Stupidiy can be lacking or flawed intelligence, tendency to groupthink (trying to minimize conflict and reach consensus without critically testing, analyzing, and evaluating ideas), confirmation bias (rational thought being derailed by strong opinions or rigid beliefs which adhere to selective evidence), unwitting selfdestruction or the ability to act against one's best wishes.Modern science specifically evolved to combat confirmation bias. During scientific thought we should constantly criticize our own beliefs and assumptions (attempt to disprove hypotheses), while also using humility and extreme self-honesty to reduce our ego-based biases.
Is a fool same as stupid? I don't know... But I starkly remember this cryptic story from Chandoba which drove me nuts as a child.
Once a king had two sons, elder being studious, sincere, respectful and the younger being unruly and arrogant. Worried about their rearing, the king decides to send both to the gurukul of a distant wise sage. 6 months later, to see their progress he visits the ashram, and meets his two sons one after the other. The young one is delighted. "Father, I love this place. Studies are so easy. Guruji gave me some texts to read, they all talked about tales of foolishness, and I was able to finish them faster than anybody else. At this pace, I think I can finish all the studies within 1 year." When asked about his elder brother, he said, "He has immersed himself in studies. He takes them a bit too seriously."
When king met elder son, and asked how he was doing, he said, "Father, I have understood how much I have to learn still, to be a good king. Hence I spend all the time learning, reading books, discussing & internalizing. I think I still have long way to go. I will need 3-4 years to complete my studies."
When the king met the sage himself, he said "Your elder son is progressing well. Within 3 years, I feel he will be adept at ethics, politics and other duties of a king." "What about the younger son?", king asked. Sage paused a moment, and said, "Oh, he is too brilliant for my school. His retentive powers are superb, and so is intellect, and is already way ahead of his peers. I don't think, he has any use of my teaching. Instead of wasting his time, I suggest he return and continue his studies at home." This surprised King, but after a while, he acted as suggested. End of story.
This story drove me nuts. Was younger son a fool? Did he not realize the texts he read are talking about people like him? Can Fools be intelligent? Can fools help their being fools? Is this some uncurable disease that sage washed his hands off? So many questions... That was beauty of Chandoba. It taught us ethics with such stories .