We know from influenza that a new epidemic can suddenly appear just as an older one is fading, if a new form of the virus appears, or if some environmental factor increases the contagion rate. Similarly, a new speculative bubble can appear anywhere if a new story about the economy appears, and if it has enough narrative strength to spark a new contagion of investor thinking.
更准确的做法是将这些发作称为投机传染病。从流感中我们知道，新的传染病可以在旧传染病正在消失时突然爆发，如果新的病毒种类出现的话，或者如果某些环境因素提高了传染率的话。类似地，一个新的投机泡沫可以随时出现，如果关于经济的新故事出现，且故事性足够强以至于投资者被新思维传染的话。