The joy of volatility

What is the opposite of fragile? That's a question that Nassim Nicholas Taleb always asks when he is talking about his book Antifragile. Audiences always respond with words like 'strong' or 'robust' or 'unbreakable'. Then Taleb asks, "What is the opposite of positive?" Obviously, people answer 'negative'. "Why didn't you say that the opposite of positive is zero? If the opposite of fragile is robust, then the opposite of positive should be zero. This usually needs further explanation from him. If, as Taleb explains, you are shipping a glass object, you normally write 'Handle Carefully' on the package. However, if you are shipping something made of iron, you won't write anything on it, because an iron object is strong and robust and unlikely to break if the package is dropped. But that's not the true opposit