What about astronomy, cosmology, archeology, paleontology, volcanology, evolutionary biology, cladistics, macroeconomics, etc., which do not allow us to "repeat and predict," as you say?
Some of these cases can be rescued by considering "retrodiction"[1][2] as valid substitute for prediction in the right circumstances, but not all.
I personally think the analysis of the Mott problem[3] points the way to the solution to some of these kinds of issues. That is, a prediction can take the form of a likelihood function which assigns high probabilities to certain combinations of events and low probabilities to others. Theories with low perplexity[4] can be considered correct even if they can't make predictions, and the study of such theories can be scientific. But as far as I know I am the only one who thinks so.
Some of these cases can be rescued by considering "retrodiction"[1][2] as valid substitute for prediction in the right circumstances, but not all.
I personally think the analysis of the Mott problem[3] points the way to the solution to some of these kinds of issues. That is, a prediction can take the form of a likelihood function which assigns high probabilities to certain combinations of events and low probabilities to others. Theories with low perplexity[4] can be considered correct even if they can't make predictions, and the study of such theories can be scientific. But as far as I know I am the only one who thinks so.
[1]: https://en.wikipedia.org/wiki/Retrodiction
[2]: https://afdave.wordpress.com/2007/09/04/sir-karl-popper-and-...
[3]: https://en.wikipedia.org/wiki/Mott_problem
[4]: https://en.wikipedia.org/wiki/Perplexity