Why Evolution is a fact, but how it works is a theory.

skulls.gif&usg=AFQjCNG9ivk0CfyPHiyh2c6RgiMW9EOTvAEvolution is a fact. How evolution works is a theory.

“In the American vernacular, ‘theory’ often means ‘imperfect fact’—part of a hierarchy of confidence running downhill from fact to theory to hypothesis to guess. Thus the power of the argument: evolution is ‘only’ a theory and intense debate now rages about many aspects of the theory.

If evolution is less than fact and scientists can’t even make up their minds about the theory, then what confidence can we have in it?

Well evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world’s data. Theories are structures of ideas that explain and interpret facts. Facts don’t go away when scientists debate rival theories to explain them. Einstein’s theory of gravitation replaced Newton’s in this century, but apples didn’t suspend themselves in midair, pending the outcome.”

- Stephen J. Gould, ” Evolution as Fact and Theory”; Discover, May 1981

Let’s consider evolution in light of another scientific fact - gravity. Gravity is also fact. How gravity works is a theory. Current theories about gravity might be disproved, but gravity itself remains a fact. 

A number of terms have been attached to Darwin’s theory although they are commonly misunderstood.

Survival of the fittest does not mean survival of the strongest, smartest, fastest or best camouflaged. Survival of the fittest means that an organism that is best adapted to its ecological niche is more likely to create more offspring than less fit individuals. Consider the garden slug as an great example of fitness for survival.

Natural selection is Darwin’s theory of how the environment works on species. Individuals that are most successfully reproducing viable offspring form the core gene pool of a species. Environmental forces determine which individuals survive.

The evidence for Darwin’s theory of evolution grows more unimpeachable as science discovers more about chemistry, geology, and biology.

Take a look at your dog. He’s a perfect display of the mechanisms of evolution. If he’s anything other than a 30 pound dingo looking mutt, the gene’s he displays that make him a cock-a-poo, German Shepard, or Bouvier (my favorite) were selected from an existing gene pool by humans to make him what he is. While all dogs are the same species and a great dane can breed (theoretically) with a chiwawah, you get the idea. His genes have been modified over time to make him different than he was.

So, The Theory of Evolution does not describe evolution as a supposition. It is the the current thinking about how the fact of evolution manifests itself.