Samkhya is a philosophical school of thought that originated in ancient India. It is based on the concept of dualistic realism, which posits the existence of two fundamental entities - Purusha (spirit) and Prakriti (matter). The main principles of Samkhya philosophy revolve around these two entities and their relationship to each other.

1. Purusha: According to Samkhya, Purusha is the pure consciousness or spirit that is eternal, unchanging, and infinite. It is the source of all intelligence, awareness, and consciousness. Purusha is considered to be the ultimate reality and is separate from the material world.

2. Prakriti: Prakriti is the material world, which is made up of three gunas or qualities - Sattva (purity), Rajas (activity), and Tamas (inertia). These gunas are in a constant state of flux and are responsible for the diversity and constant change in the material world. Prakriti is considered to be the cause of all physical and mental phenomena.

3. Dualism: The main principle of Samkhya philosophy is the dualistic relationship between Purusha and Prakriti. They are seen as two distinct and independent entities, with Purusha being the observer and Prakriti being the observed. The interaction between the two is what leads to the creation and functioning of the universe.

4. Realism: Samkhya is a form of realism as it believes in the existence of a material world that is independent of human perception. Prakriti is seen as the material cause of the universe, and its existence is not dependent on human consciousness.

5. Evolution: According to Samkhya, the universe is in a constant state of evolution, with Prakriti undergoing various transformations to manifest the physical world. This evolution is driven by the interaction between Purusha and the three gunas of Prakriti.

6. Liberation: The ultimate goal of Samkhya philosophy is to attain liberation or moksha by realizing the true nature of Purusha and detaching oneself from the material world. This is achieved through self-knowledge and the cessation of the identification of the self with the material world.

In conclusion, the main principles of Samkhya philosophy revolve around the dualistic relationship between Purusha and Prakriti, the existence of a material world, and the goal of attaining liberation through self-realization. This philosophy provides a comprehensive understanding of the universe and the human experience, making it a significant contribution to the Indian philosophical tradition.