10-16-2003, 08:51 AM
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#43 (permalink)
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Banned
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http://home.xnet.com/~blatura/skep_1.html
Quote:
1.2: What is the difference between a fact, a theory and a hypothesis?
In popular usage, a theory is just a vague and fuzzy sort of fact. But to a scientist a theory is a conceptual framework that explains existing facts and predicts new ones. For instance, today I saw the Sun rise. This is a fact. This fact is explained by the theory that the Earth is round and spins on its axis while orbiting the sun. This theory also explains other facts, such as the seasons and the phases of the moon, and allows me to make predictions about what will happen tomorrow.
This means that in some ways the words fact and theory are interchangeable. The organisation of the solar system, which I used as a simple example of a theory, is normally considered to be a fact that is explained by Newton's theory of gravity. And so on.
A hypothesis is a tentative theory that has not yet been tested. Typically, a scientist devises a hypothesis and then sees if it "holds water" by testing it against available data. If the hypothesis does hold water, the scientist declares it to be a theory.
An important characteristic of a scientific theory or hypotheis is that it be "falsifiable". This means that there must be some experiment or possible discovery that could prove the theory untrue. For example, Einstein's theory of Relativity made predictions about the results of experiments. These experiments could have produced results that contradicted Einstein, so the theory was (and still is) falsifiable.
On the other hand the theory that "there is an invisible snorg reading this over your shoulder" is not falsifiable. There is no experiment or possible evidence that could prove that invisible snorgs do not exist. So the Snorg Hypothesis is not scientific. On the other hand, the "Negative Snorg Hypothesis" (that they do not exist) is scientific. You can disprove it by catching one. Similar arguments apply to yetis, UFOs and the Loch Ness Monster. See also question 5.2 on the age of the Universe.
1.3: Can science ever really prove anything?
Yes and no. It depends on what you mean by "prove".
For instance, there is little doubt that an object thrown into the air will come back down (ignoring spacecraft for the moment). One could make a scientific observation that "Things fall down". I am about to throw a stone into the air. I use my observation of past events to predict that the stone will come back down. Wow - it did!
But next time I throw a stone, it might not come down. It might hover, or go shooting off upwards. So not even this simple fact has been really proved. But you would have to be very perverse to claim that the next thrown stone will not come back down. So for ordinary everyday use, we can say that the theory is true.
You can think of facts and theories (not just scientific ones, but ordinary everyday ones) as being on a scale of certainty. Up at the top end we have facts like "things fall down". Down at the bottom we have "the Earth is flat". In the middle we have "I will die of heart disease". Some scientific theories are nearer the top than others, but none of them ever actually reach it. Skepticism is usually directed at claims that contradict facts and theories that are very near the top of the scale. If you want to discuss ideas nearer the middle of the scale (that is, things about which there is real debate in the scientific community) then you would be better off asking on the appropriate specialist group.
1.4: If scientific theories keep changing, where is the Truth?
In 1666 Isaac Newton proposed his theory of gravitation. This was one of the greatest intellectual feats of all time. The theory explained all the observed facts, and made predictions that were later tested and found to be correct within the accuracy of the instruments being used. As far as anyone could see, Newton's theory was the Truth.
During the nineteenth century, more accurate instruments were used to test Newton's theory, and found some slight discrepancies (for instance, the orbit of Mercury wasn't quite right). Albert Einstein proposed his theories of Relativity, which explained the newly observed facts and made more predictions. Those predictions have now been tested and found to be correct within the accuracy of the instruments being used. As far as anyone can see, Einstein's theory is the Truth.
So how can the Truth change? Well the answer is that it hasn't. The Universe is still the same as it ever was, and Newton's theory is as true as it ever was. If you take a course in physics today, you will be taught Newton's Laws. They can be used to make predictions, and those predictions are still correct. Only if you are dealing with things that move close to the speed of light do you need to use Einstein's theories. If you are working at ordinary speeds outside of very strong gravitational fields and use Einstein, you will get (almost) exactly the same answer as you would with Newton. It just takes longer because using Einstein involves rather more maths.
One other note about truth: science does not make moral judgements. Anyone who tries to draw moral lessons from the laws of nature is on very dangerous ground. Evolution in particular seems to suffer from this. At one time or another it seems to have been used to justify Nazism, Communism, and every other -ism in between. These justifications are all completely bogus. Similarly, anyone who says "evolution theory is evil because it is used to support Communism" (or any other -ism) has also strayed from the path of Logic.
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Just thought some people might need to read this. There is a difference between scientific theory, ie, evolution and theory, ie, God or the invisible snorg.
thanks for reading.
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