"If I think a stock is a sell at $X and you think it's a buy, we trade, but clearly one person knows (or thinks they know) something that the other doesn't" Th

"If I think a stock is a sell at $X and you think it's a buy, we trade, but clearly one person knows (or thinks they know) something that the other doesn't" Theoretically, everyone who ever buys or sells could make money. They just have to be trading on different time-frames, different entry/exit strategies, and/or have different risk tolerance. I do agree with your overall point.