An Ancient Science of Nature and the Human Soul
Samkhya is a theory of nature and consciousness that is older than the Vedas. The science of self-knowledge, yoga, is rooted in Samkhya and represents the practical application of its theoretical postulates.
Much of Indian philosophy is based on concepts found in Samkhya. Samkhya is at the core of not just Indian but also world spirituality, given that it is, in fact, the first fundamental ontology: the science of being and cognition. The basis of Samkhya lies in differentiating Purusha and Prakrti, that is, the human soul and nature, respectively. It is the oldest and clearest differentiation of consciousness.