1.3. Scientific Theory http://www.ck12.org
Keep It Simple
The formation of scientific theories is generally guided by the law of parsimony. The wordparsimonymeans
“thriftiness.” The law of parsimony states that, when choosing between competing theories, you should select the
theory that makes the fewest assumptions. In other words, the simpler theory is more likely to be correct. For
example, you probably know that Earth and the other planets of our solar system orbit around the sun. But several
centuries ago, it was believed that Earth is at the center of the solar system and the other planets orbit around Earth.
While it is possible to explain the movement of planets according to this theory, the explanation is unnecessarily
complex.
Q:Why do you think parsimony is an important characteristic of scientific theories?
A:The more assumptions that must be made to form a scientific theory, the more chances there are for the theory to
be incorrect. If one assumption is wrong, so is the theory. Conversely, the theory that makes the fewest assumptions,
assuming it is well supported by evidence, is most likely to be correct.
Summary
- A scientific theory is a broad explanation that is widely accepted because it is supported by a great deal of
evidence. - Examples of theories in physical science include Dalton’s atomic theory, Einstein’s theory of gravity, and the
kinetic theory of matter. - The formation of scientific theories is generally guided by the law of parsimony. According to this law, the
simplest of competing theories is most likely to be correct.
Vocabulary
- scientific theory: Broad explanation that is widely accepted because it is supported by a great deal of evidence.
Explore More
Watch the first presentation by Dr. Eugenie Scott at this URL and then answer the questions below.
http://www.youtube.com/watch?v=ItxVLu8J_d0 (9:50)
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/54916- How does Dr. Scott define scientific theory?
- From most to least important in science, how would Dr. Scott rank the following concepts? theory, fact, law,
hypothesis - Based on the presentation, explain the importance of theories in science.
Review
- What is a scientific theory?