It was only when Einstein's theory of relativity was published in 1915 that physicists could show that Mercury's "anomaly" was actually because Newton's gravitational theory was incomplete.
2003, Bill Bryson, A Short History of Nearly Everything, BCA, p. 118:
The world would need additional decades [...] before the Big Bang would begin to move from interesting idea to established theory.
2009, Richard Dawkins, The Greatest Show On Earth: The Evidence for Evolution, Bantam, p. 10:
Scientists and creationists are understanding the word "theory" in two very different senses. Evolution is a theory in the same sense as the heliocentric theory. In neither case should the word "only" be used, as in "only a theory".
Some of the most beautiful and thus appealing physical theories, including quantum electrodynamics and quantum gravity, have been dogged for decades by infinities that erupt when theorists try to prod their calculations into new domains. Getting rid of these nagging infinities has probably occupied far more effort than was spent in originating the theories.
In scientific discourse, the sense “unproven conjecture” is discouraged (with hypothesis or conjecture preferred), due to unintentional ambiguity and intentional equivocation with the sense “well-developed statement or structure”.
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