In Samkhya philosophy there are three guṇas(Qualities):tamas guṇa, sattva guṇa, and rajas guṇa. These categories have become a common means of categorizing behavior and natural phenomena in Hindu philosophy, and also in Ayurvedic medicine, as a system to assess conditions and diets. Guṇa is the tendency of the mind and not the state. For instance, sattva guṇa is that force which tends to bring the mind to purity but is not purity itself. Similarly rajas guṇa is that force which tends to bring the mind to perform some action but is not action itself.