An interesting definition of karma (taken from Jainism): Karma is a matrix of very fine matter, which, imperceptible to our senses (and scientific instruments), weaves circumstances into our lives that respond to our thoughts, feelings, and actions.
The eleventh Tarot card illustrates karma. It shows the law of action and response at work that keeps the universe in balance. Tarot card 11 and 2 are closely related because 11 reduces to 2 (11 -> 1+1=2). Tarot card 2 is the Uniting Intelligence, the universal matrix so to say.