Friday, July 24, 2015

Deniers and the Scientific Method

When I made my Global Warming Skeptic Challenge I had the requirement any 'proof' had to be done via the scientific method. I stated the reason for this was to prevent 'Because God said so' arguments (I still received those kinds of arguments but was free to refuse them). Most of the submissions I accepted did not follow the scientific method, but if they were anywhere near the realm of a logical universe I went ahead and accepted them (and some were pushing the limits).

Several people tried to claim global warming isn't real because it violates the scientific method. Their logic was the scientific method requires 100% accuracy. One test failure means the theory is invalid. Therefore, if you can find even one test failure of a global warming theory, the whole thing is invalid. Very bad logic and I showed how the submissions were invalid. Take a look here and here.

Let's refresh our memory of what the scientific method is. There are many ways to say it, but they all state basically the same thing: 1) Observe something; 2) Form a best guess hypothesis to explain the observation; 3) Test the hypothesis; 4) Observe the results; and 5) Repeat as long as necessary until it always passes the test.

It is very simple, but wildly misinterpreted and misused.

A common failure of understanding was stated above, i.e., one test failure completely invalidates the theory. This is not only false, it's total nonsense and even a moments thought will tell you that. If we threw out everything after one failure, nothing would ever be accomplished. A test failure simply means more work needs to be done. It is entirely possible the hypothesis being tested is completely wrong, but it is also entirely possible there is merely one small omission or error that can be easily corrected. Claiming otherwise is a false argument.

Another failure of understanding is the oft-quoted statement 'you cannot prove a negative,' sometimes even quoted as 'you cannot prove or disprove' anything via the scientific method. Both statements are not only false, but very false. The fact is, every experiment proves, or disproves, something. Every valid experiment is designed to do just that. It's called the null hypothesis and is the thing the experiment has to disprove or reject. I usually give the following example: Suppose I tell you the door is locked, but when you try it, you find it is unlocked. You just proved a negative. A little thought will give you any number of similar examples.

Another of my favorites goes to the test. Any scientific test must have what is known as an option to fail. Many people interpret this to mean the theory has an option to fail and this invalidates the scientific validity. No. The option to fail only applies to the test. Suppose I give you a multiple choice question: How much is 2 + 2? You look and see all of the answers are '4'. There is no way you can get it wrong. There is no option to fail. This test says nothing about your understanding of the question. It is the option to fail that makes the test valid. It is never taking that option that makes the theory valid.

And, there is one more failure of understanding that prevents people from accepting science - we may learn new science that invalidates what we think we understand today. This is one of the most common quotes I hear from people who reject the science of manmade global warming. The most common form of this false argument concerns the Newsweek article of the 1970s.

This is one of the worst of the false arguments. Here is an article on this subject that explains it very well. The author, Ethan Siegel, gives a very nice description of science and the process of scientific discovery. Part of this, as he explains, is that we occasionally find something that uproots what we previously thought to be accurate. But, that is only part of the story. We cannot simply throw away everything we previously understood. As Siegel explains, there are three requirements for a revolutionary scientific advancement:

1.) It has to reproduce all the successes of the previously existing theory.
2.) It has to explain the new results that contradicted the old theory.
3.) It needs to make new, testable predictions that have not been tested before, and that can either be confirmed and validated or refuted.
That first part is really important to our discussion here. Is it possible we will learn something new about climate change that we don't know about today? Absolutely. But, and this is the important part, any new understanding has to be able to explain everything we understand today. In other words, all of the science we know today will have to become part of the new understanding. When Einstein developed his theory of relativity, Newtonian mechanics were not discarded. It is part of relativity and, if you do relativity correctly, you get Newtonian mechanics at low velocities (less than about 90% the speed of light), which is why our world is dominated by Newtonian mechanics.

As a result, any advances in science will increase our understanding of climate change, but never invalidate it. This is true because any advancement must be able to explain all we observe today as part of the advancement. It is building process, not a tearing-down one.


  1. There is another option - the test used to falsify a hypothesis may be wrong. So if a hypothesis or theory has a lot of explanation value, it may still be retained even though it fails some of the tests.

    An example I can think of is Copernicus' theory of heliocentrism. The theory predicted impossibly large background stars. It later turned out the prediction of impossibly large background stars was incorrect as the apparent size of the stars as seen from earth turned out to be an optical illusion.

  2. That is why we have peer review and repeatability.

  3. "A suspence[sic] novel by Christopher Keating"

  4. Thanks. Like they say, never be your own copy eiditor. ;)