Nightning: if you're talking in the singular, then, cause does not = effect.
But in the pluralistic sense: effect may = cause. Not the same, but another new cause. envision it in the sense of two rulers: one beneath the other. Take odd numbers as cause, even numbers as effect.
They start out equally.
But if you shift the second rule, such that its 1 is equivalent to the other's 2, then, that is how the effect of one action becomes the cause of a new action.
Edahn: waves are always in the mind; more often than not, they generate deed. Which is why karma is given not on thought, but on deeds of one's own volition.
ie, if you do not act on a cause, then there are no waves. No repercussion; according to the classical rules of karma.
Concretise it:
Hitler thinks of Aryan supremacy. But he only holds it as ideas in his head, and does not act upon it. Is there cause? Yes. But are there effects? No.
Where does effect come in? When he acted upon it and eliminated the Jews.
That effect was the Holocaust. Greek: holos = completely. kaustos = burnt.
That effect generated other causes.
Oscar Schindler, who felt the need to save as many Jews as he could, even though he was German.
Poland, left with the legacy of Auschwitz, Beltzec, Chelmno, Majdanek, amongst others: kept as memorials for the world, so the world would not forget: even though the people themselves struggle with the daily reminder of such a legacy.
Anne Frank. A diary. A young girl. The saving of an old chestnut tree. Would a tree cause such worldwide media attention, otherwise?
The Final Solution to the Jewish Problem. In its actual German: Die Endlosung der Judenfrage. The concept of genocide is articulated for the first time in the world. Spawning: genocides in Rwanda. Bosnia. Cambodia.
Causes and effects. Causes lead to effects, which become other causes.
The link is in action. If there is no deed, the cause is ended. The waves of the mind and in the world then become calm.
but ah. A question then: is the human propensity not for action? How else the concepts of revenge, justice, vendetta?
Humans. Homo sapiens. Sapiens meaning sentience. Do we truly think, or do we not merely act emotively? And thereby, effects become new causes, and the cycle goes on.