Norm Weatherby left some comments in my previous post on this subject. Since he doesn't have comments turned on, I'll respond here.
Read this then click on the "Whole Story" link to possess the finest explanation of this concept I think has ever been made.
The link appears not to be working right now. I'll try again later.
The sheer magnitude and formadibility of scientific reputation and credentials of those featured in what you are about to read makes casual or brief dismissal of their conclusions problamatic.
Um... unfortunately, science isn't subject to a vote, and even the most prestigious of them can get it wrong. Indeed, Stephen Hawking recently conceded a bet he had made on the "black hole information problem". Information, he now believes, does not disappear from the universe beyond the event horizon of a black hole – it leaks back out, albeit mangled.
And just to throw another irony in the fire, he could still be wrong.
Dr. Dennis Scania... "If you change a little bit the laws of nature, or you change a little bit the constants of nature ... then the way the universe develops is so changed, it is very likely that intelligent life would not have been able to develop." Dr. David D. Deutsch: "If we nudge one of these constants just a few percent... Dr. Paul Davies, : "The really amazing thing is not that life on Earth is balanced on a knife-edge, but that the entire universe is balanced on a knife-edge, and would be total chaos if any of the natural 'constants' were off even slightly...
OK, so they said those things. Are there no voices on the other side?
Well, funny you should ask...
The article linked above is one voice on the other side, by a physicist and astronomy professor at the University of Hawaii. Granted, not the most prestigious credentials in the world, but again, credentials don't determine who's right – who's right determines credentials, and even the most highly credentialed can go off. There are any number of examples of great minds that have wandered off into goofball theories later in life.
So, what do we have in the way of data?
The arguments above are arguments from probability. How sound an argument is this?
If we properly compute, according to statistical theory, the probability for the universe existing with the properties it has, the result is unity! The universe exists with one hundred percent probability (unless you are an idealist who believes everything exists only in your own mind).
In other words, the probability of something that already exists is 100%
On the other hand, the probability for one of a random set of universes being our particular universe is a different question. And the probability that one of a random set of universes is a universe that supports some form of life is a third question. I submit it is this last question that is the important one and that we have no reason to be sure that this probability is small.
"...no reason to be sure that this probability is small." Somehow, that detail never seems to make it into the ID/IOT arguments.
I have made some estimates of the probability that a chance distribution of physical constants can produce a universe with properties sufficient that some form of life would have likely had sufficient time to evolve. In this study, I randomly varied the constants of physics (I assume the same laws of physics as exist in our universe, since I know no other) over a range of ten orders of magnitude around their existing values. For each resulting "toy" universe, I computed various quantities such as the size of atoms and the lifetimes of stars. I found that almost all combinations of physical constants lead to universes, albeit strange ones, that would live long enough for some type of complexity to form (Stenger 1995: chapter 8). Figure 1. Distribution of stellar lifetimes for 100 random universes in which four basic physics constants (the proton and electron masses and the strengths of the electromagnetic and strong forces) are varied by ten orders of magnitude around their existing values in our universe. Otherwise, the laws of physics are unchanged. Note that in well over half the universes, stars live at least a billion years. From Stenger 1995.
"In well over half the universes, stars live at least a billion years." Remember, these are universes where the critical fundamental constants referred to by the luminaries quoted above are allowed to vary around the values in our universe by ten orders of magnitude. That's a range of ten billion times from the high end to the low end.
The rest of the article deals with other popular topics in the physics of evolution. Those who are interested in learning the merits of the argument are advised to read the whole thing.
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