What would happen if the entire world believed in reincarnation and causality (karma and innen)? Would there be killings, and evil toward our fellow man or woman? Who would commit an atrocious act if one knew that the same act would eventually be perpetrated toward him or her? One would try to bring joy to other, so that the same joy would be placed on oneself. But what the world sees are the sufferings and inconveniences of our past actions, which they do not understand. They hopefully look forward to an afterlife, which is not certain. They see good and evil in the world and they see joy and suffering; but they do not understand the relationship.
Yes, if we did believe in reincarnation and causality, we would initially be good due to fear of the effect of our actions. But in time, we would realize the inherit benefits of being good. In the sacred book of the Heaven’s Truth Religion (Tenrikyo), God tells us that there is an immediate benefit of being good (removal of greed, arrogance, and self love) from the mind. We become spirited or joyful. We don’t need to seek drugs, alcohol, physical possessions, monetary possessions, and power to become happy. We all want to be spirited each day, and God gives us these simple instructions to do this.