If you know all there is to know about something then you have complete and total control over it. Example is Ursula Le Guin's Wizard of Earthsea, traditional demonology etc. There are certain words that are able to change and influence the inner and outer reality of those saying them. The power is said to lie in the sounds that compose the words. Birds feathers stuck to your broom might make it fly etc.
Emphasis is on objects or people that have been in physical contact.
An example of the combination of the above 2 laws would be a voodoo curse of someone. Bonewits states that the Laws of Association are the most commonly used. An example of this in a FRP context is avatars, priests etc. of a god. When it is only a temporary identification this is possession. The Law of Union of Opposites.