Tuesday, November 29, 2011

"Theories" need a rating system

From my ongoing thought processes resultant from Stephen Hawking's book comes more blogging. But this one wasn't even inspired by my reading, but was a later thought! I have so many more to go!

This blog post is, in part, a result of my ponderings following my "Savannah theory" post of a few months ago.

Is seems to me that even scientists use the term "theory" in a few different ways depending on context but also forum and discipline. And if national economies can be applied with a AAA rating, and much lower, why can't scientific ideas? Surely national economics is at least as divisive and debatable as science.

Anyway, in a Brief History of Time, Hawking says:

"...you have to be clear about what a scientific theory is. I shall take the simple-minded view that a theory is just a model of the universe, or a restricted part of it, and a set of rules that relate quantaties in the model to observations that we make. It exists only in our minds, and does not have any other reality (whatever that might mean). A theory is a good theory if it satisfies two requirements: It must accurately describe a large class of observations on the basis of a model that contains only a few arbitrary elements, and it must make definate predictions about the results of future observations."


"Any physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it. No matter how many times the results of experiements agree with some theory, you can never be sure that the next time the result will not contradict the theory. On the other hand, you can disprove a theory by finding even a single observation that disagrees with the predictions of the theory"


"In practice, what often happens is that a new theory is devised that is really an extension of the previous theory. For example, very accurate observations of the planet Mercury revealed a small difference between its motion and the predictions of Newton's theory of gravity. Einstein's general theory of relativity predicted a slightly different motion from Newton's theory. The fact that Einstein's predictions matched what was seen, while Newton's did not, was one of the crucial confirmations of the new theory."

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