The core philosophy of the SGI can be summed up by the concept of "human revolution." This is the idea that the self-motivated inner change of a single individual positively affects the larger web of life and results in the rejuvenation of human society. The SGI movement has its roots in the life-affirming philosophy of Nichiren, a Buddhist monk who lived in 13th-century Japan. Nichiren felt passionately that Buddhism should enable people living in the real world and facing real problems to become empowered and change their lives for the better. Nichiren Buddhism stresses the profound connection between one's own happiness and the happiness of others.

The greatest personal satisfaction and fulfillment in life is realized by working for the happiness of others. Nichiren's teachings assert that each individual, regardless of gender, ethnicity, capacity or social standing, has the power to overcome life's inevitable challenges, to develop a life of great value and creativity and to positively influence their community, society and the world.

Nichiren's philosophy originates in the teaching of Shakyamuni, the historical founder of Buddhism who lived in India some 2,500 years ago. Nichiren discovered that the Lotus Sutra contains the heart of Buddhist teachings and the truth to which Shakyamuni was awakened. This sutra reveals that a universal principle, the Buddha nature, is inherent in all life. It affirms that all people are capable of manifesting the state of enlightenment.