Anthropic Principle

Post by **otseng** » Tue Apr 20, 2004 12:56 pm

This topic is an offshoot from Does God exist or not? Since this topic is a huge area of debate, I'm making this have it's own thread.

So, the question of debate is...
Does the Anthropic Principle point to the existence of God?

First, let's give some definitions of the Anthropic Principle (AP).

Wikipedia:
"Any valid theory of the universe must be consistent with our existence as carbon-based human beings at this particular time and place in the universe."

Philosophy Pages:
"Belief that the existence of human life entails certain features of the physical world. In a minimal form, this view merely points out that we would not be here to observe natural phenomena were they not compatible with our existence. Stronger versions of the anthropic principle, however, seem to rely upon the idealistic notion that the universe could not exist without intelligent observers."

Augustine Fellowship:
"The observation that the universe has all the necessary and narrowly-defined characteristics to make man and his sustained existence possible. The view that the universe is conspicuously 'fine-tuned' for human existence. "

Quarkhead · Post by **Quarkhead** » Fri Apr 30, 2004 11:54 am

I'll chime in with perspective on this one. Otseng, I think you are missing a crucial part of the Anthropic principle, on a more metaphysical level. It is your assumptions about what constitutes life, which is more curtailed by the selection effect than anything else. I do not doubt that you are right, insofar as carbon-based life is concerned; but the fact is that we only have definitions for life which reflect our own. Now, as we see more strange occurences of "life" in the deepest parts of the ocean, perhaps our definitions of life itself can be broadened - but only so much, because we don't really know what life is or means.

Turthfully, we can only come to a (limited) conclusion that life as we know it may be quite rare in the universe. Of course we must recognize at the same time that our definition of life itself is limited by the anthropic principle.

But, even if life does only exist on one planet in the universe, that doesn't necessarily lead to a belief in the existence of a creator. Here, the argument comes down to, well it's so improbable for life to have come into existence, that there simply must be a god. Of course, just because something is highly coincidental does not serve as evidence that it must not be coincidental at all.

Post by **otseng** » Fri Apr 30, 2004 3:18 pm

Quarkhead wrote:I'll chime in with perspective on this one. Otseng, I think you are missing a crucial part of the Anthropic principle, on a more metaphysical level. It is your assumptions about what constitutes life, which is more curtailed by the selection effect than anything else.

There could be the probability of other forms of life that doesn't depend on stars as an energy source, that is not dependent on water and oxygen, and is silicon based. But we have no basis to support this, neither from empirical evidence nor knowledge of the sciences. The best that can be concluded is that if there are other life forms different from ours, we have no idea of their makeup.

Of course we must recognize at the same time that our definition of life itself is limited by the anthropic principle.

I would rather state it that our definition of life is limited by our knowledge of the sciences, rather then the anthropic principle.

Here, the argument comes down to, well it's so improbable for life to have come into existence, that there simply must be a god. Of course, just because something is highly coincidental does not serve as evidence that it must not be coincidental at all.

Sure, there exists that finite chance that it all occurred purely by luck. But the odds are so remote that hanging anything on such odds is highly risky.

perspective · Post by **perspective** » Mon May 03, 2004 8:05 am

otseng wrote:
Here, the argument comes down to, well it's so improbable for life to have come into existence, that there simply must be a god. Of course, just because something is highly coincidental does not serve as evidence that it must not be coincidental at all.
Sure, there exists that finite chance that it all occurred purely by luck. But the odds are so remote that hanging anything on such odds is highly risky.

The sentence: "But the odds are so remote that hanging anything on such odds is highly risky." is the fallacy we're debating. You have no way to know that the odds are remote. You're observation is biased by the selection effect that is inherent in the anthropic principle.

Post by **otseng** » Mon May 03, 2004 8:52 am

perspective wrote: The sentence: "But the odds are so remote that hanging anything on such odds is highly risky." is the fallacy we're debating. You have no way to know that the odds are remote. You're observation is biased by the selection effect that is inherent in the anthropic principle.

When you say selection effect, there is an implication that there are other alternatives for the basis of life. If there is only 1 choice, it's not much of a selection effect. To say that the selection effect is a factor requires that alternative possibilities be viable. Evidence will need to be given that there are other things to select from. If no such evidence can be given, then the argument of the selection effect is moot.

perspective · Post by **perspective** » Mon May 03, 2004 9:24 am

otseng wrote:
perspective wrote: The sentence: "But the odds are so remote that hanging anything on such odds is highly risky." is the fallacy we're debating. You have no way to know that the odds are remote. You're observation is biased by the selection effect that is inherent in the anthropic principle.
When you say selection effect, there is an implication that there are other alternatives for the basis of life. If there is only 1 choice, it's not much of a selection effect. To say that the selection effect is a factor requires that alternative possibilities be viable. Evidence will need to be given that there are other things to select from. If no such evidence can be given, then the argument of the selection effect is moot.

