The Grand Design

[hackenslash]

It would be interesting if a natural extension of Galileo's balls down ramps, the double slit experiment and Feynman's sum over histories explanation of it, now led to the most convincing answer yet to the question of why there is a universe at all.

Not going to happen, and I'm sorry to be pedantic, but the reason it isn't going to happen is that, in science, 'why' is an invalid question. Science only deals in 'how' questions.

Now, usually when I say this, I am met with stiff opposition, so let me pre-empt it here. When a scientist says 'why did that happen?', what he's actually asking is 'what is the mechanism that caused that?', which is not a 'why' question, but a 'how' question. 'Why', implies purpose, which is not a valid assumption in science. Science only deals with mechanisms, which are all 'how' questions.

[hackenslash]

Incidentally, The Grand Design is going to have to wait for now, as I just started On The Shoulders Of Giants which, I suspect, is going to occupy me for at least a couple of weeks, given how little time I have at the moment.

[ablprop]

More opposition. I refuse to cede the why questions. The why questions really are how questions. I find the current explanation for the fine-tuning to be much more satisfying than the old "that's just the way it is" answer. I think we're close to knowing "why" there is something rather than nothing. Of course, there will always be another, "but why should that mechanism exist", but each step leaves me more satisfied than before.

[hackenslash]

More opposition. I refuse to cede the why questions.

Then you aren't likely to get any answers. There's no good reason to suppose that there even is a why.

The why questions really are how questions.

Precisely my point, which is why they aren't why questions.
 

I find the current explanation for the fine-tuning to be much more satisfying than the old "that's just the way it is" answer.

What explanation? More importantly, though, what fine-tuning?

I think we're close to knowing "why" there is something rather than nothing.

Not remotely, but we already know how, namely by the uncertainty principle, which doesn't allow 'nothing', and means that there has to be something.

Of course, there will always be another, "but why should that mechanism exist", but each step leaves me more satisfied than before.

This highlights the problem beautifully. It's like when a two-year-old asks 'why?', and to every response you just get anther 'why?'. In reality, aside from the fact that these questions can't actually be supposed to have answers, they are also the surest and quickest route to infinite regress.

Ultimately, this isn't about ceding the 'why' questions, it's about them having zero utility in terms of elucidating reality.

[ablprop]

A hairdresser once asked me "why are there butterflies?" One answer is, there are butterflies because there are stars. Tracing the path of carbon from the triple alpha process in stars through the origin and subsequent evolution of life gives one very satisfying answer to the question, even if it doesn't get at the hairdresser's probable initial desire for a "purpose" answer. That's what I mean when I say don't cede the why questions. They are where many people start.

[hackenslash]

Yet all those answers are answers to how questions, not why questions. You can refuse to cede the why questions, but what you are actually doing is engaging in a fallacy of equivocation, because why questions are a qualitatively different thing to how questions, and science isn't equipped to deal with them. Nor is religion, for that matter, although it certainly asserts answers.

In short, I'm not talking about ceding the why questions, I'm talking about recognising them as invalid and without utility.

[ablprop]

But people still ask them. I'm interested in taking humans' natural inclination to ask "why" and show how scientific answers can actually satisfy that curiosity in a fulfilling way. I can't give a purpose answer to "why are there butterflies" because there is no purpose answer, but by walking down the "how" path, I can show that those answers can be ultimately quite satisfying and enriching.

When someone who wants purpose asks, "why is there something rather than nothing?" I can give your answer, that the uncertainty principle won't allow a nothing. Now we can discuss the uncertainty principle, how we humans came to understand it, its various applications to things like the monochromicity of laser beams, and so on. Maybe I didn't get at the original desire for a purpose (because, as far as I can tell, there isn't one), but I did, just maybe, provide a fulfilling substitute. It's fulfilling for me, anyway.

[hackenslash]

Ah, but if you're not addressing purpose, then you aren't addressing why questions. Simple as that. That's entirely my point.

[ablprop]

OK. While I have your attention, I was reading about the Pauli Exclusion Principle in my quantum physics text from college. The authors make a point about a certain kind of fine-tuning. Without the PEP, there would be no chemistry because all electrons would fall to the ground state of atoms and behave like noble gases. Now I am far from an understanding of why the exclusion principle arises for particles with half-integral spin (the text references "deep quantum mechanics", whatever that is), but I wonder if we might state that such a principle is an example of the sort of law that has to exist in order for us to exist (and therefore ask the question)? It caught my attention given our discussion about Hawking's book and whether or not fine-tuning even exists.

