611-547 BC Anaximander regards the "boundless" or "infinite" as the true nature of reality. He writes "On Nature."

604-531 BC Lao Tse.

600? BC Anaximandros is generally acknowledged to be the first on record to articulate a theory of evolution.

588-524 BC Anaximenes claims air is the true basic substance of reality.

572-497 BC Pythagoras posits the concept of number (mathematics) as the ultimate principal of reality. He teaches a distinction between body and mind and the immortality of the soul. (Believed to have coined the word "philosophy.î) He spends time in Egypt, absorbing ideas about past lives. His ideas are heavily influenced by Eastern religion and are passed on to Plato. He is also believed to stress the idea that the brain is the physical organ of man's intellect and location of mental illness. His pupils dissect animal brains. He also considers geometry, arithmetic and music as the most fundamental types of knowledge. He is one of the first philosophers on record to devise categories of knowledge.

563-483 BC Siddhartha Gautama ("Buddha") develops a means of meditation and ethical conduct whereby an individual confronts his past and purges himself of suffering and evil in this and previous lives.