What are some key principles of Indian philosophy, as articulated in texts like the Upanishads and Bhagavad Gita?

Indian philosophy encompasses diverse schools of thought, including Vedanta, Samkhya, Yoga, and Nyaya. Key principles include the concept of Brahman (ultimate reality), Atman (self), karma (action), dharma (duty), moksha (liberation), and the paths to spiritual realization through knowledge (jnana), devotion (bhakti), and action (karma).