Saturday, 23 June 2012

Thinking of life, the universe and everything

The great hope of physicists such as Stephen Hawking and Lawrence Krauss is that a deep understanding of physical law will ultimately lead to an answer to the ultimate questions. Why are we here? Why does any universe exist at all? Why are the physical laws the way they are? What is the answer to the question of life, the universe and everything?

This question has been bothering me for a long time, ever since I was a small child in fact. When I was taught that we fall because of the force of gravity, I was first confused and then dissatisfied.

I have already discussed why I was confused in an earlier blog post, but essentially it was because it seemed natural to me that anything without support should fall. After all, without support, there's nothing to keep it up! There seemed to be no need to invent some mysterious force called "gravity".

This confusion did not last long. On becoming accustomed to the concept, I could see that it made sense. There is no clear logical reason why something should fall down without support any more than it should fall into the sky if not tied down. Clearly the concept of gravity makes sense.

If only it were not so dissatisfying!

When, as a child, I learned that matter was attracted to other matter, and we are attracted to the earth simply because it's huge, my first instinct was to ask why.

And nobody could answer me. That's just the way it is.

This seemed profoundly weird to me. I anthropomorphised gravity in my mind, imagining it as composed as a host of invisible grasping creatures pulling us down. Even though I knew these creatures were just a visualisation of the impersonal force of gravity, I wondered who had put them there and why it was that they were so interested in bringing matter together. How did this force act over a distance? My intuition suggested that all interaction was local, so then how does the moon feel the gravitational attraction of earth and vice versa? What gives these gravity spirits such a long reach?

That's just the way it is.

I'm older and better informed now and I have long since shed the image of these grasping creatures. I have a rudimentary understanding of general relativity and now I understand that gravity is the result of matter warping space.

But I am no more satisfied. Why is it that matter warps space? As far as I am aware, nobody knows.

We may well find an answer to this question, but this answer will inevitably simply open up a new level of "Why?". It seems clear to me that no physical explanation can ever be immune to "why".

It could be that physical laws are built of infinite layers like some magnificent onion. Boyle's law can be explained in terms of the classical Newtonian dynamics of particles bouncing around. These laws governing the movement of particles can be explained as a consequence of quantum mechanics. Quantum mechanics may yet have some deeper basis which we will discover if we ever manage to unify it with general relativity. These layers may continue ad infinitum, or they we might finally hit bedrock with a perfect understanding of the fundamentals of physics.

And such understanding may yet yield a deeper explanation for why it is that mass and energy warp space.

But no matter what form that understanding finally takes, it seems to me that it remains subject to a child's insistent "why?"

Why should there be only three (perceptible) spatial dimensions? Why is there more matter than anti-matter in at least our portion of the universe? Why was there such low entropy at the big bang? Why did the big bang happen at all?

While none of these questions have definitive answers, I believe most of them will ultimately be answered. Stephen Hawking did a good job of explaining a lot of this stuff in The Grand Design, while Lawrence Krauss recently tackled these types of questions in A Universe From Nothing.

However their explanations are based on deeper mysteries such as string theory, inflationary theory and quantum mechanics. Whatever the ultimate grand unified theory of everything should prove to be, why should the universe be based on this set of equations rather than that set of equations?

It seems to me that these fundamental laws must be arbitrary. At some point we must reach some level of understanding where our understanding of the universe can no longer be explained in terms of deeper principles.

Now, where did these arbitrary laws come from? If they are not derived from more fundamental laws, then we cannot hope to explain them through the usual tools of the scientific method. No experiment can shed any light on them because there is no new relevant evidence to be discovered.

No, the ultimate answer to life, the universe and everything cannot be another set of arbitrary laws, or even the number 42. It must be some mathematical, logical or philosophical principle. Our explanation, if we ever hope to have one, must be grounded not in empirical evidence but in unassailable reason.

If we ever hope to understand the deepest existential questions, then science is not enough to get us there. We need to do some thinking.

And it just so happens that some of us already are.


