Hofstadter has written a lot about the question of what it means to "really understand a language", and the related more relevant question of what it means to translate from one language to another. Several of his essays in "Metamagical Themas" in the 1980s covered those topics, and they are quite interesting.
He gives an example "Mary was sick yesterday", with different levels of 'understanding'. Call it "sentence M" (quoting from https://archive.org/stream/MetamagicalThemas/Metamagical%20T... , including apparent typos)
> 1. Sentence M contains twenty characters.
> 2. Sentence M contains four English words.
> 3. Sentence M contains one proper noun, one verb, one one adverb, in that order.
> 4. Sentence M contains one human's name, one linking verb, one adjective describing a potential health state of a living being, and one temporal adverb, in that order.
> 5. The subject of Sentence M is a pointer to an individual named 'Mary', the predicate is an ascription of ill health to the individual so indicated, on the day preceding the statement's utterance.
> 6. Sentence M asserts that the health of an individual named 'Mary' was not good the day before today.
> 7. Sentence M says that Mary was sick yesterday and
> Just where is the boundary line that says, "You can't do that much processing!"? A machine that could go as far as version 7 would have actually understood-at least in some rudimentary sense-the content of Sentence M.
Elsewhere in the same book he (like in this Atlantic essay) talks about the problems of translating gender across languages.
I think it was in Godel, Escher, Bach where he talks about the problem of translating a line from Russian, along the line of "He lived on B____ street." It's possible from the story, which takes place in a real city, to figure out which street that was. Let's say it was "Main Street". Does the English translation keep the original Russian word and initial? Does it translate to "Main Street" and replace the "B" with an "M"?
Or consider his book "Le Ton beau de Marot: In Praise of the Music of Language", which contains 88 different translations of a 16th-century French poem.
I think it would be difficult to incorporate all of those thousands of pages of writing on the topic into a single essay for a lay public magazine, and that your expectations are too high.
While it's true that "good" is subjective, this is a solved problem in the Turing test or Chinese room sense. We judge professional translators, like those who work at the UN. We judge students learning a foreign language. There's no reason to believe that we can't apply similar techniques to judge machine translation.
Indeed, he gives many concrete examples of a minimum level of translation competency which should be expected for a good-enough system.