"Any scientific theory must be based on a careful and rational examination of the facts. In the scientific method, there is a clear distinction between facts, which can be observed and/or measured, and theories, which are scientists’ explanations and interpretations of the facts. Scientists can have various interpretations of the outcomes of experiments and observations, but the facts, which are the cornerstone of the scientific method, do not change."
"A theory must include statements that have observational consequences. A good theory, like Newton’s theory of gravity, has unity, which means it consists of a limited number of problem-solving strategies that can be applied to a wide range of scientific circumstances. Another feature of a good theory is that it formed from a number of hypotheses that can be tested independently."
"A scientific theory is not the end result of the scientific method;
theories can be proven or
rejected, just like
hypotheses. Theories can be improved or
modified as more information is gathered so that the accuracy of the prediction becomes greater over time."
What is a Scientific Theory? | Definition of Theory
Is the Big Crunch a cosmological theory?
Is the Big Freeze a cosmological theory?
What about the Big Rip? Is that a theory?
Which of these are scientific theories, and which are not?