Buddhist teachings which are conveyed secretly or implicitly and are held to be beyond the understanding of an ordinary person. It was founded on the principle that the two aspects of Buddha—the unchanging cosmic principle and the active, physical manifestation of Buddha in the natural world—are one and the same and cannot be known verbally. One method for comprehension, therefore, is through visual representation and symbolism. The practitioners of Esoteric Buddhism chant mantras, form symbolic positions with their hands ("mudras") and train in other types of mystical arts.