In Samkhya philosophy, Purusha is the eternal, conscious and pure spirit, while Prakriti is the eternal, unconscious and material world. Purusha is considered to be the ultimate reality, while Prakriti is the cause of all material existence. The role of Purusha in Samkhya philosophy is crucial as it is the driving force behind all creation and the ultimate goal of human existence.

Purusha is seen as the witness and observer of Prakriti. It is the pure consciousness that remains unchanging and unaffected by the material world. It is the source of all knowledge and the ultimate source of liberation. According to Samkhya philosophy, the purpose of human life is to attain liberation from the cycle of birth and death, and this can only be achieved by realizing the true nature of Purusha.

One of the main roles of Purusha is to be the cause of the manifestation of Prakriti. It is the catalyst that sets the material world in motion. Purusha is the source of all energy and consciousness, while Prakriti is the source of all matter and material objects. The interaction between Purusha and Prakriti is what gives rise to the entire universe.

Another important role of Purusha is to be the knower or the seer. It is through the consciousness of Purusha that we are able to experience the material world and gain knowledge. Without the presence of Purusha, Prakriti would be inert and lifeless. Purusha is the one that gives meaning and purpose to the material world and allows us to understand and make sense of our experiences.

In Samkhya philosophy, the ultimate goal is to achieve liberation from the cycle of birth and death and merge with Purusha. This is known as kaivalya or ultimate isolation. It is believed that by realizing the true nature of Purusha and detaching oneself from the material world, one can attain ultimate peace and freedom from suffering.

In conclusion, Purusha plays a crucial role in Samkhya philosophy as the ultimate reality, the cause of all creation, the knower of all experiences, and the ultimate goal of human existence. It is through the understanding and realization of Purusha that one can attain liberation and ultimate peace.