Philosophy has been a part of Indian culture since the days of the Vedas.
In fact, India is arguably the pioneer of systematized philosophical thought.
It has inspired innumerable people, who have referenced it in their works.
It would be great to have a stamp set of 6, each for one school of Indian Philosophy:
  1. Samkhya
  2. Yoga
  3. Vaishesika
  4. Nyaya
  5. Purva Mimansa
  6. Vedanta