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Richard Smoley's Blog

Incredible String Theory

The Scientific American article to the left describes some of the controversies of string theory, one of the latest attempts to create a Grand Theory of Everything from a scientific point of view.

I am in no way qualified to make any pronouncements about the validity of string theory, but in its exquisite ingenuity, it’s starting to resemble another piece of theoretical ingenuity: the epicycles of Ptolemy’s geocentric theory.

In short, the idea that the planets revolve around the earth is hard to square with the fact that the planets move retrograde from time to time.

The Ptolemaic theory fixed this problem by positing epicycles—cycles in which the planet revolved around a central point >while revolving around the earth.

The theory of epicycles actually worked pretty well for a while, but as astronomical observation became more precise, more or and more epicycles had to be added to account for the data.

The ultimate solution lay outside the geocentric theory entirely: the Copernican theory that the planets, including the earth, revolve around the sun. Once this theory was modified by Kepler to say that the planets’ revolutions are elliptical rather than circular, it accounted for the evidence much better, and the Ptolemaic theory was discarded.

This need for string theory—which will, it is hoped, bring all other scientific theories together into the same fold seems to be inspired by this hope: if we push our theoretical (and empirical) explorations enough, we will end up with a theory that explains everything through the equations of physics. In the language of Thomas Kuhn’s Structure of Scientific Revolutions, a new paradigm will replace the old.

Only a fool says that something will never happen, but it does not seem to be turning out that way, for the reasons suggested below.

As many people know, Newtonian physics was, in the nineteenth century, considered to be the bedrock of scientific truth. Newtonian physics not only worked in practice, but was believed to describe the world as it actually is.

Only a few small details needed to be ironed out.

These small details turned out to overturn the Newtonian understanding of reality entirely. They gave rise to both Einstein’s theory of relativity and to quantum theory. To a certain degree they replaced Newtonian physics.

These new theories required some adjustments in perspective. Relativity posits that space is curved rather than straight, so it was necessary to turn to non-Euclidean geometry (which previously had been developed almost as a curiosity) to describe certain features of it.

These twentieth-century discoveries made it impossible to claim that the Newtonian view of a universe consisting of lots of little particles knocking one another around like billiard balls was metaphysically true or epistemologically complete.

And yet relativity and quantum theory—validated empirically—pose a problem of their own: the views of the nature of the physical universe that they posit conflict with each other. Moreover, they are exceeding strange in their own right.

I’m reminded of the famous comment by the British geneticist J.B.S. Haldane: “I have no doubt that in reality the future will be vastly more surprising than anything I can imagine. Now my own suspicion is that the Universe is not only queerer than we suppose, but queerer than we can suppose.”

Then, too, the twentieth-century theories did not render Newtonian physics or Euclidean geometry obsolete. The new theorists simply found that it was necessary to make different assumptions to deal with distances and entities that were either surpassingly large (such as galaxies) or surpassingly small (subatomic particles).

And in fact to this day an engineer is likely to use Newtonian physics to calculate the capacity of a bridge to bear weight. And a surveyor will continue to use Euclidean geometry to measure a piece of land.

We are now dealing with scientific paradigms that are starting to look very different from what they were formerly seen to be.

A scientific paradigm is starting to look less like a picture of objective reality (which, as I’ve said in earlier posts, is a problematic thing in its own right) and more like a tool that happens to be useful in dealing with certain practical problems in a specific context.

Meaning that neither Newtonian physics, quantum theory, nor string theory is an objective picture of reality as it is. They are simply conceptual tools that work in a certain set of circumstances.

Thus rather than a scientific equivalent to “one Ring to unite them all,” there will be a number of parallel paradigms, each of them valid within a certain range of practice and useless in others—just as a plumber has a set of wrenches of different sizes, each of which works in cases for which it is suited and not in others.

None of this presents any fundamental difficulties from the scientific point of view—as long as the theories work within the range for which they are intended. It may in fact be necessary to come up with any number of theories and indeed paradigms to account for various aspects of the universe.

To put it another way, the fact that you need a hammer does not mean that sometimes you won’t need a wrench.

This multiplicity of paradigms, should it continue to develop, only presents problems when you are relying on them to tell you how the world really is in some kind of ultimate sense—itself an awkward problem, as I have tried to show in my post “Contradictions in Scientistic Materialism.”

These observations lead me to suppose that in the future, scientific theories and paradigms will be seen less as having a metaphysical value (telling us how the world is) and more as having a pragmatic, utilitarian value (this is what works in X conditions).

And of course you will notice that the validity of scientific models are proclaimed on these very grounds: the fact that they are borne out empirically: that is, they work.

Now that different physical theories seem to work empirically in different contexts, they are starting to look much more than tools than visions of the truth about the universe.

This consideration leads me to another train of thought, but I think it best to save that for another post.
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