That is manifested as a skepticism and dislike for basing your beliefs, arguments, and actions on external sources of information. For instance, this individual will rather trust the expertise of someone who seems to have hands-on experience, even if limited, than of someone who demonstrates to have read many books on the same subject. They will base their opinions and views on their own personal insights and be, again, skeptical of "second-hand" factual information that contradicts it. "Don't trust everything you read" is a typical sneer of this function, especially when applied to sources of information otherwise seen as neutral and reliable, such as encyclopedias and handbooks.
Another manifestation is a dislike for dealing with issues involving efficiency, productivity, and factual accuracy of statements made; statements are made according to input from other functions, not from double-checks against external facts which are seen as of lesser relevance to the issue at hand. Types with this function lack confidence in their ability to find relevant information in outside sources.