J. U. started by insisting that my observation that "nearly all biologists accept evolution" was "patently false". When I pointed him to this evidence, he did something few creationists have the honesty to admit: that he lied.
Eventually our discussion (such as it was) focused on the incoherence of the claim "humans have free will". J. U., like a good creationist, insisted that free will was meaningful and that humans have it. I suggested that he read Wegner's book, The Illusion of Conscious Will. Not surprisingly, he refused -- creationists, as a rule, are rarely interested in learning anything. But again, he was surprisingly honest about his reasons. This is what he said: "I'm not going to read it because I don't want to waste my time reading something that can't possibly be true."
Is there any better example of the creationist mindset? They already know the truth; no amount of evidence you present can possibly change that. This is why it is, in general, a complete waste of times arguing with creationists.