Yoga Sutra 1.7

प्रत्यक्षानुमानाअगमाः प्रमाणानि ॥७॥

pratyakṣa-anumāna-āgamāḥ pramāṇāni ॥7॥

1. pratyakṣa: direct cognition, sense evidence
2. anumāna: inference
3. āgamāḥ: testimony from scholars in form of documentation, revelation
4. pramāṇāni: the sources of right knowledge

Direct cognition, inference and testimony are the sources of knowledge.

Pramana - sources of right knowledge: Generaly the mind perceives both right and wrong knowledge. This sutra tells us that these are the sources we can refer to get the right knowledge. They are sense evidence, inference and testimony.

Pratyaksha Pramana or Sense evidence is when you see something with your own eyes or hear something with your own ears, or witness something with your own presence.

Anumana or inference is based on sound reasoning, when you know out of your experience, and logic which can not go wrong. For example when you see smoke, you know there is fire.

Agama or testimony is reliable sources which is either documented or heard by people you can trust. But mostly in written forms, i.e. scriptures. Also in yoga, the authority is called a guru, a real guru regarded by thousands across the globe. For example; Swami Vivekananda, B.K.S. Iyengar.

References

• Four Chapters on Freedom by Swami Satyananda Saraswati, published in 1976.