Rather than do all the things I should be doing today, I decided to nerd out on one of the idioms in this week's RealTime Mandarin.

And it turns out it's procrastination gold!

The idiom:

"Unfathomable" (深不可测 shēn bù kě cè)

Literally: so deep it cannot be measured.

It's one of those idioms which makes total sense by simply understanding the characters. It could easily be a modern expression.

But it's old. Very old.

The phrase first appears in the Wenzi (文子), a Daoist classic from the Warring States period (475–221 BCE), in the chapter "Origin of the Dao" (道原):

"The Dao: too high to reach its peak, too deep to fathom."

夫道者，高不可极，深不可测

Here it described the ineffable nature of the Dao itself — something beyond human measurement or understanding.

The phrase kept travelling through time:

• Three Kingdoms period (220–280 CE) writer Bian Lan (卞兰) used it in verse.

• Ming Dynasty (1368–1644) writer Yuan Hongdao (袁宏道) applied it literally — describing a quarry pool so dark it looked like ink, its depth impossible to gauge.

• By modern Chinese it had shifted to mean "unfathomable" — describing a situation, or a person that can't be worked out

And right now it's being used to describe the hidden risks of AI.

Technologies whose true capabilities nobody can fully see the bottom of.

From the Dao, to a Ming Dynasty quarry, to artificial intelligence.

Some phrases just keep finding new depths.

Example:

Getting swept up in this tech craze carries risks that are only beginning to be understood. 盲目卷入技术的狂奔，背后的风险可能深不可测。

Anyway....

Back to all those boring things I really should be doing...