In interpersonal communication, people always find that people who do good deeds are always easy to suffer losses, and even suffer disasters, while bad people often take advantage, so that they get prosperous. So gradually people stop doing good deeds and act on their own private interests as the only standard. Some philosophers concluded that this standard is the natural law of human life.
Those close to cinnabar will turn red, and those close to ink will turn black is most irrelevant to the above conclusion.