[Tank]

OK. While I have your attention, I was reading about the Pauli Exclusion Principle in my quantum physics text from college. The authors make a point about a certain kind of fine-tuning. Without the PEP, there would be no chemistry because all electrons would fall to the ground state of atoms and behave like noble gases. Now I am far from an understanding of why the exclusion principle arises for particles with half-integral spin (the text references "deep quantum mechanics", whatever that is), but I wonder if we might state that such a principle is an example of the sort of law that has to exist in order for us to exist (and therefore ask the question)? It caught my attention given our discussion about Hawking's book and whether or not fine-tuning even exists.

Fine tuning implies a Tuner? As in Intelligent Design requires a Designer. But the strong anthropic principle does not require fine tuning but what one might term 'fine slicing' and the PEP 'works' in our particular slice of reality. In the vast majority of multiple reality scenarios the PEP is not within the bounds where it 'works'. Thus we are only here to work out that the PEP needs to be within particular bounds because it is within those bounds. The same would be the case for all the properties that need to be within particular bounds for our universe to be suitably 'tuned' for our existance so we can measure them.

[hackenslash]

^^ Exactly right. This isn't fine-tuning of the universe for life, it's fine-tuning of life for the universe, and the fine-tuning is all done by dint of it having arisen under these conditions.

When scientists talk about fine-tuning, BTW, they are talking about the fine-tuning of models, not the universe. In other words, certain parameters have to fall within a certain narrow band of values if their models are correct. It's all-too east to view this from the wrong perspective, and to think that it means that the universe has been somehow tweaked to fit these values. A clear example is the horizon problem, in which the inflation of the early cosmos has to fit a certain rate in order to explain the isotropy of the cosmos that we measure today. The reality is that there is no good reason to suppose that any of the values of our constants could actually have any other value. The only reason for exploring other values is that thought experiments are very useful in understanding the make-up of the cosmos.

Most importantly, if the last century has taught us anything, it's that our understanding of what constitutes the conditions for life is very narrow. It may be that changing the value of some of the constants actually makes life more probable. Indeed, there is at least one constant, in the form of one of the four fundamental forces, that could be completely removed and it would mean that even life as we know it would be more probable. Remove the weak nuclear force, and suddenly more stable isotopes of carbon are available, which means that more different carbon chains can be built, making life more likely.

http://link.aps.org/doi/10.1103/PhysRevD.74.035006

[ablprop]

Fine tuning implies a Tuner?

Not remotely, and I regret if anything I wrote suggested such an idea. I'm in Dawkins' camp, convinced that the idea of a designer only adds complexity and doesn't solve anything. But I do feel that the possibly arbitrary conditions that allow our existence cry out for at least an attempt at explanation. Read on!

[ablprop]

When scientists talk about fine-tuning, BTW, they are talking about the fine-tuning of models, not the universe.

I don't understand this distinction, and I've not encountered it (or at least not recognized it) in my other reading. I think there's a deep question here that cries out for an answer one way or another. For instance, at a public lecture I once asked Brian Greene why (ok, I should have said "what's the mechanism for") there are exactly three large space dimensions. What causes the other dimensions, if they exist, to be curled up? Or alternatively, why aren't they all curled up? Greene admitted that no one really knows, though he does suggest some intriguing answers in the final part of The Elegant Universe.

Hawking suggests another alternative. If the existence we know is just one of many, then it could be that the number of large vs. small dimensions is a matter of accident. Planetary orbits would be unstable in dimensions with more or less than three large dimensions, so it is no surprise that we find ourselves in a three-dimensional universe.

I'm not convinced of Hawking's multiverse hypothesis, but I think it is an important question to answer. If he's right, than anyone looking for a deep reason for three big dimensions is wasting her time. There is no deep reason, it's just contingent.

So how is this particular fine-tuning, that there are three large space dimensions and not more or less, part of a model and not of the universe?

[Tank]

Fine tuning implies a Tuner?

