We do know why, it's because death 死 and four 四 have the same pronunciation sǐ in Chinese (and shi in Japanese).
nantsuu
joined 1 year ago
I don't think there have been many major breakthroughs in murdered people's rights since murder laws were written.
Every language has homophones. Even before tones were created, sometimes there are just coincidences. As far as I know, there's nothing to suggest that the number four and death are inherently related in some way. No one is suggesting that knead and need are related even though they sound the same, and lead (the act of leading) and lead (the metal) may happen to share a spelling but they're still completely different words.