There are many things about the earth that are just right for humanity to survive here. We are the right distance from the sun, there is the right amount of water on the planet, there's even jupiter in the solar system which seems to help reduce the number of asteroid impacts that we have to deal with. I'm sure there are many other things about our planet that are set up just perfect for life. This is interesting and cool, but does it point to God?
Let's suppose that we have this laundry list of conditions that have to be just right for life to exist on our planet. Let's also suppose that the odds of any given star randomly ending up with all of these conditions is about 1 in a billion (I have no idea how we could determine odds like this, but the real point is just that it is incredibly unlikely). If there are also a billion stars out there, maybe the fact that this 1 in a billion coincidence happened somewhere isn't quite so amazing anymore.
So how many stars are really out there? According to wikipedia, our galaxy has somewhere between 200-400 billion stars. But that is just one galaxy out of many, if you go to http://hubblesite.org, you can see many pictures like the one below which shows a huge number of galaxies, each with a huge number of stars within.
If each star represents a chance for intelligent life to evolve, the fact that it happened somewhere is actually not terribly remarkable. And wherever it happens is the only place where those intelligent beings are going to be able to look at their surroundings and say "wow, it's amazing that all of these unlikely things have happened here that allow us to exist!" But if they only consider their own solar system, if they don't consider the trillions of other stars that (as far as they know) don't have intelligent life, then they are really cherry picking the data.
Usually people making that argument are creationists.
ReplyDeleteThey that the "ideal" conditions for life on Earth are a sign that god created this world "just for us"
Sheldon: I'd have to also agree. When you use the term "fine tuned" that begs the question of a divine creator. Maybe I'm being picky, but I think a more fair way to pose a question like that is "Is our universe fine tuned OR (as you stated) were the conditions just right for it to happen?"
DeleteHausdorff: You probably are familiar with the Drake equation. http://en.wikipedia.org/wiki/Drake_equation This might be a good reference for future arguments.
Yeah, that is definitely the idea they are trying to push forward. I would argue that with all the stars in the sky they are just being shortsighted.
DeleteAnd yeah, the drake equation is pretty cool. The numbers we stick into those variables are obviously pretty wild guesses, but it is neat to think that we can refine them over the years and get better estimates as time goes on.
Sometimes the argument that the earth is fine tuned for life is couched in probabilities, the gist of which is that it is so improbable the earth would be "just so" that there must be some intelligence that designed it so. Of course, the probability of something happening that has already happened once is 1. Consequently, the argument falls apart due to its ignorance of mathematics.
ReplyDeleteyeah, those probability arguments always bug me a little bit, because the odds that they come up with usually have no real basis in reality. The great thing about arguing against the fine tuning of the earth, even if they try to say that the odds against the earth being perfect for life are astronomical, we can grant them that assumption and still win based on the number of stars/planets out there. If the odds of any given star producing life is 1 in 200 billion, since there are over 200 billion stars in our galaxy it is not so remarkable that it happened somewhere. And given that there are countless galaxies out there at some point it just becomes inevitable that it will happen somewhere.
DeleteI just heard something the other day that ties into this for consideration:
ReplyDeleteThere are more stars in the universe than there are grains of sand on the earth.
Chance is a wonderful thing! :-)
I like that, I like it a lot :)
DeleteI wonder how someone would go about figuring out how many grains of sand there are on the earth.
My guess is volumetric estimation, but it could have been done in reverse. In other words, we know approximately how many stars there are and what the average size grain of sand is. Multiply the two, and if the result would cover the earth ten feet deep, then you know there are more stars. :-)
DeleteI got that info from some sort of consolidated random fact blurb, but there were no noted sources. :-(
volume estimation sounds like a reasonable guess for how they would do it
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