Much like there was a need for a new kind of system to tolerate rapid changes around it, there is now an emerging need to not just tolerate or adapt to those challenges, but evolve from them. Robust systems can handle adversity but stay the same, agile systems move and adapt rapidly, but a new kind of system - antifragile - would behave like a biological organism, actually evolving and getting stronger in response to stress and change. An excellent report from PwC about the evolution from lean and agile to antifragile.
Like the human body, whose immune system gets stronger from exposure to germs and diseases, the antifragile system improves or responds positively when shocked. While fragile systems are easily injured and suffer from volatility, antifragile systems grow stronger in response to volatility. So-called robust systems remain unchanged.