Claims I wish I understood better

by on June 6, 2009 at 7:27 am in Philosophy, Religion, Science | Permalink

This is from the July/August issue of Discover magazine:

Hawking is now pushing a different strategy, which he calls top-down cosmology.  It is not the case, he says, that the past uniquely determines the present.  Because the universe has many possible histories and just as many possible beginnings, the present state of the universe selects the past.  "This means that the histories of the Universe depend on what is being measured," Hawking wrote in a recent paper, "contrary to the usual idea that the Universe has an objective, observer-independent history."…Hawking's idea provides a natural context for string theory.  All those universes might simply represent different possible histories of our universe.

1 dearieme June 6, 2009 at 7:33 am

“Because the universe has many possible histories and just as many possible beginnings”: what can “possible” possibly mean here?

2 Billy June 6, 2009 at 8:12 am

It sounds like he’s speaking of waveform collapse, or a form of it. Or rather, the way you “measure” something “collapses” its possibilities into an “observer-dependent” reality. For example, if you want to measure an electron as a wave, the electron’s possibilities will collapse and it will “become” a wave. Or, if you want to measure an electron as a particle, the electron’s possibilities will collapse and it will “become” a particle. Thus were someone so measure the beginning of the universe in different ways, its state may collapse for the observer into a new beginning. It also seems to be implying that string theory has its own form of collapse.


3 indiana jim June 6, 2009 at 8:46 am

Russ R. wrote: ” [he] is now coming up with increasingly contrived and elaborate storylines in a failing attempt to maintain audience interest (and research grant funding).”

This sound a lot like what happened in the area of mathematical economics over the past, oh, 30 or 40 years where increasing usage of stylized facts to motivate ever more complex models with ever greater number of multiple equlibria have led to: fewer operatoinal propositions and naturally less debate about operational issues.

As Billy (above) put it: Oy!

4 dis June 6, 2009 at 9:11 am

i’m a physicist and not all advanced physics has jumped the shark. but string theory definitely has. they substitute ancy math for understanding and fall down into gibberish. they also have no connection with experiment nor they want to, nor they can

when a field is disconnected from experimental reality, it’s not science anymore. string theory is neither descriptive nor predictive of any past or future experiments

5 Edward Burke June 6, 2009 at 9:42 am

If the answers don’t lie in the alchemical notebooks of Isaac Newton, then I propose the following: no cosmological or astrophysical theory proposed by any spectator native to this planet will divert the Virgo Supercluster from hurtling towards the Great Attractor at any velocity less than 600 km/s. (I am not counting on receipt of any observational contributions from a spectator in the Norma Cluster, obviously.)

6 Michael F. Martin June 6, 2009 at 12:32 pm

See the Free Will Theorem by Conway and Kochen

7 improbable June 6, 2009 at 1:59 pm

Before anyone rushes to bash science / physics / cosmology / string theory, do keep in mind that this might just be Hawking and he might not make sense to anyone. Already-famous scientists can and do publish some pretty crazy speculations, and are tolerated by the field but don’t become mainstream unless they lead to serious results. (For instance, read almost anything by ‘t Hooft in the last 10 years.)

As a string theorist and one who’s worked on the basics of quantum theory, the quoted paragraph doesn’t make any sense to me at all. But it’s a long long way from having anything to do with what I or any of my colleagues work on day to day, and make progress in understanding.

8 Walt French June 6, 2009 at 3:07 pm

As an investment type, I draw the analogy to the problem of hiring investment managers who have abiding, or structural skill. A key difficulty is retrospect bias: only those whose results are strong enough to be touted are considered, further exacerbating the challenge of distinguishing Shakespeare from one of the many millions of prolific monkeys.

Likewise, if we don’t have a Bayesian prior about the history of the Universe (how could we?), how can we assess the path from the big bang to the present, when many explanations contend? Without a meta-theory, there’s no way to to the simple T-test between contending distributions. We are pushing into many questions that go beyond our hard, seven nines observations, and don’t know whether constants really are constant, what has caused the empirical regularities that we see, etc. What do we fix and what do we test?

