Is the Theory of Evolution a fact? Is it silly to even ask such a question when, in most textbooks, we refer to Darwinian Evolution, and other branches of evolution, under the umbrella title of "Theory of Evolution"? Can a theory be a fact?
According to the late Stephen Jay Gould — Harvard professor and leading spokesperson for evolutionary theory right up until the time of his death in 2002 — Evolution, while still a theory, is also a fact. Is it me, or is this approach faintly reminiscent of former President Clinton parsing the meaning of the word "is" in front of a grand jury?
Gould goes on to assert that "'theory' often means 'imperfect fact'--part of a hierarchy of confidence running downhill from fact to theory to hypothesis to guess." Unfortunately, there are no dictionaries in existence today which would describe a theory as "imperfect fact." Rather, dictionaries describe theory as a "proposed explanation," or a "group of general propositions." And, as if the waters were not murky enough with this statement, Gould elaborates, saying that "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."
Gould believed that in the "fact" of evolution, and often asserted that the only unknown about evolution was the exact mechanism. While many have never heard this explanation by Gould, this line of reasoning has been widely quoted and used by proponents of evolution to support what they believe. But this is not a scientific argument, rather, it is a philosophical one. Which is why Gould then tries to offer a relevant example showing how something can be a fact while still having a theoretical component.
What relevant example does Gould offer? Gravity of course. As we well know, an object dropped from a building will drop at a rate, based on it's mass, that can be reproduced over and over, no matter how many times the object is dropped. Based on observation and applied mathematical principles, we know that gravity is predictable, even though we don't know exactly how or why it works the way it works.
As Gould rightly asserts, "Einstein's theory of gravitation replaced Newton's in this century, but apples didn't suspend themselves in midair, pending the outcome." That is a fact, but then Gould tries to borrow on this example to insist that "humans evolved from ape-like ancestors whether they did so by Darwin's proposed mechanism or by some other yet to be discovered." In other words, evolution is like gravity, we know it is real, we just don't know exactly how it works.