How to validate the existence of causality ? The Buddha once said that it is not so easy for an ordinary person to prove the existence of cause and effect, but not impossible. Buddhism holds the doctrine of dependent arising of all phenomena or compounded phenomena. What is dependent arising? It means that cause begets effect. All phenomena are the manifestations of dependent arising, the results of conditioned genesis. Suppose a person killed an animal. It caused great harm to that animal. How can there be no consequence for the person who had committed such grave karma? Like casually throwing a seed into the moist and warm soil., it will germinate on its own with no tending required. By the same token, in the phenomenal world, every cause must bear its own fruit with no exception. 

~Depicted from From Believers to Bodhisattvas