From its inception, Buddhism has been concerned with the questions, "Why do people suffer?" and "How can suffering be alleviated?" Many Buddhist teachings have sought to clarify the relationship between the cause and the treatment of misery. For this reason, Shakyamuni enumerates the five impurities in the "Expedient Means" chapter of the Lotus Sutra. They are as follows: impurity of the age, impurity of desire, impurity of living beings, impurity of view and impurity of life span.
Perhaps these five impurities seem like a list of "sins" as with the Ten Commandments of Christianity. But upon closer inspection, they are not so much a group of transgressions as they are, collectively, an elaboration on the relationship between a person and the environment—and on a broader scale, between a culture and a country, or even the entire populace and the world in which we live. To make sense of this, let's look at each impurity individually.
The "impurity of the age" refers to destructive and chaotic act in the social, economic and natural environments. War, for example, is an "impurity of the age" as is a terrible financial depression, or the oppression of a particular group of people. It is the visible end of the spectrum of mass unease and desperation.
The very normal needs for food, shelter, companionship and so forth—when polluted by negative tendencies such as greed, anger and ignorance—result in the "impurity of desire." There is nothing inherently wrong with wanting to eat, but when greed and ignorance temper the need for food, a person can lose their generosity or even become a thief, which can in turn leave someone else hungry. In this manner, healthy desires can become destructive and difficult to control. When one adds to the equation the terrible lack of basic needs often brought about by war, economic collapse and other "impurities of the age," this can lead to even further desperation and be the means by which greed, anger and ignorance pollute our natural and appropriate desires.
Desires, when destructive, can lead to mental and physical illness. This is the "impurity of living beings." Either directly to ourselves (psychosomatic illness, neurosis, malnutrition, etc.) or indirectly to others (diseases related to poverty and social inequality, mental disorders derived from abuse) we see the anguish caused by the "impurity of desire" translated into the "impurity of living beings" all around us.
Similar to the "impurity of desire" is the "impurity of view"—the adherence to erroneous beliefs. Misunderstandings about the interdependence of life (the shared causal connection between all people) are particularly problematic. This is because such beliefs promote the mistaken concept that a person is isolated and one's actions have no relation to the lives of others, or conversely that one has inordinate power and can "fix" or "control" another human being. Rooted in warped desires worsened by mental or physical imbalance, the "impurity of view" can become a philosophy of hate, senseless destruction and violence.
Lastly, the "impurity of life span" describes a life shortened or distorted because of the negative effects of the other impurities. Every day people die young because of war, starvation, crime and other dangerous situations. But the "impurity of life span" can also be interpreted as lives nullified, or rendered joyless and unrewarding; lives, in other words, that don't seem to be worth living. Such deadened, soulless feelings can occur at any age.
Taken all together, it's clear that the five impurities are neither a list nor a chain, but a loop, a vicious cycle. Referring to this cycle, Shakyamuni says, "Shariputra, when the age is impure and the times are chaotic, then the defilements of living beings are grave, they are greedy and jealous and put down roots that are not good" (LS2, 32). One impurity leads easily to the next and creates a seemingly endless repetition of sorrow.
It's important to remember, however, that the cumulative effect of a person's causes, or karma, is not solely a negative thing. Karma is a law, like gravity, not a judge doling out punishment. Because the cycle of the five impurities works in one direction, it must logically work in the other direction as well. In "On Establishing the Correct Teaching for the Peace of the Land," Nichiren Daishonin writes, "Therefore you must quickly reform the tenets that you hold in your heart and embrace the one true vehicle...If you do so, then the threefold world will become the Buddha land..." (The Writings of Nichiren Daishonin, p. 25). If the five impurities weren't reversible, the Daishonin would never have said that.
As a very simple example, the prevention of a war—or better still, the establishment of peaceful international relationships—can save many lives and lead to an increase in trade, jobs and so forth by which we can feed ourselves and our families. When such needs are appropriately met, mental strife and many illnesses are less common and people are more likely to lead long, healthy lives. This is, of course, a simple illustration.
Though war, theft, oppression and the like can bring about brief periods of wealth and security for some, they are unstable acts incapable of establishing any long-term prosperity. In the end, such acts merely lead back to the cycle of suffering. Nonviolent activities, inspired by mutual respect, are far more likely to bring about long-lasting value.
Living Buddhism, July 2001, p. 6