I currently hold that Noah's Flood was a localized event. (I'm not going to go into a huge defense of this position here because the purpose of this post is just to make a quick point, which Noah's flood being local is not it.) A friend of mine gave me two pieces of evidence that he states can only be explained by a geographically world-wide flood. These two being the large amounts of sediment all over the land and aquatic fossils being found on top of many mountains. He told me that this was evidence that the whole world was covered by water, and further concluded that could only have been Noah's flood (worldwide).
I have to agree that a worldwide flood could explain that evidence, and a local flood can not. However, that does not mean that the local-flood hypothesis has been overturned. How? All I have to do is provide an alternative explanation for the presented evidence that is consistent with my worldview. I happen to believe that the universe and earth are billions of years old. I also subscribe to the planetary formation theory that states that all planets begin with a rocky core, and some of those rocky cores are entirely covered by water for great expanses of time.
We both agree that evidence shows that the earth was covered by water at some point in time. One side says that it was at the time of Noah's flood, the other side says that it was much earlier. Both sides have provided an explanation of the evidence. So, that evidence may not be considered to exclusively support one view, while falsifying the other.
Please notice three things here:
1. We need to always be looking for alternative explanations of evidence that we are tempted to say supports our worldview exclusively.
People tend to be able to accept this (although there are many hold-outs). This is part of being responsible in what we claim about our evidence for our worldview. We need to not only look for alternative explanations for evidence in other worldviews, but we need to be able to accept when a supporter of another worldview provides an explanation of the evidence.
2. We need to be aware that the alternative explanation in the other worldview may not be within the specific belief of the worldview that we are attacking.
As with my example above, the evidence cannot be explained by the local flood hypothesis; however, it can be explained by another part of the my worldview- planetary formation. This is probably the most difficult to individuals outside a worldview to do. Typically, our attention is on the view we are disputing- if we can't find an alternative explanation for the evidence (ala #1), we consider the belief falsified. This is where our academic responsibility is taken to the next level: we need to look at other beliefs within the overall worldview to find an alternative explanation. We also need to allow the adherents of other worldviews to show how another belief in that worldview can explain the evidence.
3. For worldviews that have much overlap, recognize the overlap.
A. I add this third point specifically because there are many competing beliefs that are in competition within a broader worldview (such as the age of the universe/earth and Noah's flood within Christianity). Many internal debates tend to cause much division among the adherents to a worldview (this is not just limited to Christianity either).
B. However, on the bright side, this can also come in handy if we recognize overlap among worldviews we are arguing against- if they overlap with a belief that cannot explain a certain piece of evidence, then we have delivered a blow to both worldviews...at least until we have verified that each worldview does not have an alternative explanation elsewhere in the worldview or a competing belief (ala 3A) that can explain it.
C. 3A must be remembered by the adherents of a worldview when 3B is used against them. If a particular belief in a worldview has been shown to be falsified (and alternative explanations have been defeated), the victims of 3B can't be afraid to accept another belief within the worldview.
Now, I don't know if you noticed, but I was careful to include that an alternative explanation must be consistent within the overall worldview. Just because someone presents an alternative explanation does not mean that it is consistent. The alternative explanation may be inconsistent- they may ignore beliefs in the worldview that would refute the proposed explanation. In this case, a true alternative explanation has not been offered. It can be defeated by showing the internal inconsistency. But, that "inconsistency" may be resolved by another belief in the worldview; in that case, we need to go back to point 3A. We can't be dogmatic about opposing worldviews just because we are outside them; we need to grant the best points and the most points. Afterall, what do those who hold the True overall worldview have to fear from a few nuggets of truth from another worldview (they live in the same world we do- they're bound to get something right)?
The Power of the Cumulative Case
Consistency Among Disciplines
The Dangers of Overstating Conclusions
Nature vs. Scripture