The selection effect results from the set of the whole that you are using to compute odds. You can't compute odds because you have no way to know which set you are using to compute the odds. Saying, "the odds of life happening, based on what we know" is like saying "the odds that this country frowns on divorce, based on my asking all my conservative friends". We know that your conservative friends are not all that exist in the country. We know that "what we know" about the universe isn't all that exist. Stating "odds" or statistics of the whole based on a partial set of the whole is a selection effect.

trei · Post by **trei** » Mon May 03, 2004 10:43 am

If we look at those three original statements of the Anthropic Principle, none of them refer to "life" in the general sense of all possible forms of life, imaginable or unimaginable, according to whatever definition of life we settle on, in our universe.

They refer to human life or human-ish life, carbon-based life.
I think what the Anthropic Principle is getting at is that there is an absolutely minute chance that we - or other organisms sufficiently akin to us - should occur in our universe.

As for there being no way to put numbers to this claim of 'miniscule', of course we cannot give this probability with absolute certainly to the twentieth significant figure. Because, as has been said, the information we have about the universe is very limited.

But considering the matter using the information we have and making some assumptions, we do come out with a miniscule figure. And I must say that I don't find it entirely unreasonable - say we look at the stars in our galaxy, and consider the few that would be able to support *human life, carbon-based life*, I think we could use this information to determine a final probability. It wouldn't be unreasonable to do so.

perspective · Post by **perspective** » Mon May 03, 2004 1:38 pm

trei wrote: But considering the matter using the information we have and making some assumptions, we do come out with a miniscule figure. And I must say that I don't find it entirely unreasonable - say we look at the stars in our galaxy, and consider the few that would be able to support *human life, carbon-based life*, I think we could use this information to determine a final probability. It wouldn't be unreasonable to do so.

But this is exactly what many experts agree - we cannot claim that something seems unlikely:

From a dissection on Barrow & Tipler's dissertation of the Anthropic Principle

We should emphasize once again that the enormous improbability of the evolution of intelligent life in general and Homo sapiens in particular does not mean we should be amazed we exist at all. This would make as much sense as Elizabeth II being amazed she is Queen of England. Even though the probability of a given Briton being monarch is about 10-8, someone must be. Only if there is a monarch is it possible for the monarch to calculate the improbability of her particular existence. Similarly, only if an intelligent species does evolve is it possible for its members to ask how probable it is for an intelligent species to evolve. Both are examples of WAP self-selection in action.110

According to the Anthropic Philosophy, an attitude of surprise at the delicately balanced features of the universe essential to life is inappropriate; we should expect the universe to look this way. While this does not explain the origin of those features, it shows that no explanation is necesary. Hence, to posit a divine Designer is gratuitous.

This article breaks down the theories into probability formulae. It's a bit dry reading, but it goes down the actual logical arguments why likelihood not only doesn't point towards divine creation, but actually supports the opposite.
This article too.

trei · Post by **trei** » Tue May 04, 2004 6:40 am

Dry - you weren't joking!
I waded my way through the first bit and I see that you're right - the fact that the universe if not life friendly does not necessarily imply the universe is not governed solely by naturalistic law.

But I'm doubting that the fine-tuning of the universe can "undermine the hypothesis of a supernatural origin of the universe". I will work through the rest later, and then I'll see... I'm expecting that conclusion comes out of the dubious claim that:

it should be noted that a sufficiently powerful supernatural principle or entity (deity) could sustain life in a universe with laws that are not "life-friendly," simply by virtue of that entity's will and power.

But we shall see when I have finished reading it!

Post by **otseng** » Tue May 04, 2004 3:47 pm

perspective wrote:Saying, "the odds of life happening, based on what we know" is like saying "the odds that this country frowns on divorce, based on my asking all my conservative friends". We know that your conservative friends are not all that exist in the country. We know that "what we know" about the universe isn't all that exist. Stating "odds" or statistics of the whole based on a partial set of the whole is a selection effect.

What if suppose that all the citizens in the country were in fact conservative? Sampling a small sample would make no difference than sampling everyone. It might seem inconceivable that everyone in a country would be conservative. But the only way to prove that is not true is to find someone who is not a conservative (which is quite easy to prove in the US). But, until a liberal or moderate is found, how can one say the selection effect is a possibility?

It is true our concept of life is limited to what we see on earth. But the selection effect has a presupposition that there has got to be other life on other planets and it's different from ours. But, there is no evidence of this. It is only a guess. Therefore, the selection effect is just a guess, not a supportable hypothesis.

perspective · Post by **perspective** » Tue May 04, 2004 4:12 pm

otseng wrote: It is true our concept of life is limited to what we see on earth. But the selection effect has a presupposition that there has got to be other life on other planets and it's different from ours. But, there is no evidence of this. It is only a guess. Therefore, the selection effect is just a guess, not a supportable hypothesis.

There is no presupposition that there has got to be other life on other planets that is different than ours. To use the Anthropic Principle to state that this planet is "fine tuned" uses a presupposition that there surely IS NOT other life on other planets that is different than life here. I'm not the one drawing conclusions from incomplete evidence - thus my non-conclusion cannot suffer from a selection effect. Only the drawn conclusions can suffer from a selection effect. Those who try to offer the Anthropic Principle to support a conclusion are the ones in error. Those who point out the error are not the ones making the inaccurate claims to being with. You're trying to use circular logic to confuse the issue.