Facts, Theories and Evolution
In a development that should deeply embarass any Texan, it has been ordered that all Texas biology books will bear a sticker reading "Evolution is a theory, not a fact". I think this would be a good time to clear up a very common misconception about the terms "theory" and "fact".
In everyday usage, a theory is a idea that has not yet been tested in any way that would make a reasonable person assert that it must be true. When proven, it becomes a fact.
In the more precise language of science, this is not what "theory" and "fact" mean.
A fact is an observation. Drop a rock and it falls at a predictable rate downward. Run electricity through a light bulb and you get light. Heat flows from hotter areas of an object towards colder areas. The speed of light in a vacuum is 300,000 kilometers per second. Water freezes at 0 degrees Celsius. These are all facts.
If you have an idea that might explain WHY certain facts are observed you have created a hypothesis. It is the same as what you would call a theory in everyday speech. It is an idea, untested and unproven that might or might not prove to be correct.
Finally, we come to a scientific theory. A scientific theory is a hypothesis that has been repeatedly tested by scientists worldwide. The tests must consistently and repeatedly support a hypothesis before it can be considered worthy of the status "scientific theory". Once a large enough percentage of the scientific community worldwide agree that the tests show that the hypothesis really does match all the known facts and does a better job of explaining the facts than any other available explanation the hypothesis is granted the esteemed title of theory. Scientists NEVER grant any explanation as to why something occurs a title more certain than theory because they are always willing to admit that someday, somewhere, there is a tiny possibility that facts might come to light that disagree with the theory.
Because of this, our most well-accepted explanations of the world are ALL theories. Electricity is a THEORY known as the Electromagnetic THEORY. Rocks fall to the ground in accordance to the THEORY of gravity. Hot things become cold because of the THEORY of thermodynamics.
On equal footing with all the above based on an overwhelming weight of evidence, species slowly change in genetic composition to form new and separate species according to the THEORY of evolution. That's "theory" as a scientific term, not the term "theory" as commonly used in daily speech.
Hey Texans: Don't you think it's time to give your goverment a lesson in vocabulary?