Posted by aogThursday, 07 May 2009 at 17:01
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What I thought of when I read that cosmology was in crisis again (via Brothers Judd) was how Anthropogenic Global Warming is “settled science”, but Newton’s Theory of Gravitation is not.
|Annoying Old Guy
Friday, 08 May 2009 at 10:53|
I don’t know, I wasn’t the one who kept bringing up Darwin. And it’s closer to 8 billion years before terrestial biology shows up according to current cosmological timelines.
Technically, the multiverse theory isn’t scientifically sound, because it’s not capable of being proved or disproved. I will admit that I have visceral dislike for the theory because it eliminates moral agency. If everything that can happen will happen, it means that you will make all possible decisions, which is really not making any decision. I.e., there are other realities where I am a hard core New Dealer and Mr. Eagar is a rapid free market and we argue about that on his weblog. If so, where is our ability to choose? On the other hand, it solves the free will problem by writing it out of the structure of reality.
I am not sure the widespread antipathy to divine / supernatural explanations is contrary to scientific rigor. After all, what is supernatural but a label for “not scientific”? If scientific rigor means be strict about being scientific, then such antipathy is required. You may, as OJ does, object to Science as a whole on that basis, but I think that objecting to science trying to be scientific is silly1.
I do think that a lot of layman who think they know about cosmology and the “Big Bang” don’t have any clue as to how ad hoc so much of that is. The people who do know sound like they’re sure but that’s just academic posturing. If you look closely, however, you can see that most of the community is quite aware of that. It’s one of the reasons that so much effort was poured in to String Theory, because it held the hope of removing all that ad hocness. A sign of desperation, not strength.
I do think the multiverse theory is legerdemain, but not so much to avoid implications of the Anthropic Principle. That’s just a happy coicidence. Avoiding having to explain what it means for a quantum wave function to collapse, that’s the real goal. You can see that if you trace the history of the concept back to its source. It’s one of the things that is very attractive to me about Penrose’s view.
1 It’s just like the Archbishop of Canterbury objecting to the invasion of Iraq on moral grounds, using the UN as the source of that morality without mention of Jesus Christ. That may be reasonable position to take, but it’s hardly a Christian one. I utterly despise people who use theologies and ideologies as marketing labels without meaning. Gah! Sorry, pet peeve.
Friday, 08 May 2009 at 14:06|
I’d like to recommend Martin Rees’ “Six Numbers”, and the Anthropic Principle and the fine tuning of our universe’s physical characteristics it describes. Rees basically says that there are three responses to the statistically unlikely nature of the fine tuning and the incredible sensitivity of these values to the chance of matter or life forming:
A. Shrug of the shoulders, its trivial (implied by the weak anthropic principle)
B. Evidence of a Cosmic Design (implied by the strong anthropic principle)
C. There is an infinite number of parallel universes only a tiny fraction of which have, purely by chance, been created with the right physical constants to allow matter to form and life to develop. We just happen to be lucky enough to be in one that does (Many World theorem).
Parallel universes, Option #3, by definition can never be observed or visited and will forever remain non-falsifiable and therfore meaningless under the strict rules of Logical positivism as defined by Popper. As such, it is an explanation equivalent to “evidence for divine design”. If a “parallel” universe could be visited or observed, it wouldn’t be a separate universe at all but a different region of the same space-time. From the point of view of being non-falsifiable, “God” and “parallel universes” are equally valid explanations (even Schermer admitted as much in “Why We Believe”).
Furthermore, multiple universes cannot in themselves provide an explanation for the fine tuning of the forces (those “Six Numbers” rees talks about) that make life in this universe possible. When the universe splits with each “quantum decision” made by an elementary particle both new universes are virtually identical to each other except for this single quantum difference that caused the split, all other attributes would be the same. As such, they would share the same physical laws, constants, etc. The quantum multiplication of universes would not result in changes in physical properties.
