What are some quotes on stupidity?

Here are some notable quotes on the theme of stupidity, gathered from various sources:

On the Danger and Prevalence of Stupidity

• "Nothing in the world is more dangerous than sincere ignorance and conscientious stupidity."1
• "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."1
• "Stupidity is far more dangerous than evil, for evil takes a break from time to time, stupidity does not."1
• "Evil isn’t the real threat to the world. Stupid is just as destructive as Evil, maybe more so, and it’s a hell of a lot more common."2

On the Nature of Stupidity

• "Stupidity consists in wanting to reach conclusions. We are a thread, and we want to know the whole cloth."1
• "The difference between stupidity and genius is that genius has its limits."1
• "Real stupidity beats artificial intelligence every time."1
• "The more stupid one is, the closer one is to reality. The more stupid one is, the clearer one is. Stupidity is brief and artless, while intelligence squirms and hides itself."2

On Interacting with Stupid People

• "Never argue with stupid people, they will drag you down to their level and then beat you with experience."1
• "Talk sense to a fool and he calls you foolish."12
• "Sometimes I wonder whether the world is being run by smart people who are putting us on or by imbeciles who really mean it."2

On the Consequences and Observations

• "We are all born ignorant, but one must work hard to remain stupid."1
• "Life is tough, but it's tougher when you're stupid."1
• "You are not entitled to your opinion. You are entitled to your informed opinion. No one is entitled to be ignorant."2
• "Whenever a man does a thoroughly stupid thing, it is always from the noblest motives."2

On Collective and Organizational Stupidity

• "Albrecht's Law - Intelligent people, when assembled into an organization, will tend toward collective stupidity."1
• "Never underestimate the power of stupid people in large groups."1

These quotes highlight various perspectives on stupidity, ranging from its dangers and prevalence to its nature and the consequences of interacting with it.