  1. I don't agree with this line of reasoning. I think, like many scientists have said when refuting the incessant protestations of religion, that such "why?" questions are as nonsensical as pontificating on the colour of jealousy. As Richard Dawkins said in River out of Eden:

    "We humans have purpose on the brain. We find it hard to look at anything without wondering what it is “for”, what the motive for it is, or the purpose behind it. When the obsession with purpose becomes pathological it is called paranoia … But this is just an exaggerated form of a nearly universal delusion."

    The need for a rational, unempirical, philosophical foundation for everything is a yearning to satisfy a fundamentally irrational desire that arises out of our mammalian talent for a certain kind of curiosity that simply does not match well with the universe we live in. This is not to say that such philosophical arguments would necessarily be wrong; only that this is not credible justification for arriving at one.

  2. But that is to misunderstand the kind of why I'm talking about. I'm not talking about purpose, which is what Dawkins was talking about.

    I'm talking about what explanation. Why is it this way and not another way. It's the same curiosity that motivates scientists.

    Neither would I say that we seek an unempirical or philosophical foudnation for everything. We merely seek a foundation, and it seems to me that the ultimate foundation can't be an empirical one.

    This need for a foundation is a good thing. The endless "whys" of a child are a great way for the child to learn about its world (as long as they are not merely attention seeking!)

    I'm not saying we need a foundation so badly that we should invent one out of whole cloth if we don't have one. I'm saying that we should seek the truth because curiosity is a good thing. Unless I'm missing something, that truth can only be approached with philosophy, logic or mathematics.

    1. Yes, you're right that your type of "why" is different to the one I directly critiqued. I'm not certain, however, that your kind of "why" is any more valid. I'd agree that our curiosity should drive us towards these kinds of questions, but I think we have to be wary of asking questions that seem sensical which are in fact nonsensical.

      Now, I know that you have many other lines of argument for your idea of a fundamental universal mathematics, so I don't mean to throw all of those out with this, but I think perhaps that our desire for a final buck, a final why after all the whats, could simply be a question without an answer. I don't think it's safe to simply assume that there is answer; you have to come at it from some other angle with other information that suggests there must be an answer - though I'm sure you'd argue that you do. ;)

    2. The questions I would like answers to are questions like "Why should matter and energy warp space", or "Why are the laws of the universe the way they are?". It seems clear to me that these are rational, reasonable questions.

      It is possible that they have no answers, or at least that those answers are beyond us, but to simply assume that this is the case smacks of the same kind of intellectual laziness that leads incurious theists to answer "because this is how God wanted it".

    3. My response to those questions is not a parallel to the god-of-the-gaps argument. That argument is specifically that there is no *empirical* answer to the questions, thus we must have a metaphysical, theistic answer. My point is *not* that these questions have answers which are simply beyond us, which would indeed be lazy and defeatist, it is that they may be bogus questions whose potential answers are as invalid as the question is, in the same way, as above, that I could ask, "What is the colour of jealousy?" and not deserve an answer.

      It does seem that the questions you pose are rational and reasonable, but as Peter Atkins says, every "why?" question really ought to be deconstructed into a "how?" question if it is to be valid, and I have a feeling that if we did that, and if we found empirical, in-universe answers to those questions, you would push the buck back another stop and find yourself another "why?" question. Eventually, I think such a "why?" question will not deserve an answer.

    4. There may be common ground between our points of view.

      If I am right, and ultimately explanations come from logical argument rather than evidence, then you might ask meaningless questions about logic itself. Why is logic correct? Why can contradictions not be true? Where does logic come from?

      In these cases, I would agree with you. The questions are meaningless. However I'm not sure that questions about the nature or provenance of our universe will ever fall into this category simply by asking why after why.

      I'm curious how Peter Atkins justifies the point of view you quoted. Do you have a link? Are you sure he's not just repeating Dawkins's objection to our tendency to seek purpose rather than explanation?

    5. Unfortunately, I don't have any links to Atkins expounding on that point. He may have done so in one of his books, but I've only heard him say it a few times in passing in talks without further explanation and it seemed like a safe statement to me (still does).

      I would say that "why should matter and energy warp space?", for example, can quite easily and sensibly be, "how does matter and energy warp space?" while "why are the laws of the universe the way they are?" reads to me quite analogously to your example, "where does logic come from?"

