's a "spooky coincidence,"

It's a good job that's nothing to do with the anthropic principle then.

All right, so maybe the Anthropic Principal is a bit more than just the application of ego. But, that does not change the argument that should be relied upon. You can't win a scientific debate by appealing to the athropic prinicpal alone. You also evidence, or at least some theory that could work in principal. Or something like that... right?

Sure. Can you point to a single case where anyone has ever done that? The anthropic principle is an observation, not a theory or an argument. Things are the way they are because the universe is such that it is possible for them to be as they are. That's it. It's not the sort of thing that you could base an argument on even if you wanted to.

 

[Fredrik]

This is what sometimes strikes me as lack of imagination. Change the fundamental constants a bit to create a new Universe.
But why? If its a different Universe why does our new Universe have to have the same constants (but slightly different)? Why can't it have a whole new set of constants. Why can't there be 16 fundamental forces in it and 8 dimensions?

My comment was about fine-tuning, and my point was that a very small change is sufficient to eliminate all life in the universe.

I definitely didn't mean to suggest that slightly different values of parameters in the standard model is the only way in which the universe could be different.

 

[sol invictus]

Sure. Can you point to a single case where anyone has ever done that? The anthropic principle is an observation, not a theory or an argument. Things are the way they are because the universe is such that it is possible for them to be as they are. That's it. It's not the sort of thing that you could base an argument on even if you wanted to.

False.

Using the anthropic principle, Nobel Laureate Steven Weinberg correctly predicted the order of magnitude of the cosmological constant 10 years before there was any hint of it in the data.

 

[EGarrett]

It's a good job that's nothing to do with the anthropic principle then.

...next time try reading the original post before joining a discussion about it.

I am not one to accept supernatural explanations; nevertheless, the extraordinary combinations of these many values leading to the universe as we know it are a spooky coincidence.

 

[Perpetual Student]

False.

Using the anthropic principle, Nobel Laureate Steven Weinberg correctly predicted the order of magnitude of the cosmological constant 10 years before there was any hint of it in the data.

I would like to know more about how he did that. Can you provide a link or a source of some kind?

 

[Perpetual Student]

This was obviously a poor choice of words to describe my point:

Originally Posted by Perpetual Student, in the OP
I am not one to accept supernatural explanations; nevertheless, the extraordinary combinations of these many values leading to the universe as we know it are a spooky coincidence. Sorry!

See my post #50 for a clearer explanation.

 

[sol invictus]

I would like to know more about how he did that. Can you provide a link or a source of some kind?

http://prola.aps.org/abstract/PRL/v59/i22/p2607_1

 

[Tubbythin]

My comment was about fine-tuning, and my point was that a very small change is sufficient to eliminate all life in the universe.

I definitely didn't mean to suggest that slightly different values of parameters in the standard model is the only way in which the universe could be different.

To be more explicit about what I meant, for the constants to be fine tuned it must be that they could have been something else. Otherwise there is no meaning to saying they are tuned.
Then, if it is possible for them to be something else, you have to assume that that isn't the case somewhere else; that alternative universes don't exist. Otherwise the anthropic principle provides the answer.
Then, and only then, does the fine tuning argument make any sense. But to back it up "you" really need to show that of all the possible sets of constants that describe theoretical universes, only a very tiny fraction of them could harbour intelligent life. But people don't do that. They just pick a single constant in our Universe and change it slightly. And go "ooh look, no more us".