Nido Aru Koto wa Sando Aru (二度あることは三度ある - Things Come in Threes)

Nido Aru Koto wa Sando Aru

Yesterday, I introduced you to the proverb, 'sandome no shōjiki' (三度目の正直), which means that the third time is the charm.

Actually, there is another proverb, 'nido aru koto wa sando aru' (二度あることは三度ある), which has the opposite meaning of that.

'Nido' (二度) means "twice," 'aru' (ある) means "to happen," 'sando' (三度) means "three times," so the literal meaning of this proverb is that what has happened twice will happen three times.

In fact, according to Bayes' theorem, the probability that what has happened twice happens again is higher than the probability that something happens only on the third time.

二度あることは三度ある

昨日は、一度や二度失敗しても、三度目で物事がうまくいくことを意味する「三度目の正直」ということわざを紹介しました。

実はこのことわざと反対の意味を持つことわざに、「二度あることは三度ある」があります。

「二度」は "twice," 「ある」は "to happen," 「三度」は "three times" を意味するので、このことわざの意味は "What has happened twice will occur three times" となります。

実際、ベイズの定理によると、三度目で成功する確率より、二回起こったことがもう一度起こる確率のほうが高いようです。