“It (the “sudden burst of evolution” hypothesis) was taken quite seriously. The reaction however was to revise the 'gradual change over time' model to allow for sudden bursts followed by stasis (punctuated equilibrium).”
An example, I take it, of what you call a ‘just-so’ story. A narrative, unverifiable and unfalsifiable, but held to be valid, contradicting a theory that likewise continues to be held valid.
“The theories (multiple universe) amount to nothing more than "moving the goalpost" - relegating the issue of the beginning of space and time to some prior universe.”
Another ‘just-so’ story about which, no evidence exists, I presume?
“There does not appear to be a problem proliferating alternative explanations providing those explanations do not entail the possibility of a supernatural cause.”
I take your point. Nevertheless, I foresee a threat posed by any emerging explanation. Accommodations must be proffered. Accommodations threaten upsetting the existing apple cart. The Cambrian Explosion, for instance.
Thank you so much for sharing your insights, dear brother in Christ, and thank you for your encouragements!
All theories are subject to revision as new knowledge is discovered. That is how science advances.
Theory: a coherent group of tested general propositions, commonly regarded as correct, that can be used as principles of explanation and prediction for a class of phenomena: Einstein's theory of relativity. Synonyms: principle, law, doctrine. (from www.dictionary.com)
From the Wiki article, Scientific Theory:
Echoing the scientific philosopher Karl Popper, Stephen Hawking in A Brief History of Time states, "A theory is a good theory if it satisfies two requirements: It must accurately describe a large class of observations on the basis of a model that contains only a few arbitrary elements, and it must make definite predictions about the results of future observations." He goes on to state, "Any physical theory is always provisional, in the sense that it is only a hypothesis; you can never prove it. No matter how many times the results of experiments agree with some theory, you can never be sure that the next time the result will not contradict the theory. On the other hand, you can disprove a theory by finding even a single observation that disagrees with the predictions of the theory." The "unprovable but falsifiable" nature of theories is a necessary consequence of using inductive logic.
The defining characteristic of a scientific theory is that it makes falsifiable or testable predictions. The relevance and specificity of those predictions determine how potentially useful the theory is. A would-be theory that makes no predictions that can be observed is not a useful theory. Predictions not sufficiently specific to be tested are similarly not useful. In both cases, the term "theory" is hardly applicable.
Additionally, a theory is generally only taken seriously if:
It is tentative, correctable, and dynamic in allowing for changes as new facts are discovered, rather than asserting certainty.
By any of these measures, the Theory of Evolution is valid scientific theory. I've used it many times to make testable hypotheses.