The point is actually that few ideas are perfectly correct, and that it can be very helpful to analyse them carefully. Sometimes our most comfortable truths are just ordinary ideas that are particularly lively or robust – that is, they are ideas we feel strongly about. But if we honestly and courageously examine their logical relations or relationship to the evidence, we might find them wanting. At the very least, it’s a willingness to listen to arguments and facts that might contradict us; to recognise that other ideas can be reasonable, if not convincing.