だけ is frequently presented as meaning "only", "just", "merely", "no more than", as in:
最近は、漢字だけ勉強している。
Lately, I've only been studying kanji.
But it apparently has a secondary meaning which means the complete opposite (as far as I can tell), as in:
あれだけ勉強すれば、合格するのも当然です。
If you'll study to that extent, passing is only natural.
Here だけ seems to resemble the meaning of ほど.
Question: Is there any theoretical or intuitive explanation as to why 丈 encodes these two opposite meanings, into one? Or perhaps way of translating だけ that unifies these two meanings, somehow?