The black swan theory or theory of black swan events is a metaphor that describes an event that comes as a surprise, has a major effect, and is often inappropriately rationalized after the fact with the benefit of hindsight. The term is based on an ancient saying that presumed black swans did not exist – a saying that became reinterpreted to teach a different lesson after black swans were discovered in the wild.
黑天鹅理论，也叫黑天鹅事件理论，是一个比喻，形容一个出人意料的事件。这个事件往往产生了重大的影响，并且事后(after the fact with the benefit of hindsight)常常被错误地解构分析(inappropriately rationalized)。这个词源于口口相传(ancient saying)，古时人们一直认为黑天鹅并不存在。后来随着黑天鹅在户外(in the wild)被发现，这个传说便被赋予了时代内涵(become interpreted to teach a different lesson)。
The theory was developed by Nassim Nicholas Taleb to explain:
这个理论是由Nassim Nicholas Taleb 开创并阐释的：
- The disproportionate role of high-profile, hard-to-predict, and rare events that are beyond the realm of normal expectations in history, science, finance, and technology.
- 引人注意的(high-profile)、出乎意料的(hard to predict)稀有事件的不成比例性(disproportionate)。这些事件超出了历史、科学、金融、技术等领域的常规预期范围(realm of normal expectations)
- The non-computability of the probability of the consequential rare events using scientific methods (owing to the very nature of small probabilities).
- 使用科学方法（依靠特别小概率性质/nature）的结果罕有事件(consequential rare events)的概率的无法计算性。
- The psychological biases that blind people, both individually and collectively, to uncertainty and to a rare event's massive role in historical affairs.
- 无知的(blind)个人(individually)或群体(collectively)面对史实(historical affairs)中的不确定性(uncertainty)和罕有事件的巨大作用(massive role)产生的认知偏差(psychological biases)
Unlike the earlier and broader "black swan problem" in philosophy (i.e. the problem of induction), Taleb's "black swan theory" refers only to unexpected events of large magnitude and consequence and their dominant role in history. Such events, considered extreme outliers, collectively play vastly larger roles than regular occurrences. More technically, in the scientific monograph 'Silent Risk', Taleb mathematically defines the black swan problem as "stemming from the use of degenerate metaprobability".
不像早期更广为流传(broader)的哲学名词“黑天鹅问题”（例如，归纳问题/problem of induction），Taleb的“黑天鹅理论”只是描述重大的(large magnitude and consequence)意外事件(unexpected events)以及它们在历史上所起的主导作用(dominant role)。这些被视为异常(considered extreme outliers)的事件相比普通事件(normal occurrences)产生了更为深远的影响(collectively play vastly larger roles)。从专业的角度说(more technically)，在其科学专著(monograph)《沉默的风险》中，Taleb从数学上证明了黑天鹅问题“源于(stem from)退化元概率(degenerate metaprobability)的使用”。
