I have a problem with the following sentence in Zhu Xi's commentary to Mencius:
非孟子造道之深,不能形容至此也
How one should translate 非 at the beginning of this passage?
From what I understand it is something like "except Mencius who reached the depths of the dao, no one could describe arriving at this [situation]. (Namely the situation Shun found himself in passage 7A16 - to which the sentence refers)
1.[非] XXX,[不能] YYY = [not having] XXX, [cannot] YYY
"非 XXX 不能" is a relative clause; "YYY" is a verb clause
Example:
[非]孟子造道之深,[不能]形容至此也= [Not having] 孟子造道之深,[cannot]形容至此也
The "非 X 不能 Y" structure is what we call "two negatives produce a positive". It's an emphatic way to say "only X can Y".
The sentence seems the author agrees with, and prises 孟子 for his insightful description or explanation of something, which can only be made by 孟子 because of his deep training and understanding on the matter. So, I would think the sentence says:
若非(if not because of)孟子's造道之深(deep training and thorough understanding of this matter),不能(it can not)形容(be described)至此也(to such an extent).
The format of this sentence is: "若不是(非)..., 就不能...", which contrast the sentence below:
非你我之力能及也 = 不是(非)你我的能力能達到(及)的.
