Anthropic Principle

[otseng]

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]

I'll agree that there are so many "unknown unknowns" (to borrow a term from Rumsy), but I think it goes even deeper (or more abstract) than silicone or elements. Beyond the question, 'can life be based on something other than carbon,' is the more fundamental question - which I hinted at in my earlier post - we don't even know what life is! Does 'life' have to equal consumption/excretion? Does life have to have a linear cycle? Do 'living' things have to reproduce? Is life necessarily dependent on the particular state of matter we call 'solid?' The truth is, we don't know the answers to any of these questions, and at the most fundamental level, we cannot therefor assume that life 'is' or 'is not' anything in particular. There is no way to say "we know" that life requires x, y or z.

[veritas]

I'll agree that there are so many "unknown unknowns" (to borrow a term from Rumsy), but I think it goes even deeper (or more abstract) than silicone or elements. Beyond the question, 'can life be based on something other than carbon,' is the more fundamental question - which I hinted at in my earlier post - we don't even know what life is! Does 'life' have to equal consumption/excretion? Does life have to have a linear cycle? Do 'living' things have to reproduce? Is life necessarily dependent on the particular state of matter we call 'solid?' The truth is, we don't know the answers to any of these questions, and at the most fundamental level, we cannot therefor assume that life 'is' or 'is not' anything in particular. There is no way to say "we know" that life requires x, y or z.

That's a good point.

As a long-time reader of Science Fiction, I will admit to a bit of a "romance" to my own ideas of extra-terrestrial life. I'd like for their to be other life forms out there. I'd like them to be friendly. I'd like for them to be, well, basically like the "aliens" we saw in Star Trek--with their own good and evil, but each race familiar enough to relate to, but unfamiliar enough to be "exotic." I know it's not going to happen that way, and that my concept there is nothing more than silliness, but...sometimes I wonder.

Taken in the right view, science fiction and fantasy is a form of metaphor where, traditionally, it's been OK to say "What if..." So these stories--or, at least, the best of the stories--do not actually speak of "aliens" from an alien point of view, but from a human one.

:shrug: What is good in science fiction may, indeed be a limitation in hard science.

Justin

[otseng]

Why is carbon the ideal element to base life on?

Carbon has an amazing characteristic in that it can form a huge number of compounds. Over a quarter of a million different carbon compounds have been identified so far. It is able to do this because of it's covalent and noncovalent bond properties. Carbon is found in hydrocarbons, alcohols, fatty acids, amino acids, et al.

Carbon, along with hydrogen, oxygen, and nitrogen, is among the most abundant of the elements in the universe.

Carbon compounds are also relatively inert, making it a safe for life. They are neither too acidic or too basic.

Carbon compounds are metastable. It is stable enough to last a long time without decomposing. However, when activated by a catalyst, it can release a lot of energy. These qualities also make it ideal for life.

Heat can also alter carbon compounds. And interestingly, they start becoming unstable over 100 degrees C. And since life is based on water, carbon compounds are stable within the temperature range of liquid water.

[otseng]

As a long-time reader of Science Fiction, I will admit to a bit of a "romance" to my own ideas of extra-terrestrial life. I'd like for their to be other life forms out there.

We have certainly been inculcated by science fiction that other forms of life exist out there. Without aliens, science fiction would be kinda boring, as least Star Trek/Star Wars would be quite boring.

How would it affect peoples' thoughts if we knew that we lived in a barren universe? That the only life to exist in our entire universe was here on this planet.

[Angry McFurious]

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. "

Ok we say that it's fine tuned to fit us. But chances are, if it was different, when we started evolving our bodies would have adapted to fit into a differently tuned earth. We wouldn;t evolve into soemthing to not match our surroundings, thats common sence.

[otseng]

The "oldness/flatness" problem of the universe was brought up in another thread, but I want to mention it here also.

The "oldness/flatness" problem involves the "oldness" and "flatness" of the universe and how the Big Bang produced a universe that exists to this point and also has a seemingly Euclidean geometry.

