A troll on my videos dropped a few attempted stump questions in the comments, but this is an opportunity to share a summary explanation of a topic that often confuses the laity.
1. Are scientific theories ever proven?
Not in the mathematics sense that scientists typically use, but they can be in a colloquial sense, if we use the legal definition of “proof” as an overwhelming preponderance of evidence indicating a particular conclusion beyond reasonable doubt. In this sense, we “prove” things by confirming the factual truth of the claim.
2. Has the theory of evolution been proven?
In the sense I just described, yes. Virtually all of the predictions made by evolutionary theory have been confirmed. There are numerous examples of this across multiple fields of study. We could say the same thing about atomic theory, cell theory, and the germ theory of disease, among others. In a colloquial sense, all modern scientific theories are hypotheses that have been effectively proven–by withstanding a substantial battery of tests in critical analysis. So every modern scientific theory is also a fact, but at the same time, a Theory is also a field of study or body of knowledge. So it wouldn’t make sense to prove it. How would you prove music theory, for example?
3. Has Newton’s theory of gravity been proven?
No, because it had a critical failure. It couldn’t account for eccentricities in the orbit of Mercury. But Newtonian gravity was replaced by Einstein’s theory of relativity, and that was proven twice: once by observing stars behind the sun during a solar eclipse in 1919, and again with the discovery of gravity waves just a couple years ago.
I don’t know about Hawking, but Einstein famously said, “No amount of experimentation can ever prove me right; a single experiment can prove me wrong.” Again, Einstein–being a physicist–is talking about mathematic proof.
5. How many successful challenges to evolution theory would be necessary to completely disprove it?
In order to disprove any scientific theory, you need to replace it with another theory that is better supported by, and better accounts for all the evidence. There are so many aspects of evolution now that only some of them even can be disproved anymore. Look at atomic theory for comparison. How could anyone prove at this point that atoms don’t even exist? Considering everything we know to be true of evolution now, to disprove all of it completely would require nothing less than a matrix style illusion or such a flurry of continuous miracles that reality becomes dreamlike. Thus evidence isn’t evident because facts aren’t factual.
I felt compelled to comment on this because this is (for me) the most irritating of all creationist misrepresentations, that evolution is “just a theory”, as if that means that all our best-supported sciences were nothing more than unsupported speculation, like religious beliefs are.