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Tuesday, December 02, 2008

The Trouble With Physics

Some time ago, I read Lee Smolin's The Trouble With Physics. (New York: Houghton, 2006)

The trouble, as Smolin sees it, is that physics has become too fixated on string theory. Smolin, a physicist who has contributed to string theory himself, is not sure that string theory is wrong, but he is sure that physics isn't telling us any more about how the universe is made than it did a few decades ago.

The twentieth century was a period when physics produced two important new ways of looking at the universe. These were relativity, which, among other things, led to the use of nuclear energy, and quantum mechanics, which, among other things, led to the development of lasers and semiconductors. Without lasers and semiconductors, computers, as we now use them, would be impossible.

But there have been problems. The main one is that there was no satisfactory way to combine the two theories. String theory is the most common attempt to do so, claiming that "strings" are the fundamental units of matter, and that there are really more than 4 dimensions (3 for space and one for time).

Smolin lists five "Great Problems in Theoretical Physics." (pp. 3-17, chapter 1) They are:
1) combine relativity and gravity into a theory of quantum gravity
2) "resolve the problems in the foundations of quantum mechanics" (p. 8)
3) find out if all the particles and all the forces are the manifestation of a single entity
4) "Explain how the values of the free constants in the standard model of particle physics are chosen in nature." (p. 13)
5) "Explain dark matter and dark energy." (p. 16)

He says that string theory, so far, has not made significant progress in solving these problems. Furthermore, string theory, so far, is not really falsifiable -- it hasn't proposed experiments which could show that it is wrong.

Smolin believes that one of the problems with modern physics is that it is not philosophical enough:

The standard model of particle physics was the triumph of a particular way of doing science that came to dominate physics in the 1940s. This style is pragmatic and hard-nosed and favors virtuosity in calculating over reflection on hard conceptual problems. This is profoundly different from the way that Albert Einstein, Neils Bohr, Werner Heisenberg, Erwin Schrödinger, and the other early-twentieth-century revolutionaries did science. Their work arose from deep thought on the most basic questions surrounding space, time, and matter, and they saw what they did as part of a broader philosophical tradition, in which they were at home. In the approach to particle physics developed and taught by Richard Feynman, Freeman Dyson, and others, reflection on foundational problems had no place in research. Lee Smolin, The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next. New York: Houghton, 2006. pp. xxii-xxiii.

Smolin says that this approach enabled great progress to be made, but goes on to say that:
. . . the problems we're up against today cannot be solved by this pragmatic way of doing science. To continue the progress of science, we have to again confront deep questions about space and time, quantum theory, and cosmology. We again need the kinds of people who can invent new solutions to long-standing fundamental problems. Lee Smolin, The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next. New York: Houghton, 2006. p. xxiii.

Another problem, he says, is that the most important physics departments are biased in hiring. They tend to hire only people who are committed to the approaches they are using already, which cuts out new ideas. He also says that they are biased against women and minorities.

God made us stewards of His creation. Part of our stewardship is learning about it -- doing science. We have, we think, made great progress in going from, say, a belief that there were four kinds of substance to the current belief in many chemical elements. Will we ever really understand how things are put together, at their most basic level? I don't know. I think that some of us are supposed to try. See this post for musings about the topics of this paragraph.

Disclaimer: I am not a professional physicist.

Thanks for reading.

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