Ordinary people or non-Buddhist practitioners possessing some psychic powers, or even arhats, would not know their intricate workings thoroughly. During the time of the Buddha, there were many non-Buddhist practitioners in India who, with their clairvoyance, saw people who were virtuous all their lives take rebirth in the hell, hungry ghost, or animal realms instead. They asked, “If cause and effect is truly infallible, why would virtuous people not end up well?” Hence, they viewed the idea of cause and effect as pure nonsense.
[Excerpt from Luminous Wisdom Book Series ~ The Right View : On Cause and Effect]