I don't know that any idea is ever really "new" although some ideas create more change than do others. I'm sure a great many people have looked at the behaviour and dynamics of systems under exogenous and endogenous loads or perturbations. There's plenty of interesting work in this area in systems theory, biology, economics, control theory, etc.What is interesting about Taleb's view is the reframing of risk and risk-affected systems. Rather than strive for systems that never create risk or volatility, he's advocating that we create systems that benefit from risk and volatility. Although the recent crisis has brought a repudiation of risk as if the creation of risk caused the problem, I think he's arguing that risk aversion is no solution. Flight-to-safety is a false refuge. In fact, risk aversion is actually a very dangerous solution.And he's right that the English language has no word for things that are the opposite of fragile. Loosely speaking, we might define:Fragile: ∂Performance(t)/∂Volatility << 0Robust: ∂Performance(t)/∂Volatility = 0Anti-Fragile: ∂Performance(t)/∂Volatility >> 0And if we are to be strictly correct, a fragile system (e.g., a crystal champagne flute) is one that performs to perfection up to some threshold level of stress and then abruptly shatters. Fragile systems do not degrade gracefully. That's what makes them so dangerous. They seem to function extremely well under some day-to-day modicum of stress and then fail catastrophically under some infinitesimal increase in that stress. Moreover this is NOT an issue of rigidity (although fragile things do tend to be rigid). An aluminum champagne flute and a crystal champagne flute are equally rigid yet the aluminum one fails by bending. Similarly, one can build glass structures that are extremely flexible and yet when they reach some critical level of stress, they still fail catastrophically. Its the hidden nonlinearity that make fragility so dangerous.The root cause of fragility of a material (e.g., glass) or a system (e.g., a bank or an economy) lies in how it handles minor imperfections with incremental loads (defects + stress). In a material such as glass, a defect + stress creates a self-amplifying growth of the defect so that local failure almost instantly leads to global failure. Although avoiding risk (e.g., "handling with care") might seem advisable, that's no solution both because defects inevitably occur and stresses inevitably overstep the threshold of failure.An anti-fragile system would have the opposite response to local defects and local extrema in stress -- it would grow stronger, not shatter. From an economic, regulatory, and organizational perspective, an anti-fragile system must have implicit or explicit mechanisms for handling (rather than avoiding) local defects and local concentrations of stress in ways that increase the system's tolerance to said defects and stress. But even more so than "tolerating" defects and stress (which is simple robustness), the anti-fragile system improves with exposure to defects and incremental stress. In other words, it learns from each defect or incremental stressor to be able to handle an every greater amount of that defect or stressor. The result is a system in which the optimum defect rate and stress volatility is greater than zero -- the system constantly pushes the limits in small local ways, handles the resultant local failures, and increases it's performance and operating range.