I wasn’t referring to ID, but only making a general point. Thus, if I claim that a way has been discovered by which human beings can fly by flapping their arms, and people show skepticism, I can’t say: “Unless you guys can give me a rigorous proof that it’s impossible for a man to fly by flapping his arms, my claim is correct.” Skeptics aren’t required to prove a negative. I’m required to provide evidence that people can fly in that way. Otherwise, the world is justified in ignoring me.
One of the mistakes some ID people make in debate is getting suckered into trying to prove a negative. For example, some might argue that it is impossible that life could have originated by unguided chemical combinations. I think that’s a massive tactical error which puts an unnecessary burden on those who assert it. I think the onus is on the people who say, “Sure, life could have arisen by unguided chemical combinations.” It’s up to them to provide evidence that such a thing could have happened, by suggesting plausible steps, testing them, and so on. The general public is under no obligation to accept a speculation as fact. Nor is it under the obligation to prove that the speculation is impossible. The onus is on those who are convinced that life came into existence without any guidance or planning, due to chance combinations of atoms and molecules plus later chemical developments, to give a credible account of how it could have happened. If they fail to give a credible account, there is nothing “unscientific” or “ignorant” or “anti-science” in saying that the speculation has not presented convincing support, and that they withhold consent.