We try to predict the unpredictable. Each tick of the market seduces us into thinking we can outwit volatility. Yet, again and again, it is not the system or the strategy that falters. It is the mind.The biggest losses in trading are rarely numerical. They are emotional collapses dressed up as rational decisions. Fear, greed, regret and anticipation jostle for space in a trader's head, often overwhelming the original idea. Ancient Stoic philosophy, born two millennia ago in the porticoes of Athens, offers a strikingly modern antidote.