One consequence of general relativity is that the curvature of space depends on the ratio of rho to rho(crit). We call this ratio Omega = rho/rho(crit). For Omega less than 1, the Universe has negatively curved or hyperbolic geometry. For Omega = 1, the Universe has Euclidean or flat geometry. For Omega greater than 1, the Universe has positively curved or spherical geometry. We have already seen that the zero density case has hyperbolic geometry, since the cosmic time slices in the special relativistic coordinates were hyperboloids in this model.

However, if Omegao is sufficiently greater than 1, the Universe will eventually stop expanding, and then Omega will become infinite. If Omegao is less than 1, the Universe will expand forever and the density goes down faster than the critical density so Omega gets smaller and smaller. Thus Omega = 1 is an unstable stationary point unless the expansion of the universe is accelerating, and it is quite remarkable that Omega is anywhere close to 1 now.

So, if the density of the matter after 1 nsec from the Big Bang is equal to 447,225,917,218,507,401,284,017 mg/cc, the Universe would have collapsed by now. And if the density of the matter after 1 nsec from the Big Bang is equal to 447,225,917,218,507,401,284,015 mg/cc, the Universe would not be flat enough for galaxies and stars to form.

Therefore, the margin of error for us to exist is 1 in 447,225,917,218,507,401,284,016.

[Dilettante]

otseng wrote:

Therefore, the margin of error for us to exist is 1 in 447,225,917,218,507,401,284,016.

I suspect that it's inevitable that the universe would seem fine-tuned for us to exist, because the fact is that we exist. If it had been different, we would not exist and we wouldn't be able to claim it's fine-tuned. The reason why the argument from rarity is not very convincing to me is that, if I won the lottery tomorrow, it would probably seem to me that somehow "it was meant to be", since the chances are ridiculously low. However, that is no good reason to believe that I had been predestined to be a lottery winner. I would like to be able to say that the universe had been created for us, but I don't see any strong evidence for it.

[Chem]

So, a certain amount of energy is needed for chemical reactions to occur, yet not too much so that it damages atoms and molecular structures. We find this range to be the visible light and infrared area. And, like mentioned before, this is an extremely small band.

Sorry, but I have to object to the above part of the post. It is not as simple as having light energy to initiate reactions. While energy is required for chemical reactions to occur (light, heat etc. don't forget reactions can occur in the absence of light) the amount of energy can be mitigated by the presence of a catalyst which can reduce the "bump" (activation energy) needed to begin the reaction. In general a catalyst could be a porous dust particle (zeolites would be an example) whereby one of the reactant molecules is adsorbed onto the surface affecting the molecule, altering the charge distribution, making it more susceptable to react.

[Chem]

Carbon has an amazing characteristic in that it can form a huge number of compounds. Over a quarter of a million different carbon compounds have been identified so far. It is able to do this because of it's covalent and noncovalent bond properties. Carbon is found in hydrocarbons, alcohols, fatty acids, amino acids, et al.

The ability of carbon to form so many compounds is due to its ability to catenate- form long chained molecules with itself. This is due to its location in the Periodic Table. Located in the fist series of the table carbon has four electrons in its outer shell and is not affected by "flabiness" noted in elements further down the table (the nucleus having a lesser effect on the valence (reactive) electrons).

Like all elements of this series, carbon obeys the octet rule (eight electrons in the outer shell). The electrons are located in s and p subshells and hybridise to form an sp3 subshell containing 4 unpaired electrons hance its ability to form stable covalent compounds (you get sp2 and sp hybridisation for double and triple bonds). Of course the shells referd to are a misnomer and are actually the areas where the electrons are most likely to be found. Each of the subshells contain a maximum of two electrons of opposite spin (a quantum property) according to Paulings exclusion principle.

Who ever said chemistry was boring?

I certainly do not see anything divine in the chemistry of carbon.

[Jose]

Isn't the Anthropic Principle sort of silly? It says no more than the basic observation that we are composed of the atoms that are in our universe. As far as we know, the vast majority of the universe is quite hostile to humans, and to life in general. But obviously, if life were to arise on any planet, it would have the characteristics that make it work on that planet. To say that this indicates that the planet was designed for that life form is unwarranted. Why not say that most of the universe was designed to be hostile to life, but that the earth was a mistake? This view is just as likely--and the two ideas can never be distinguished.