MOkshasaadhanam (Means of Liberation) – 21

‘KaraNa’ is an instrument of valid knowledge.
Pramaa’ is valid knowledge. (pramaa karaNam pramaaNam) . This is opposed to false knowledge such as an illusion.
‘Smrithi’ is a valid knowledge that is already known.

‘PramaaNam’ would mean that knowledge which has for it an object that is not already known and is not contradicted by experience.

Sometimes ‘smrithi’ is included in ‘pramaanam’ which would then mean that knowledge which has for its object a knowledge that is not contradicted.

There are six pramanas and they are:
Prathyaksham (Perception)
Anumanam (Inference)
Upamanam (Comparison)
Agama (Verbal testimony)
Arthapathi (presumption)
anupalabdhi (non-apprehension)

As you might have known, there are six different philosophies called Dharshanas.
They are:
Samkhya - is the oldest of the orthodox philosophical systems in Hinduism.
Yoga - is considered by some to have arisen from the Samkhya philosophy.
Nyaya – a school of philosophical speculation based on texts called the Nyaya Sutras.
Vaisheshika - this system postulates an atomic pluralism.
Purva Mimamsa – this school's most valuable contribution to Hinduism was its formulation of the rules of Vedic interpretation.
Vedanta - also known as the Uttara Mimamsa school, concentrates on the philosophical teachings of the Upanishads.

There are differences among the various schools on what constitute pramaana. They are given below

Charvakas – Only Prathyaksham
Buddhists and Vaiseshikas – Prathyaksha and Anumana
Sankhya and Yoga – Prathyaksham, anumanam, agama
Nyaya – prathyaksham, anumanam, agama, and upamana
Prabhakara Mimamsa – Prathyaksham, Anumanam, Agamam, Upamanam and Arthapathi
Vedanta and Bhatta Mimamsa - Prathyaksham, Anumanam, Agamam, Upamanam, Arthapathi and Anupalabdhi.

(contd.)