"I don't necessarily have every fact about the relative environmental value of electric cars loaded in my mind and ready to go in case I need to discuss the topic with someone. So I would be in a weak position if I simply started debating the subject, because I would feel that I didn't have the facts I needed to form a knowledgeable opinion. I know enough to know that the statement is probably wrong even if you consider the full life-cycle emissions, but I would want to double check.

If this were a debate with another engineer at work, or even a friend who was an engineer, I would assume that this person would respond to information as we have been trained to do - evaluate the source, evaluate the information, seek as much additional information as we think we need, always paying attention to the authority and expertise of the source (as well as whether it makes any sense). I would ask the person what information they based their opinion on. I would tell them that I didn't have a formed opinion on it, but I would read up, and that I would love to continue the conversation after studying the question a little for myself. Then we could just let the chips fall where they may, and may the person with the most credible data win.

On the other hand, if this were, say, a childhood friend, a person that I know well and value highly as a friend, I would be thinking fast about whether it was worth getting into it at all. His passion and love of his traditional cars would likely get in the way of a real exchange of information, and it might not be worth it to me to try to change his whole world view. I might just say, 'Mmmmmmm,' in a non-committal way, and change the subject.

If I DID want to tackle my friend's misperceptions, I would probably start by agreeing with him that considering the complete impact of a technology on the environment is a smart way to go, and then I would ask him where his information came from. As with the engineer scenario I mentioned above, I would want to pause the conversation to find out more about his sources, but when we discussed it again, I'd be trying to ask questions to find out what his real concern was. Is it really electric vehicle emissions? Or is his concern that internal combustion engines will be banned, along with racing? Or maybe it's that he doesn't feel that he could change over from racing IC engine cars to electrics. Perhaps it's wrapped up with political views that I have no prayer of changing. If I tackled this at all, I know it would be a delicate, long term project."