In a recent Bloomberg article, columnist Barry Ritholtz references a provocative tweetstorm by famed investor James O’Shaughnessy regarding “investor ignorance.”

“The post, as regular readers know,” writes Ritholtz, “was about one of my favorite subjects. To be more precise, it was about our own lack of understand of our own lack of understanding.” O’Shaughnessy’s message centers on how important it is for investors to understand what they don’t know, starting with how the market will perform now or in the future. In the tweets, writes Ritholtz, O’Shaughnessy “notes what the probabilities are—stocks do tend to rise over time—but then says he can’t say with any degree  of certainty if stocks will indeed be higher a decade from now.”

Ritholtz argues that most people “don’t even try to envision what they don’t know,” adding that the human mind’s propensity to create and believe conspiracy theories is problematic: “indiscriminately plastering over the ‘intellectual blind spots’ leads to terrible outcomes in markets. Our lack of awareness of our ignorance may be the enabling cognitive bias that leads to all other investment errors.”

The final tweet in O’Shaughnessy’s thread states, “history has taught us that the majority of things we currently believe are wrong.” Ritholtz comments that the ability of investors to admit the possibility of “not knowing something, recognizing how much we are ignorant of, is the first step toward preventing the kinds of overconfidence and assumption of omniscience that is so damaging  to investors.”