Over the years I've learned to be suspicious of simple solutions to difficult problems and those who assert such solutions. When trying to convey that healthy skepticism to others I tend to use the phrase "beware those who express the certainty that can only be born out of ignorance or a swindle."

The analogy I use to explain how the acquisition of knowledge leads to humility is akin to climbing. You start in a ditch and can only see a single mountain that you must ascend to be knowledgeable. Once you reach the peak of that mountain you are greeted with an entire new range of mountains that would remain hidden from you without the benefit of your newfound perspective. You may also safely assume that beyond each of those mountains lies yet another set of partially or completely obscured mountain ranges.

As Socrates said, "if I am wise it is only in that I know what I do not know."