
A: I would like to answer this by describing the three types of persons who practice Buddhism. Generally speaking, from the smallest insect on up to the most intelligent human being, there is agreement: all want happiness and all wish to avoid suffering. The majority of human beings do not understand what the cause of suffering is, or what the cause of happiness, but in the teachings of Buddhism and in their practice, you will find the answers to these questions.
Q: What are the causes of suffering and happiness?
A: The Ratnavali of Nagarjuna says, “Every action arising from desire, aversion and ignorance produces suffering: every action arising from the absence of desire, aversion and ignorance produces happiness.”
Now, as I said, there are three kinds of people. Like all other beings, the lowest person wants happiness and wants neither suffering nor rebirth in the lower realms of existence, so he practices Buddhism to create the causes of rebirth in the human realm or in the heavenly realms of the gods. He does not have the power or the courage to leave Worldly Existence completely. He only wants the best parts of Worldly Existence, he wants to avoid he worst parts, and that is why he practices the Buddhist religion: in order to get a higher rebirth.
Now the middling sort of people understands that the whole of Worldly Existence, no matter where one is born, is suffering by its nature, just as fire is hot by its nature. He wants to get out of it altogether and attain Nirvana, the state that is entirely away from suffering.
The highest person realizes that, just as he himself does not want to suffer, and does want happiness, so also do all living beings have the same fears and wishes. He knows that, since we have been born again and again from beginningless time in Worldly Existence, there is not a single sentient being who has not been our mother and father at one time or another. Since we are that close to all sentient beings, the best person is one who practices Buddhism in order to remove all these countless beings from suffering.