This is from the Internet Encyclopedia of Philosophy:
“The oracle at Delphi told Socrates’ friend Chaerephon, “no one is wiser than Socrates” (Apology 21a). Socrates explains that he was not aware of any wisdom he had, and so set out to find someone who had wisdom in order to demonstrate that the oracle was mistaken. He first went to the politicians but found them lacking wisdom. He next visited the poets and found that, though they spoke in beautiful verses, they did so through divine inspiration, not because they had wisdom of any kind. Finally, Socrates found that the craftsmen had knowledge of their own craft, but that they subsequently believed themselves to know much more than they actually did. Socrates concluded that he was better off than his fellow citizens because, while they thought they knew something and did not, he was aware of his own ignorance. The god who speaks through the oracle, he says, is truly wise, whereas human wisdom is worth little or nothing (Apology 23a).
This awareness of one’s own absence of knowledge is what is known as Socratic ignorance, and it is arguably the thing for which Socrates is most famous. Socratic ignorance is sometimes called simple ignorance, to be distinguished from the double ignorance of the citizens with whom Socrates spoke. Simple ignorance is being aware of one’s own ignorance, whereas double ignorance is not being aware of one’s ignorance while thinking that one knows. In showing many influential figures in Athens that they did not know what they thought they did, Socrates came to be despised in many circles.”
This is the starting point for all claims in this class. Assume that you do not know, even in cases in which you might feel certain that you do. If one begins with that attitude, one has the opportunity to learn something. If on the contrary one begins assured that one already knows, one is likely to remain in ignorance, and, still worse, to be doubly ignorant in Socratic terms, as in that case one does not know and one does not know that one does not know. Even to not know but to be aware that one does not know is superior to this benighted position.