This is a tricky matrix to understand. If you know what you don’t know, then you are either wise or a fool because of two senses of the word “know.” You are wise if you are aware of what you don’t know. For example, a product manager at a company might hire an industrial designer because he knows good design sells, but does not know how to design. You are a fool if you believe to be true something that is not, especially if there is substantial evidence to the contrary, or believe you have expertise in an area you do not.