What separates humans from animals is less distinct than we might expect. The examination of human nature not only holds interest for philosophers, but concerns all of us directly. How should humans live? If we trace our lineage in the context of life's evolution on the Earth, we find that our species is a comparatively recent phenomenon. The Earth is about four and a half billion years old. The origin of the ancestral stock of the African apes and humans, although uncertain, seems to be no earlier than thirteen million years ago. The Neanderthals, an early relative of modern human beings, are believed to have lived about 100,000 to 30,000 years ago. Although scientific investigation has not yet pinned down the moment of divergence between humans and apes, it is clear that we have a far longer history as animals than as humans.
In the course of evolution, Homo Sapiens have developed the ability to reason as this name "man the wise" indicates. Animals live predominantly according to instinct. As a result, their influence cannot exceed what is prescribed by their natures. Through our intelligence, however, humans can exercise good or bad influence far beyond what seem to be our natural limits. A shark may bite a surfer's leg dangling beneath the surface, but it cannot make a bomb capable of annihilating all life on the planet. Perhaps due to our long history as animals, we amplify—ironically through intelligence—our animalistic impulses to seek selfish pleasure and thus destroy what we fear and bring harm not only upon ourselves, but also upon many other species.
From various perspectives, Buddhism throws light on the workings of human nature. One Buddhist concept that does so is the Ten Worlds, originally described as distinct realms into which people are born according to their past actions (karma). From the lowest, they are the worlds of hell, hungry spirits, animals, asura (warlike demons from Indian mythology), human beings, heavenly beings, voice-hearers, cause-awakened ones, bodhisattvas and Buddhas. In Nichiren Daishonin's Buddhism, however, the Ten Worlds are viewed as various states of being we experience from moment to moment, rather than distinct physical realms or categories. Then Ten Worlds, therefore, may be understood as the following states: (1) Hell—intense suffering and despair, (2) Hunger—insatiable desire, (3) Animality—selfish stupidity, (4) Anger—arrogance and belligerence, (5) Humanity—temporary balance and tranquillity, (6) Heaven—passing joy and pleasure, (7) Learning, (8) Self-realization, (9) Bodhisattva—altruism, and (10) Buddhahood—supreme happiness characterized by compassion and wisdom.
Buddhism classifies those Ten Worlds into two categories. The six lower states are called "the six paths," and the four higher states "the four noble worlds." Such distinction is made because those who dwell in the six paths are controlled by their environment or physical condition; they experience any of those six states at any moment in response to changing circumstances. People of the four noble worlds, on the other hand, are self-aware, striving to improve themselves regardless of external conditions. The Daishonin succinctly explains the six paths as follows: "Rage is the world of hell, greed is that of hungry spirits, foolishness is that of animals, perversity is that of asura, joy is that of heaven, and calmness is that of human beings" (The Writings of Nichiren Daishonin, vol. 1, p. 358). Common to all six is that they are passive states. It may be said that animals like dogs and cats manifest those states whenever they have an appropriate stimulus. Those of the six paths are slaves to their desires and environment though at times they may seem carefree, doing whatever is pleasurable. Simply put, those of the six paths are trapped in the dungeon of desires and external circumstances, and have locked the gate to true happiness from the inside through ignorance of their higher potential.
On the contrary, the four noble worlds only emerge when we make deliberate efforts to develop ourselves beyond our natural tendencies. Buddhism, in this sense, defines our humanity in our active will for self-reflection and self-improvement. Regarding those four higher states, the Daishonin comments as follows: "The fact that all things in the world are transient is perfectly clear to us. Is this not because the worlds of the two vehicles are present in the human world? Even a heartless villain loves his wife and children. He too has a portion of the bodhisattva world within him. Buddhahood is the most difficult to demonstrate. But since you possess the other nine worlds, you should believe that you have Buddhahood as well" (WND-1, 358). Here "the worlds of the two vehicles" refers to the states of learning and self-realization. As people see the transience of the world around them, they come to realize the shallowness of letting their self-worth raise and fall with the ups and downs of circumstance, and seek to expand their knowledge of themselves and the universe. The Daishonin also points out that we are all capable of extending our love and care to others despite our baser instincts. Regarding the state of Buddhahood, the Daishonin urges us to overcome our disbelief and reveal this supreme state of happiness through faith. What characterizes people of the four noble worlds is their awareness of the slavish reality of the six paths and their conscious efforts to free themselves from the shackles of selfish desire and attachment.
In one sense, Shakyamuni and other Buddhist teachers expounded their teachings so that people might escape the entrapment of the six paths and pursue more humane ways of living. In early monastic Buddhism, practitioners were encouraged to establish the states of learning and self-realization. Mahayana Buddhism stressed the altruistic state of a bodhisattva. The Lotus Sutra, the supreme teaching of Mahayana Buddhism, illuminates the path of Buddhahood. In this regard, Buddhism teaches us the importance of transforming the animalistic, passive conditions of the six paths into the self-aware, humane states of the four noble worlds.
The necessity to transcend our animalistic nature is stressed not only in Buddhism, but also in many intellectual traditions of the West. For example, in medieval and Renaissance Europe, the human existence was divided into the four categories of the mineral, vegetable, sensual and rational. The man of stone is a man of despair and sloth. He exists but has no will to act; his existence is living death. The vegetable man only lives; he is a man of gluttony who eats, drinks and procreates. The sensual man, like many animals, lives and feels; he seeks pleasure and avoids pain. The rational man, unlike the previous three, lives, perceives and understands; he knows, chooses and acts. An image of the rational is a man at his book, trying to expand his awareness and understanding. As in the Buddhist concept of the Ten Worlds, Renaissance philosophy characterizes humans by their active will to challenge themselves.
In reality, however, it is easy for us to fall into the lifestyle of the six paths where we mistake pleasure for supreme happiness and fail to challenge our weaknesses. This may be the result of our long history as animals. But if we truly wish to experience the profound sense of fulfillment as human beings, we must, as taught by the wisdom of both East and West, challenge ourselves to manifest the higher states, especially those of bodhisattvas and Buddhas.
Plato quotes his teacher Socrates: "I only wish that ordinary people had an unlimited capacity for doing harm; then they might have an unlimited power for doing good, which would be a splendid thing, if it were so." The ominous first half of his wish has come true with the arrival of the nuclear age. The fulfillment of the rest of Socrates' wish, it seems, depends greatly upon how willing we are to challenge ourselves to live as humanly and humanely as possible in the twenty-first century.
Living Buddhism, July 2000, p.5