Here's an example: some time ago I was discussing evolution with a creationist, and was asked "Can you prove it?" I responded that "prove" isn't the appropriate word, but rather scientists gather and evaluate evidence to see what position the evidence most clearly supports. He crowed in jubilation. "Then you don't have any proof!" he exclaimed.
So my response in that situation has changed. I now respond, "Yes, we have the same level of proof that sends people to death row: We've got the DNA!" That's adapted from Sean B. Carroll, author of Making of the Fittest.
With respect to the first potential response you identify,
"The power of science comes from having the ability to change our minds and admit we're wrong. If you've never admitted you're wrong, it doesn't mean you've made fewer mistakes."
Put more simply, in artificial evolution you get exactly what the fitness function you've written asks for, even when you don't know what it's actually asking for.