delve into secret facts(/principles); delve into the abstruse (/the profundities of the unknown); search for hidden meanings; unravel mysteries ❍ ～，钩深致远。(《周易·系辞上》) Search for hidden meanings and probe into profound truths.
探赜索隐tan ze suo yin
probe into profound truth
探赜索隐tàn zé suǒ yǐn
赜：深奥；隐：秘密。探究深奥的道理，搜索隐秘的材料。search for hidden meanings, unravel mysteries, delve into the abstruse, investigate and trace the hidden things