The law of resonance describes how something vibrating with a certain frequency will start the same vibration in anything in its vicinity that harbours that vibration potentially. For example two similar tuning forks in close proximity, both set in positions so they can vibrate freely, if one is set to vibrate, the other will start too even if untouched. This law implies that whatever happens is more or less powerful, more or less confused by the resonances between for example what is said and body language, what is said and what is thought of, what is said and how the speaker go about the same issues in his own life etc.