Yoga philosophy accepts Samkhya's theory of the three gunas - sattva, rajas and tamas - present in every living being. Sattva represents harmony and kindness; rajas represents passion and activity; and tamas represents darkness, destruction and chaos. Although present in every living being, the three gunas are found in different proportions. The theory of the three gunas is a base for yoga philosophy of the mind. Yoga philosophy believes that purusha is sattva and prakriti is tamas.
From the ethical principles of yamas and niyamas, yamas describe the values that should be avoided, such as stealing, lying or violence, while niyamas outline the values that should be followed, such as purity, self-study and contemplation of God.
Yoga philosophy is well described in "The Yoga Sutras of Patanjali," where he outlines the eight limbs, or stages, that one should follow to reach moksha. The eight limbs include the yamas and niyamas, asanas (physical practice), pranayama (breathing exercises), pratyahara (withdrawal), dharana (concentration), dhyana (meditation) and samadhi (union with God).