Dad of a Mormon wrote:Let me provide an example of a valid use of "no evidence for is not evidence against".
When Charles Darwin wrote "The Origin of Species", he freely admitted that at the time, there wasn't any fossil evidence to support it. He predicted, correctly, that we would find more evidence in the future, and that if we didn't, his theory was in trouble. Would it be fair to say that at the time that he wrote the book, the lack of fossil evidence amounted to evidence against evolution? That is what is meant by saying "no evidence for is not evidence against". At the time, the fossil record was so small that we wouldn't expect it to provide evidence for evolution, but that fact alone (the fact that the fossil record didn't provide evidence for) is not the same as saying that the fossil record provided evidence against evolution.
(emphasis added)
Thanks.
Yes, it
is fair to day that the lack of fossil evidence
did amount to evidence against evolution. There was, however,
other evidence that argued for evolution. Darwin wasn't looking at all of the facts and saying there was no evidence of any kind. He had plenty of non-fossil evidence of other kinds.
As far as proof from the fossil record went, though, Darwin recognized the lack of evidence. He knew that "no evidence for
is evidence against" when he concluded (as you say), "that if we didn't [find fossils], his theory was in trouble."
Your mileage may vary.