It is well known that the popular usage of “theory” as meaning an unproven idea differs from how scientists use the word. And that allows creationists to wreak all sorts of “only a theory” mischief.
Defenders of science, however, often over-react to this charge by asserting that, in science, “theory” means a well-tested and well-evidenced account. For example the US National Academy of Sciences makes a well-meaning but wrong statement, defining:
Theory: In science, a well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypotheses.
In fact, scientists use the word to mean merely “explanation”, or perhaps “set of explanatory ideas”, and it carries little connotation either way as to whether that explanation is tested or proven. For example “string theory” is highly speculative and unproven. Similarly, we still talk about Newton’s theory of gravity even though we know that it is only approximately correct and that it has been superseded by Einstein’s theories. Continue reading