Not remotely, and I regret if anything I wrote suggested such an idea. I'm in Dawkins' camp, convinced that the idea of a designer only adds complexity and doesn't solve anything. But I do feel that the possibly arbitrary conditions that allow our existence cry out for at least an attempt at explanation. Read on!

Sorry, my wording did possibly intimate that I was implying that you were putting forward an argument for a 'Tuner', which was not my intention!

[hackenslash]

I don't understand this distinction,

It's a fairly straightforward distinction. In the models we construct of what we think are the operational paramaters of the cosmos, there are certain parameters that have to fall within a certain narrow range of values if the models are correct. In other words, it could be that those parameters fall outside that range of values, in which case the model is falsified. For example, in the standard inflationary model, inflation has to proceed at a given rate in order to overcome the horizon problem, which is a problem to do with transmission of information (temperature, in this case) without breaching limitations to c, which it must do in order for the inflationary model to overcome the observed isotropy of the cosmos. It could be that the inflation of the cosmos progressed at a rate outside that range of values, in which case the model is wrong, and we have to think again. This doesn't cause any problems for the cosmos, of course, because the cosmos exists, and exists with constants that allow for life, and has the observed isotropy. In short, it's only a problem for the model. This is what cosmologists are talking about when they talk about fine-tuning. They are not suggesting that the cosmos is fine-tuned.

and I've not encountered it (or at least not recognized it) in my other reading.

You wouldn't necessarily come across it, because fine-tuning arguments only come up in dishonest creationist screeds, and cosmologists don't have much to do with them. Indeed, cosmologists employ a fair bit of language that is open to equivocation because, unlike evolutionary biologists, they aren't used to being confronted by fuckwitted cretinists.

I think there's a deep question here that cries out for an answer one way or another. For instance, at a public lecture I once asked Brian Greene why (ok, I should have said "what's the mechanism for") there are exactly three large space dimensions. What causes the other dimensions, if they exist, to be curled up? Or alternatively, why aren't they all curled up? Greene admitted that no one really knows, though he does suggest some intriguing answers in the final part of The Elegant Universe.

None of that suggests any kind of fine-tuning, and indeed this question is quite nicely covered by the anthropic principle. If there were more or less extended dimensions, we wouldn't be here to ask the question. The reality, though, is that our understanding of the dimensional manifold is in its infancy, and we don't know nearly as much as we'd like. It may be that there are other extended spatial dimensions, separated from ours by additional, Planck-scale spatial dimensions that are so small we can't perceive them. In fact, that is the basis, loosely speaking, for the Turok/Steinhardt 'brane-worlds' model for cosmic instantiation.

Hawking suggests another alternative. If the existence we know is just one of many, then it could be that the number of large vs. small dimensions is a matter of accident. Planetary orbits would be unstable in dimensions with more or less than three large dimensions, so it is no surprise that we find ourselves in a three-dimensional universe.

Bingo. There's the anthropic principle again. This is not original to Hawking, though. Such proposals have been around for a very long time.

I'm not convinced of Hawking's multiverse hypothesis, but I think it is an important question to answer.

Well, apart from the fact that, in my opinion, anybody using the word 'multiverse' in a serious scientific discussion should be lined up against the wall and shot, it's a parsimonious proposal. Given a natural mechanism for the instantiation of a cosmos, and given the requisite topology for the dmensional manifold, it would be a bit silly to rule it out, not least because for this to be the only cosmic inflation would require a barrier to it happening again, which is a failure of parsimony, becaus that barrier constitutes an additional entity, which is a violation of Occam's Razor. Pretty simple when you look at it from the correct perspective.

I note that some think that other cosmic instantiations constitute such a violation. Hopefully I've shown the error of this way of thinking.

If he's right, than anyone looking for a deep reason for three big dimensions is wasting her time. There is no deep reason, it's just contingent.

There's that word again: 'Reason'.

As for contingent, contingent upon what? I think you might mean here that it's just a brute fact, which is not the same. If that's the case, then I agree. Indeed, that's my own view of the universe, namely that it's simply a brute fact. There are very deep reasons for my thinking this, which I have covered ad nauseum, but I'll be happy to go over them again on request.

So how is this particular fine-tuning, that there are three large space dimensions and not more or less, part of a model and not of the universe?

To call it fine-tuning in this context implies that it was tuned. Certainly our existence is contingent upon three extended spatial dimensions, but that's not the same as saying they are fine-tuned.