Kuhn’s wonderful history, “The Structure of Scientific Revolution,” lays out case studies where not the envelope, but the Academy pushed back. Most new paradigms, even if subsequently supported by observations, are ridiculed as incongruent with the status quo. (Examples: the Copernican Revolution, Newton’s pure-math explanation of gravity, even key parts of Einstein’s revolution were dismissed as abhorrent, unbelievable or even inconsistent in their initial forms with observation. Famously, even Einstein rejected quantum physics.) Further, many such efforts are doomed to collapse in inconsistency.

The challenge for any knowledge worker is how much of an open mind to keep, and how to balance long shots, evolving approaches and ossified theory for our individual purposes. Hawking’s job in this world seems to be to help provide a mental framework for just that consideration of the nearly impossible. Few readers of this forum will NEED to make sense of the view, but perhaps it will inform us when we contend with problems where our existing framework doesn’t provide enough support.

9 ZBicyclist June 6, 2009 at 10:38 pm

I’d be happier if history becomes more like one of the Sciences than if physics becomes more like one of the Humanities.

10 Michael F. Martin June 6, 2009 at 11:59 pm

Roger Penrose has conjectured that nature, perception, and models of nature form a feedback loop. If both Hawking’s and Penrose’s conjectures are correct, then there is only one history and future at each moment, but that history and future changes from moment to moment.

11 dj superflat June 7, 2009 at 1:17 pm

i still don’t get how observation/measurement by sentient beings is prioritized, when, of course, we interact with the universe (take measurements) by physical interaction of the same type particles/atoms/whatever they ultimately are have all the time. so our interaction with the universe is nothing special, just all those particles bouncing into each other should have the same effect. so you don’t have a universe waiting for a sentient observer to fix its character/history/whatever, you have a universe that has always had the interactions necessary to fix it. (this is the same reason the schrodinger’s cat thought experiment is silly (the cat’s various particles interacting with each other means there’s no indeterminate state).)

12 improbable June 7, 2009 at 1:30 pm

“i still don’t get how observation/measurement by sentient beings is prioritized”

It isn’t. This insidious idea refuses to die. We do now understand how to recover the appearance of measurement selecting the state, and (as you say) it’s all about measuring equipment being big & poorly isolated from the universe, not about it being sentient. This all goes by the name of decoherence, and was worked out in the 80s by Zurek & co.

Whether Hawking wishes to revive a special role for humans, or thinks we are forced to, I don’t know. But I wouldn’t jump to conclusions from this paragraph.

13 BC June 7, 2009 at 4:05 pm

Like Obi Wan Kenobi, Richard Rorty has become more powerful in death . . . .

14 Rama June 8, 2009 at 7:26 am

Wonder whether this is similar in some ways to Heisenberg’s observer ( “uncertainity principle”) , where the observer impacts the observation by the very fact of making the obsrvation.
An earlier comment by Walt French referenced Kuhn’s ” Structure of Scientific Revolutions” . This is easily the best (and very readable) book to understand how Scientific paradigms come about and surprise , they don’t come about the way most scientists tell the story.
Science , to most laymen and many scientists is seen as an activity that leads to discovering “the truth.” But the tools used may restrict or determine what truth is being discovered .
There is probably some linkage to Kurt Godel’s theorem as well: “there would always be some propositions that couldn’t be proven either true or false using the rules and axioms … of that mathematical branch itself ” and perhaps in a sense this applies to Physics and astrophysics as well .
Having dabbled in Physics and History of Science in previous lives , I am not as discomforted by Hawking’s observation as many of the commenters are .
Science is often a teleological activity
Teleological :”Belief in or the perception of purposeful development toward an end, as in nature …”
As far as the astrophysicists are concerned all they need to wonder is whether ( as a paper dealing with History of Science put it) the field’s present past has a future .

15 anon June 9, 2009 at 10:34 am

I’d be happier if history becomes more like one of the Sciences than if physics becomes more like one of the Humanities.

I’d be happier if the sciences became a bit more scientific and stopped trying to be like the cool kids in english lit or performance art….

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