Dealing with the paradox of confident ignorance

Charles Darwin once said: "Ignorance more frequently begets confidence than does knowledge." This sounds like a strange idea. Is it true that confidence sometimes signals ignorance? Is it true that people who are very confident about their opinions may actually be more ignorant than people who are less confident? If it is true, it might lead to a paradoxical prescription: if you feel very confident you are right about a topic you may not know enough about it. Is there evidence that confidence and ignorance may go hand in hand? Yes, a new study by Philip Fernbach et al. does provide some evidence:
Political Extremism Is Supported by an Illusion of UnderstandingPhilip M. Fernbach, Todd Rogers, Craig R. Fox, & Steven A. Sloman 
Abstract: People often hold extreme political attitudes about complex policies. We hypothesized that people typically know less about such policies than they think they do (the illusion of explanatory depth) and that polarized attitudes are enabled by simplistic causal models. Asking people to explain policies in detail both undermined the illusion of explanatory depth and led to attitudes that were more moderate (Experiments 1 and 2). Although these effects occurred when people were asked to generate a mechanistic explanation, they did not occur when people were instead asked to enumerate reasons for their policy preferences (Experiment 2). Finally, generating mechanistic explanations reduced donations to relevant political advocacy groups (Experiment 3). The evidence suggests that people’s mistaken sense that they understand the causal processes underlying policies contributes to political polarization.
What might this mean? When disagreeing with someone who is very confident about his point of view, it may work counter-productively to argue directly against his views. After all, the person is very confident about being right. In other words, he is ignorant about his ignorance. By asking questions about why he beliefs what he beliefs you may help him discover that he is not so knowledgeable about the topic as he thought he was.

When you feel very confident about something yourself, perhaps it is wise to ask yourself the same question: on what do I base my confidence exactly? How could I explain in detail what I know about the topic?