The Buddha’s teachings are intended to lead the practitioner toward Nirvana as a way to escape being reborn into any of the Six Realms via the Wheel of Rebirth. He taught an escape from the law of Karma itself. As a privileged man who experienced sensual pleasure and luxury, and then as a self-committed ascetic who put himself through torture and self-neglect, he renounced both extremes and offered a Middle Way.
The Buddha’s incisive contributions to world philosophy hinge upon the Four Noble Truths. From the Four Noble Truths come a number of indispensable teachings. The First Noble Truth is an affirmation of the reality of suffering and its causes. The Second of the Four Noble Truths is that suffering has a cause and offers the teaching of Dependent Origination and the clinging to the Five Aggregates to explain that cause. The Third Noble Truth is that suffering can be alleviated. The Fourth Noble Truth is that the Eightfold Path offers relief from suffering.
A Buddhist accepts the three marks of existence: suffering, non-self, and impermanence. Adherence to the Buddha’s middle way between extreme physical asceticism and hedonism is the prescription for a virtuous and meaningful life. There are innate mental barriers to practicing the Buddha’s teachings, namely greed, hatred, and ignorance.
The Buddha, iconoclastic as he was, still delivered his message in terms of the prevailing philosophy of his day. For example, he offered the Four Brahmaviharas as mental factors to practice for the greater good. The term Brahmavihara refers to the dwelling place of Brahma, the supreme creator god of Brahmanical religious cosmology. In spite of this concession to his peers, he did deny the idea of self-nature, which distinguished him from the orthodox thinkers of his day.
A fifth-century philosopher handily grouped many of the Buddha’s teachings together as the Thirty-Seven Limbs of Enlightenment.