The Principle of Cause and Effect describes the philosophical
concept of causality, stating that every event is an effect and has another event as
a cause and is itself the cause of yet another effect. The principle also maintains
that there is no such thing as chance as an uncaused happening. Whatever happens,
there must be a cause for it, nothing comes from nothing. If we cannot see a cause
for an event it does not mean there is none - it merely means that the cause is
obscure and not known. There is always a continuity between what has happened in the
past, what is happening now and what will happen in the future.
This principle is most important for reading Tarot cards, when the understanding of the cards means to understand the correlations between the cause and the effect of any little hint the cards will give.
From the Kybalion:
This Principle embodies the fact that there is a Cause for every Effect; an Effect from every Cause. It explains that: 'Everything Happens according to Law'; that nothing ever 'merely happens'; that there is no such thing as Chance; that while there are various planes of Cause and Effect, the higher dominating the lower planes, still nothing ever entirely escapes the Law.
The Hermetists understand the art and methods of rising above the ordinary plane of Cause and Effect, to a certain degree, and by mentally rising to a higher plane they become Causers instead of Effects. The masses of people are carried along, obedient to environment; the wills and desires of others stronger than themselves; heredity; suggestion; and other outward causes moving them about like pawns on the Chessboard of Life.
But the Masters, rising to the plane above, dominate their moods, characters, qualities, and powers, as well as the environment surrounding them, and become Movers instead of pawns. They help to play the game of life, instead of being played and moved about by other wills and environment. They use the Principle instead of being its tools. The Masters obey the Causation of the higher planes, but they help to rule on their own plane. In this statement there is condensed a wealth of Hermetic knowledge - let him read who can.