Most people don't actually know what logic is. I would ask him to define logic to see where he's coming from. Because most people either don't have a definition or if they do it's different than the one the person they're talking to has. But to do that, you'll also want a definition you could explain to someone else going into asking the question.
I'll take a swing at it. I'm curious how I'll do if I just wing it.
Logic is a set of rules that can be used to form repeatable results based on given information. It's often built using one's own knowledge and experience. Logic does not require producing accurate results. Flawed logic is still logic. Logic also does not guarantee that the results are the desired results, this is sometimes described as "garbage in, garbage out".