On Wikipedia.com, under David Attenborough’s page, David Attenborough is quoted to have said that evolution is a fact but natural selection is a theory:
“People write to me that evolution is only a theory. Well, it is not a theory. Evolution is as solid a historical fact as you could conceive. Evidence from every quarter. What is a theory is whether natural selection is the mechanism and the only mechanism. That is a theory. But the historical reality that dinosaurs led to birds and mammals produced whales, that’s not theory.”
Is Attenborough accurate? Is natural selection still just a theory? If natural selection is not the mechanism behind the process of evolution, then what is? What could be? What are the alternatives? And how is it even possible to know that evolution is a fact if we don’t even know the mechanism behind its process?
Posted: December 31st 2010
Reed Braden www
A theory, in the scientific sense, is an informed, tested explanation of the observed facts. So, yes, it is a fact that evolution has occurred, and it is a fact that evolution often occurs through natural selection (other times, through sexual selection, artificial selection, geographical isolation, etc.), but natural selection and the broader theory of evolution are both considered theories in the scientific sense.
Colloquially, the word theory means a wild guess or an untested hypothesis, so I avoid using the word theory among non-scientists. Inasmuch as gravitational theory, atomic theory, the germ theory of disease, and evolutionary theory are all proved beyond reasonable doubt to be correct, I find it best to refer to them as laws and facts among the general public, since they might as well be called facts. As an added bonus, this really pisses off mathematicians.
Posted: January 5th 2011
bitbutter www
I don’t think Attenborough is correct, or at least he’s glossing over disagreement about the meaning of 'theory’ and 'fact’ in scientific circles.
My understanding has been that common descent (including 'dinosaurs led to birds and mammals produced whales’) is a theory. But like the theory of gravity, it’s one with a very strong body of evidence, that has yet to be overturned.
Wikipedia has an illuminating page on the use of 'fact’ and 'theory’ in this context.
Posted: January 5th 2011
Mike the Infidel www
Yes. Evolution is an observed fact. Natural selection is a theory which proposes an explanation of that observed fact. And calling it “just“ a theory is doing it a disservice. In science, a theory is the single most tested and verified model we can achieve. Ideas do not reach the status of “theory” unless they pass rigorous testing and scrutiny.
Posted: January 2nd 2011
George Locke
It’s a fact that objects fall to the Earth, and that planets orbit the sun. It’s a theory that the force of gravity between two objects is proportional to the product of their masses divided by the square of the distance between the objects. So, gravity is a fact and a theory. I should point out that the mechanism of gravity is hard to figure out. Loosely speaking, there is no quantum theory of gravity, so there are important, unanswered questions about gravity. Nevertheless, gravity is a fact.
It’s a fact that DNA evidence and the fossil record show a historical chain of gradual change built up over time, with speciation and so forth. This is the 'fact of evolution’. The theory of evolution by natural selection is that the gradual changes we see in nature are caused by natural selection (plus undirected mutation).
Posted: January 2nd 2011