What is the meaning of life? What are the great unseen powers behind the universe? How did life on earth originate? What is the moral way of life? The consideration of these mighty problems did not begin with modern philosophy, nor did it begin with medieval and ancient philosophies—the serious and thoughtful among the prehistory and pre-philosophy men, between 3000 years and 5000 years ago, betook on themselves to quest for the answers. As they could not find the convincing answers, these fundamental questions got passed from generation to generation and finally they fell into the lap of Ancient Philosophy, which was born in a remarkable period of philosophical achievement, between the seventh and fifth centuries B.C.E., when there was rise of the first philosophers of humanity in different parts of the world—Pythagoras, Thales, Parmenides, and Heraclitus in Ancient Greece; Buddhism, Jainism, and schools like Nyaya, Vaisheshika, Samkhya, Yoga, Mīmāṃsā and Vedanta in India; Zoroastrianism in Iran; and Taoism and Confucianism in China.
The Śvetāśvatara Upaniṣad, which is clearly a prehistory and pre-philosophy text, begins with these questions (hymn 1.1; translation by Valerie Roebuck):
Om. Scholars of brahman say:
What is the cause—brahman? From what were we born?
By what do we live? And on what are we based?
Ruled by what do we follow our course
In joys and their opposite, you knowers of brahman?