The phrase is documented in modern usage rather than classical sources —
秦牧 (Qín Mù, 1919-1992), in his essay 《
天坛幻想录》(Reveries at the Temple of Heaven), wrote: '
神秘只是欺骗或者愚昧无知的代名词而已' ('mystery is just a synonym for deception or benighted ignorance'). Today it is a stock four-character expression rather than a classical
成语.