The seven Hermetic principles (mentalism, correspondence, vibration, polarity, rhythm, cause and effect, and gender), are set out in The Kybalion, published in 1908 under the pseudonym "Three Initiates" and generally attributed to William Walker Atkinson. The book presents them as the essence of an ancient Hermetic philosophy, summed in maxims such as "as above, so below" (correspondence) and "the All is mind" (mentalism).
Each principle states a supposed universal law: that all is mental, that the pattern repeats at every level, that everything vibrates, that opposites are one in degree, that all moves in rhythm, that nothing escapes cause, and that gender is in everything.