The law of perpetual increase: What you give is what you get. Happiness begets happiness, positivity begets positivity, hate begets hate & so on and so forth.
Sure I haven't submitted this 'law' for scientific or academic debate but I apply it all the same.
With this law in mind I try to surround myself with influences (both living and inanimate) that I would like to perpetually increase such as passionate people, inspirational attitude, beautiful music, peaceful places & a myriad of other examples.
“Darkness cannot drive out darkness; only light can do that. Hate cannot drive out hate; only love can do that. Hate multiplies hate, violence multiplies violence, and toughness multiplies toughness in a descending spiral of destruction….The chain reaction of evil–hate begetting hate, wars producing more wars–must be broken, or we shall be plunged into the dark abyss of annihilation.”
-Martin Luther King, Jr., Strength To Love, 1963.
Do you have any theories of your own?