> While writing the book I spent a lot of time searching for that comment so that I could credit/thank the author, but never found it.

Sounds like a job for the community! Maybe someone will track it down...

Edit: I tried something like https://hn.algolia.com/?dateEnd=1577836800&dateRange=custom&... (note the custom date range) but didn't find anything that quite matches your description.

z2 3 days ago | parent | next [-]

This was from 2017, and it made such an impression on me that I could find it on my first search attempt!

	▲	ontouchstart 3 days ago \| parent [-]
		“… machine learning everything that focuses on dealing with problems with a complex structure and low noise, and statistics everything that focuses on dealing with problems with a large amount of noise.”