just TT will do This all is well and good and quite scholarly, but coming back to the departure point of this whole text: 'knowing where to stop' is a gross mistranslation. What that formulaic expression really means is 'to stop knowledge'. How big is the rift between the former and the latter is up to you to judge;).
Ah, and isn't this the fun of translating these things!
To say it means "to stop knowledge" could also superimpose some limits on the meaning.
The way of great learning consists in manifesting one's bright virtue, consists in loving the people, consists in stopping in perfect goodness."
The second phrase here is also interesting in it's plurality of potential meanings.
在明明德 is very open for a number of ways to understand it, since ming can mean understanding, brightness, illumination, etc. So "The way of great learning consists in clearly understanding virtue" or "consists in brightly illuminating virtue" or simply "consists in brilliant/radiant virtue."
Consists in loving (all) people. 在Consists in 止stopping 於after 至reaching/attaining 善righteous goodness
I'd say stopping, here, means simply to have contentment in righteous goodness. This could include to stop trying to "figure everything out," but could also mean: stop trying to reach for further "goodness" beyond the radiant virtue of having love for "every walk of people." Be content in/with this radiant virtue and you will know stability, tranquility, and ease; thereby, all under heaven will be sustained in it's harmonious relationships of yin and yang.
There is some very obvious crossover of Daoist-Confucian influence in this text.
We might look for a literal linear English meaning, but I think the writers often knew that their words had meaning beyond what was written.