August 17, 2005


Einstein's Legacy -- Where are the "Einsteinians?" (Lee Smolin, Logos)

Einstein’s single goal in science was to discover what he called theories of principle. These are theories that postulate general rules that all phenomena must satisfy. If such a theory is true, it must apply universally. In his study of physics he identified two existing theories of principle: the laws of motion set out by Galileo and Newton, and thermodynamics. [...]

So what is Einstein’s real legacy? Are any of us his followers? In this centennial year, there will be many who claim the mantle. That includes the community of relativists, but many of them rarely look beyond the theory. Instead they study it by finding solutions on computers or by looking for gravity waves. There are also a few physicists who follow Einstein in rejecting quantum theory and in searching for an alternative. Einstein would have been happy that some scientists agree with him, but he likely would have been critical that most work in that area ignores the problem of unification.

Some string theorists will claim to be Einsteinians, and certainly Einstein would have approved of their search for a unification of physics. But here is how Brian Greene, in his last book, describes the state of the field: “Even today, more than three decades after its initial articulation, most string practitioners believe we still don’t have a comprehensive answer to the rudimentary question, What is string theory? . . . Most researchers feel that our current formulation of string theory still lacks the kind of core principle we find at the heart of other major advances.”

Einstein’s whole life was a search for a theory of principles. It is hard to imagine he would have sustained interest in a theory for which, after more than 30 years of intensive investigation, no one is able to put forward any core principles.

He may in this regard have been happier with approaches to quantum gravity that stay closer to the core principles of relativity. For example, loop quantum gravity preserves his discovery that space and time have no fixed background, and it also provides an answer to Einstein’s questions of how to go beyond the continuum. But Einstein would have found unacceptable all approaches to quantum gravity that take quantum mechanics as fundamental, including string theory and loop quantum gravity. Einstein never wavered from his rejection of quantum mechanics. His motive for making a unified field theory was not to extend the domain of quantum mechanics; it was rather to find an alternative to quantum mechanics. No research program that accepts quantum mechanics as a given can count itself to be within Einstein’s legacy.

I think a sober assessment is that up until now, almost all of us who work in theoretical physics have failed to live up to Einstein’s legacy. His demand for a coherent theory of principle was uncompromising. It has not been reached—not by quantum theory, not by special or general relativity, not by anything invented since. Einstein’s moral clarity, his insistence that we should accept nothing less than a theory that gives a completely coherent account of individual phenomena, cannot be followed unless we reject almost all contemporary theoretical physics as insufficient.

May as well, no one buys it anyway.

Posted by Orrin Judd at August 17, 2005 4:50 PM

Open up your copy of Johnson's "Modern Times", read chapter one "A Relativistic World" and all will be even clearer.

Posted by: Mike Daley at August 17, 2005 11:55 PM

Despite all the claims of the string theorists, gravity can not be quantized if black holes actually exist. Quantum theory accounts for the fundamental forces via the exchange of particles: gluons for the strong force, mesons for the weak force, photons for the electromagnetic force, and gravitons for gravity. By definition no particle can escape from a black hole, therefore under quantum mechanics a black hole would have no gravitational influence, contradicting general relativity.

Posted by: jd watson at August 18, 2005 3:01 PM

Except for the Hawking radiation, so I don't think that works the way you think it does.

Posted by: Harry Eagar at August 18, 2005 5:20 PM

Harry: You are ignorant of physics. The Hawking radiation "supposedly" arises outside the event horizon, so your criticism is totally misinformed.

However, I even have the audacity to question Hawking. Hawking radiation "supposedly" occurs by the capture of one virtual particle of a virtual pair creation, resulting in the emission of the other particle. Hawking therefore claims that a black hole is emitting radiation and hence "evaporating". First, this absorption of a virtual particle and the emission of the other violates the Heisenberg Uncertainty Principle, but more importantly, it results in an increase of the mass/energy content of the black hole. Therefore, the balck hole is not evaporating at all, but increasing in mass/energy. Where does this energy come from? Hawking is silent on this issue.

If you believe in quantum mechanics, you must conclude that if black holes exist, they have no gravitational field, violating mass/energy conservation, and that they have no electrical charge, violating conservation of charge.

I, myself, am a Einsteinian, and therefore think that quantum mechanics is a statistical ensemble theory which does not account for the actual individual phenomena.

Posted by: jd watson at August 19, 2005 5:45 AM

Harry: You really ought to read the sources you link to:
"The prediction that black holes radiate due to quantum effects is often considered one of the most secure in quantum field theory in curved space-time. Yet this prediction rests on two dubious assumptions ..."
A quote directly from the first sentences of the abstract you cited.

Posted by: jd watson at August 19, 2005 5:52 AM

Orrin's link, not mine, jd.

My physics adviser and I have discussed this at length. I am no physicist though I think I have some slight concept with the underlying question, thanks to his guidance.

I do not 'believe' in either QM or relativity as a nearly complete theory. Nor does my adviser.

His view is that eventually somebody is going to come up with a theory that reconciles the contradictions between QM and relativity "and when it happens, it's going to turn out to be really simple."

Sounds right to me.

Posted by: Harry Eagar at August 19, 2005 5:08 PM

Of course, one of the ways you know the theories have gone off track is their inelegance. That's the core assumption of Einstein and Western Physics and proceeds from our monotheism: Creation isn't going to be messy.

Posted by: oj at August 19, 2005 5:57 PM
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