    6. It's generally not too hard to play word games and eliminate the whys.

      "Why are the laws of the universe the way they are" can be rephrased a number of ways. "What is the origin of the laws of physics?", "How did the laws of the universe take this form?", "Are the laws of the universe necessary or contingent?", "Could the laws of the universe be otherwise?".

      "How do matter and energy warp space" could be interpreted to ask what is the nature of the warping - how much mass produces how much warping and in what direction. This is already known. To unambigiously ask for an explanation possibly means using the word "why".

      As such, to see this word as a red in itself seems to me a little unfair. If you think that some why questions are meaningless, you need some more reliable criterion than simply the presence of this word.

      It may be that there is no deep explanation of how matter and energy warp space. This may turn out to be a fundamental law. In that case, your two examples turn out to be essentially the same question. Is it really the case that one phrasing is meaningful and the other meaningless? This seems unlikely to me.

    7. You're right that I need more solid criteria, though I can't think of anything rigid off-hand now. Help me out a little: what would you say is the logical criterion which bars "what is the colour of jealousy?" from being a valid question? Unfortunately, my brain being a little tired, all I can think of is, "it's just obvious", but that clearly won't do. :P

    8. I think such questions can be answered, and the answer is an explanation of the incorrectness of the questioner's assumptions.

      The answer to "what is the colour of jealousy" is "no colour, because jealousy is an abstract concept and colour is a property of physical objects only". Similarly, the wind has no colour because it is transparent.

      The answer to my questions might be "there is no explanation, because ..." and here you would have to fill in the gap.

    9. Well, if we go along with the idea of a kind of category error, then I would flip your reasoning on its head in response to your questions and, as an example, take "Are the laws of the universe necessary or contingent?" and say to you that the laws of the universe are invented descriptions which facilitate an understanding of the events we witness around us, and such things cannot appropriately be given such abstract qualities as necessity and contingency. I think here our divergence of opinion would be on the basis of whether or not the laws as we describe them are simply useful tools or whether they are humanity's gradual uncovering of a deeper abstract truth. But that is something I might get to in an email - I really ought to be working!! :P

    10. That doesn't really avoid the issue, though. If these are just tools approximating The Truth, then the question becomes why is The Truth approximately like that modelled by these laws? Is The Truth necessary or contingent?

      Perhaps it is a category error, but if so then the problem of answering the question becomes that of showing that it is a category error. Unlike the colour of jealousy, the question at least appears to be reasonable on the face of it. Showing that the question is a category error may be as difficult a task as answering it more directly.

    11. Some people think, "What is the purpose of the universe?" is a reasonable question on the face of it. That's an intuition we don't share with them. I also don't think your "why?" questions are reasonable on the face of it, but you do. In the same way that the universe could have purpose but I can't prove even beyond reasonable doubt that it's purposeless, I suspect without any great justification that your "why?" questions are tempting but hollow.

    12. Purpose presupposes a designer. It's easy to explain that I don't believe the universe has a purpose because I don't see evidence of a designer. There's no problem answering that question.

      Neither would I call the purpose question meaningless. The meaning is clear, but it reveals an assumption that I disagree with for clear reasons. Even a theist should see why I believe there is no purpose, and should accept that this is perfectly consistent given my world view.

      I see no such grounds for a positive belief that there can be no explanation for why the universe is the way it is.

      "It's just like that" is not an answer. I prefer "I don't know (yet)".

    13. My answer to the question is "I don't know", I merely state that "It's just like that" is an answer that cannot be ruled out simply because of your aesthetic sense which demands some more satisfying answer.

    14. "I don't know" at least tacitly admits that the question is at least sensible, which is all I'm insisting on.

      It may be that there is no answer, or that we can never know it. But I think it is better to try to find an answer rather than give up.

    15. Yes, I wouldn't say that we should give up, I would say, though, that I don't think it will be our place to even attempt an answer until we have a complete description of the universe.

    16. Well, there's no harm in trying!

      The way I see it, it may be possible to explain where the laws of nature come from even without knowing what they are exactly. That seems strange, but if it can be shown that all possible universes with all possible laws of nature must exist, for example, then the particulars of the laws of this universe have no bearing on the issue.