The term 'Tattva' is derived from the Sanskrit root 'tattvam', which means 'principle' or 'element'.

In Samkhya philosophy, there are 25 Tattvas, which are classified into two categories: the Prakriti (nature) and the Purusha (consciousness).

The Prakriti is the creative principle in Samkhya philosophy, and its primary function is to create the universe through the process of evolution.

The Prakriti is composed of three Gunas: Sattva (goodness), Rajas (passion), and Tamas (darkness). These Gunas are responsible for the creation and manifestation of the universe.

The Purusha is the highest principle in Samkhya philosophy, and it represents pure consciousness. It is the unchanging and eternal witness of the Prakriti and its evolutes.

In Samkhya philosophy, the Purusha and the Prakriti are considered to be two aspects of the same reality. They are interdependent and mutually complementary.

The goal of Samkhya philosophy is to achieve liberation (moksha) from the cycle of birth and rebirth. This is achieved through the realization of the true nature of the Purusha and the Prakriti.

The concept of Tattvas is primarily associated with the Samkhya school of Indian philosophy, which is known for its dualistic metaphysics.

The process of evolution of the Prakriti in Samkhya philosophy is referred to as Prakriti-vikara, which means 'transformation of nature'.

The first evolute of the Prakriti in Samkhya philosophy is Mahat, also known as the cosmic intellect or universal consciousness.

Buddhi, also known as the intellect, is responsible for discrimination between right and wrong, and it helps in decision-making.

Ahamkara, also known as the ego, is responsible for the sense of 'I' or individuality and is considered a product of the Prakriti.

Manas, also known as the mind, coordinates the activities of the senses and helps in the perception of objects.

Air is considered the subtlest of the five elements in Samkhya philosophy due to its pervasive and intangible nature.

Samya-avastha refers to the state of equilibrium of the three Gunas, where they are in perfect balance and harmony.