Green Cheese: A Silly Example of Science

Modified: 2023-08-11 (1:40 PM CDST)

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  The green-cheese hypothesis is a hypothetical example of how science operates.
  • All science starts when someone asks a question.
  • In this case, the question is "What is the Moon made of?"
  • More generally, scientists are people who are always looking for questions to ask.

  • After scientists ask questions, they then answer them, but only tentatively.
  • That tentative or temporary answer is called an hypothesis.
  • Now comes the interesting part.
  • In order to qualify as science, the process must continue, and the hypothesis must be tested.
  • Those three steps, a question, a hypothesis, and the test of the hypothesis, are what constitute the core of science.
    • What are two non-scientific ways of dealing with the green cheese hypothesis?
    • The first might be to vote on it, a popularity-based method.
    • So, I could ask a large number of people whether or not they believed that the Moon was made of green cheese, and if more than 50% agreed, I would accept the hypothesis.
  • Another method might be to go to an authority, someone who knows.
    • We have used this method all of our lives.
    • For example, when we were younger we asked our parents for answers, they were the authorities.
    • So, in this example, we might look for someone who knows cheese.
    • We might ask the Wisconsin Cheese Makers Association; they should know cheese.
  • If they say the Moon is cheese it must be so.
• Of course, we can now see how popularity and authority are not scientific.
  • How would a scientist test the green cheese hypothesis?
    • Obviously, the test would involve some type of visit to the Moon, and the collection of a lunar sample.
    • If the lunar sample is green cheese, then the hypothesis is true.
    • But what if it is not green cheese, is the hypothesis dropped? Not necessarily.
• Confirmation of a hypothesis is powerful, but lack of confirmation is not.
  • Back to the example. Suppose I went to the Moon and did not find green cheese.
  • Someone back on Earth might ask whether I searched the entire Moon, including the side that never faces Earth, or I searched 100 ft. under the surface, and so on.
  • It is possible that the green cheese exists but I just did not find it.
• Disconfirmation usually leads to changes in the hypothesis.
  • For example, the hypothesis might change to: Green cheese is only on the side of the Moon that never faces Earth, or, Green cheese is 100 ft. below the surface of the Moon.
  • Now, these new hypotheses will need to be tested as well.
  • After many modifications of the hypothesis, and after many tests, and after none of those hypotheses and their tests have been confirmed, then that line of investigation may be dropped.
  • (Loss of interest by funding agencies is also a large determinant for the cessation of research. A long history of research without confirming results will likely lead to loss of funds for that project.)
  • That is why some hypotheses may linger on for years after they have been tested and seemingly disconfirmed.

The point is that one confirmation may be sufficient to prove a hypothesis, but no number of failures to confirm can disprove a hypothesis. The situation is profoundly asymmetric.

BTW, the page you are reading was featured by NASA on April 1, 2002. (Under the link "Controversy" on that page.)