Sunday, January 8, 2012

A question for/about perhaps the smartest septuagenarian on Earth

It's Stephen Hawking's 70th birthday today. A lot of the coverage has been marveling at how he's overcome the odds by living this long with Lou Gehrig's disease. I imagine that when I'm that old or when I'm buffeted with such health challenges that's not what I'd like to be at the center of discussion.

I'm going to take a chance that that's Hawking's view too and instead commemorate his birthday with a question concerning Hawking's work that's been bugging me for a couple month's now (longer even than why we exchange gifts on Christmas and not Epiphany - which, in response to some questions, I really had scratched my head over since before Christmas).

Earlier generations perhaps knew Hawking for his black holes work, but by the time I got familiar with him he was well into obsessing over the grand unified theory issue. Even in Black Holes and Baby Universes and A Brief History of Time, Hawking talked a lot about this - but lately it seems like the only time he isn't talking about a grand unified theory is when he pauses to upset religious people by saying something controversial about God or to generate prime-time news fodder by saying something about aliens.

What's the big deal? Hawking has said that a theory of everything (as I understand it, GUT that incorporates the gravitational force too) would be the "ultimate triumph of science". Why?

I want to be clear about what I am and am not curious about here.

I am not asking why a brand new discovery would be cool. I know that. Obviously finding out something new about the universe is in and of itself important, particularly something this fundamental.

What I am asking is why a single theory for four things would be better than discovering that four things were actually explained by two theories. Or even that in reality we need six theories to best explain these four phenomena.

Is it simply the uniqueness of the number one that makes him so excited about a "theory of everything"? And if that's all it is, is that really a responsible way for a scientist to think about things?

That's really what I'm asking.

I'm also asking, of course, if there's a technical reason for why we should be excited about either a grand unified theory or a theory of everything - because there may be a technical reason I'm not aware of. Is it that we expect that there should be a theory of everything, but we just aren't able to nail it down yet? If that's what it is - if we know it should be there somehow, but haven't figured it out - that would make sense too.

But as it stands I'm not quite clear on why Hawking is so adamant about this. It seems to me we should want to understand the world effectively, regardless of how many distinct relations it takes. Right?


  1. One theory is more likely than two because the probability of A is greater or equal to the probability of A and B. It's more rational to search for a single theory than two, unless you have a compelling reason to do so.

    That, and a single unified theory would be cool as @#$!

  2. Hawking is excited about the prospect of a grand unified theory (btw, a grand unified theory is not a theory of everything. I'm pretty sure Hawking doesn't even think a theory of everything is possible.) not because of some subjective preference for one theory over four, seven or 27 theories, but because it would allow us to understand a great number of things that we don't presently.

    The mistake you make is assuming that a GUT would in effect merely explain things we already know in a different way. That is simply bring a new economy to our understanding rather than a substantive advance of it.

  3. "What's the big deal? Hawking has said that a theory of everything (as I understand it, GUT that incorporates the gravitational force too) would be the "ultimate triumph of science". Why?"

    The grand unified field theory would unify quantum mechanics with Einstein's general relativity.

    It's a bit strange to have the 2 major theories contradicting one another. I expect he's excited to see how they will be reconciled.

    Apart from which, just having such a theory would allow practical applications; you can't move your R&D forward if you don't have the requisite basic theory.

    E.g. (at the risk of sounding like I have been watching too much "Futurama"), what is dark matter? Can you manufacture it on earth? Would it have properties we can exploit in practical technologies (e.g., communications, medical science etc)? and so on.

  4. teqzilla -
    Right - I know TOE and GUT are not the same. I said that in the post, didn't I? And certainly one theory would have to expand our understanding. But then again, so would two theories, right?

    LK -
    This is more along the lines of what I was wondering. Clearly a single theory to incorporate relativity and quantum theory would be important. Is this what a TOE or even just a GUT would do? If that's the case, then the preoccupation seems more justified. Is that essentially what is entailed in a unified theory of the forces?

  5. "Is that essentially what is entailed in a unified theory of the forces? "

    It is my understanding that a unification of quantum mechanics and GR is the major purpose of a unified field theory.


All anonymous comments will be deleted. Consistent pseudonyms are fine.