Lastly, the many worlds hypothesis is is not “elegant”, as most successful physical theories are. Its a crude blunderbuss approach requiring a near infinity of universes to explain a few basic forces and characteristics, epistemological over kill. God is a much simpler explanation. Oddly enough, in this case, Occam’s Razor works in God’s favor.
Going back to Option #1, The Weak Anthropic Principle (WAP) basicly says “We are here because we are here.” It’s a tautology which solves nothing and provides no answers. If I am facing a firing squad and all 21 guns misfire (against astronomical odds) I have every right to wonder why. My amazement at being alive would be justified. To not wonder at my good fortune would show a lack of curiosity bordering on the bovine. Which violates at least the spirit of scientific inquirery.
By default,that leaves us with Option #2, God did it. In fact, the only way to deny Option #2 is by relying on the UN-scientific options: the non-falsifiability of parallel universes or the tautology of weak explanation.
Saturday, 09 May 2009 at 15:55|
Perhaps statistically isn’t the right word, but isn’t the problem the cumulative nature of it all?
The probability assumption still underlies your question. Since we have exactly one data point to work with, for all we know, the problem would be if the universe did not turn out this way. (I’ll risk a metaphor: the statistical likelihood of a river assuming a specific path is extremely low, so low that no two rivers are the same. The problem is not with their shape — that is what rivers do. Now, if there was to be a river straight as an arrow; well, that would be a problem. Maybe our universe is the way it is because that is what universes irrevocably do.)
Yes, it is astonishing that all the universe’s constants line up just right so the universe attains sufficient size, in the right amount of time, with stars surviving long enough but not too long, for life to exist in at least one place.
But with only one data point to go on, whether this is a problem that needs explaining, or is in any way improbable, is to conclude from incredulity.
Hoyle’s metaphor is really Paley’s design argument more colorfully stated. Intuitively appealing, but wrong.
Somewhat OT, I can’t help but remark on OJ’s tag line:
One of the things that Darwinists fundamentally misconstrue is that just because you don’t believe in the validity of a theory doesn’t mean you reject the facts it’s trying to describe. You can accept that life forms have evolved and that stones don’t fall upwards while scoffing at the fables scientists use to explain the phenomena.
So, he accepts evolution is true, but dislikes speculative just-so stories?
Tuesday, 12 May 2009 at 17:06|
Peter, if Lubos Motl is right, you were wasting your time with Smolin. I haven’t read him. My physics adviser (not a particle physicist, rocket scientist) recommends Brian Greene.
For a strict materialist, the Universe is an axiom. The question cannot be answered because it should not be asked.
A milder form would be to say that, this isn’t ‘science,’ it is the framing of scientific hypotheses too early in the investigation process.
I have a homelier example that, if I had time, could be developed into a book: Consider the family trees constructed of fossil primates.
When there were just 2 (us and Neandertal), the tree was a stick. It became harder and harder to make the tree coherent as more branches were ‘discovered,’ until it was realized that some of the branches belonged to a different bush and didn’t have to be fitted into the puzzle. (The exclusion of Zinjanthropus from the direct line of descent, for example.)
Speculation is fun and occupies time that could be better spent gardening, but just because it is about topics that would be of interest to the scientifically minded, that doesn’t make it science. Yet.
So how do I, as a strict materialist, get around Guy’s conundrum of the collapse of the Schroedinger wave function? Well, if science is what can be observably examined, then I simply dismiss the correlation of particles beyond some (very small) distance. It is all very well to extend the logic of particle interactions to say that, in principle, two particles simultaneously created could separate themselves by the radius of the universe,and when one is collapsed, the other knows what to collapse to.
But in the real universe (what, as Skipper says, universes do), particles do not separate themselves by the radius of the universe before either one has its wave function collapsed (so far as we can observe).
We might very much like to observe things, but that doesn’t mean we have to.
It makes a difference whether a particle is obliged to collapse its function, no?