From The Upanishads

Actually, they are rather plain and direct. They do not construct any complex system of ideas and beliefs. Nor do they build up any elaborate picture of the world. Instead, in some what brief and uncompromising language, they ask what is plainly and simply true: beneath all the complications of our uncertain beliefs.

This sceptical questioning was their traditional difficulty. It went against the habits of faith and obedience upon which traditional society depended.

As a result, the Upanishad...