- Lived:
- known only from texts — a brahmin of the Gautama clan, active in the Kuru–Pañcāla country of the upper Ganges plain (roughly modern Haryana and western Uttar Pradesh); the doctrines bearing his name sit in the oldest Upaniṣadic layer, c. 8th–6th century BCE
- Field:
- philosophy — and something very like natural science, two and a half millennia before the word existed
- The Big Idea:
- Everything that exists is one substance under many names, the way all clay pots are clay — and you can demonstrate the invisible from the visible: break a fig seed, dissolve salt in water. The subtle essence you cannot see is what everything is, "and thou art it."
- In their words:
- "That which is the subtile essence, in it all that exists has its self. It is the True. It is the Self, and thou, O Śvetaketu, art it." (Chāndogya Upaniṣad 6.12, translated by Max Müller, 1879)
- If you remember one thing:
- A father in eighth-century BCE India taught his over-educated son by experiment — a split fig, a glass of salt water — and drew from those experiments the sentence Indian philosophy has been unpacking ever since: tat tvam asi, "that thou art." The same texts record, without embarrassment, that this teacher was twice out-argued, once by a king and once by his own student. That honesty is why we can trust the rest.