Quote:
Not all scientific *theories* are testable.


I'd go further than that. It isn't a scientific theory unless it is testable. If it's not testable, it's just hearsay and hypothesis.

This is one of the foundations of the scientific method. A theory must (as I understand it):

- explain current observations
- be verifiable
- make a testable prediction of something that's not been observed yet (otherwise it could have been tailored to fit what we already know).
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-- roger