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Is That A Fact?

Evolution is Both a Theory and a Fact

Even though I find it almost impossible to believe,

In November 2004, Cobb County, Georgia became the latest government entity to have its school board sued* for attempting to include a sticker in its biology texts like the one in the following box.

This textbook contains material on evolution. Evolution is a theory, not a fact, regarding the origin of living things. This material should be approached with an open mind, studied carefully, and critically considered.

If the above seems reasonable to you, imagine the following sticker in a physics text.

This textbook contains material on gravity. Gravity is a theory, not a fact, regarding a physical phenomenon. This material should be approached with an open mind, studied carefully, and critically considered.

While everything presented in school "should be approached with an open mind, studied carefully, and critically considered", to single out evolution for warning, as the sticker proponents do, implies that it is more suspect than other subjects.

The truth is that the Theory of Evolution, the Theory of Gravity, the Theory of Relativity, Atomic Theory, and all other scientific theories of equal stature are "logical, tested, well-supported explanation[s] for a great variety of facts"

To better grasp what this means, you can think of such theories as analogous to living bodies.  Bodies are built from cells (that organize into tissues that form organs such as hearts, lungs and brains), while scientific theories are built on facts.  Both bodies and scientific theories start small, then develop and mature.  However, whereas bodies age and eventually die, scientific theories continue to develop and grow stronger as the work of science adds new discoveries and insights. 

More than simply a collection of facts, theories built from scientific discoveries and observations possess great explanatory and predictive power.  And, much like living bodies, they are stronger and more powerful than the individual elements from which they are constructed.  (The whole is greater than the sum of its parts.)  So, just as it would make no sense to say that a body is less important or real than the cells from which it is made, it makes no sense to say (or imply) that a scientific theory is less true than its constituent facts.

Because they rest so solidly on fact, scientific theories themselves become fact.  (The Talk.Origins Archive has posted an essay explaining this concept.) 

To confuse such theories with guesses, hunches, speculation or conjecture (as the sticker proponents do with evolution), is to commit a serious fallacy.  At best this makes evolution sticker disclaimers intellectually dishonest, while simultaneously demonstrating their authors' profound misunderstanding of science.  At worst, it perpetrates a fraud.

Words often have multiple meanings.  In this case, according to the Random House Webster's Unabridged Dictionary, the word theory can be used to refer to seven different things.

the·o·ry, n., pl. -ries.
1. a coherent group of general propositions used as principles of explanation for a class of phenomena: Einstein's theory of relativity.
2. a proposed explanation whose status is still conjectural, in contrast to well-established propositions that are regarded as reporting matters of actual fact.
3. Math. a body of principles, theorems, or the like, belonging to one subject: number theory.
4. the branch of a science or art that deals with its principles or methods, as distinguished from its practice: music theory.
5. a particular conception or view of something to be done or of the method of doing it; a system of rules or principles.
6. contemplation or speculation.
7. guess or conjecture.
—Syn. 1. THEORY, HYPOTHESIS are used in non-technical contexts to mean an untested idea or opinion. A THEORY in technical use is a more or less verified or established explanation accounting for known facts or phenomena: the theory of relativity. A HYPOTHESIS is a conjecture put forth as a possible explanation of phenomena or relations, which serves as a basis of argument or experimentation to reach the truth: This idea is only a hypothesis.

Copyright © 1999 Random House, Inc.

The sticker authors use "theory" in a non-technical sense to imply guess, conjecture, contemplation or speculation (definition #6 or #7); however since the context is technical, definition #1 clearly applies.  This play with the word theory makes their sticker argument fallacious.

One could reasonably argue that definition #2 might have applied to Evolutionary Theory when Darwin published The Origin of Species in 1859.  However, the more than 150 years of research and discovery that have developed, expanded and strengthened it since then places it clearly within definition #1 today. 

What does it tell you about the state of scientific literacy in our nation that only one third of us recognize the difference between a guess and a scientific theory?

Additional Resources


(January 13, 2005) U.S. Federal District Judge Clarence Cooper ruled today that the evolution stickers mandated by the Cobb County, GA school board were an unconstitutional violation of the establishment clause of the U.S. Constitution.  He ordered them removed from Cobb County Biology texts.  The Judge's ruling is available for reading online at

(December 20, 2006) The Board of Education of Cobb County, Georgia settled the lawsuit brought against it by parents upset over its requirement to place stickers in Biology texts.

(May 15, 2007) WGBH presents the L.A. Theatre Works play, The Great Tennessee Monkey Trial, based on transcripts from the 1925 Scopes "Monkey Trial".

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original web posting: Saturday, November 20, 2004
last modified: Sunday, August 04, 2013