(2) Inference (anuman) and
(3) The statement of some authority or Vedas.
1. The Pratyaksha Vidhi:
In this Vidhi or method, the learner obtains the knowledge of a certain object or activity through his own senses. According to Sankhya the knowledge thus obtained reaches even the soul (Atma) through mind, self- consciousness (Ahamkar) and intellect (Buddhi).
Knowledge may be knowledge and usable in life only when there is a perfect co-ordination between senses, mind (Manas), self- consciousness (Ahamkar), intellect (Buddhi) and soul (Atma). For acquisition of knowledge the co-operation between the matter (Jad) and spirit (Chetan) or Purush) is necessary.
Thus according to Sankhya philosophy in the Pratyaksha Vidhi both the external and internal means of knowledge co-operate. Only then the knowledge becomes stable or permanent. Needless to remark that the Pratyakshi Vidhi is the first requisite for learning anything
2. The Anuman Vidhi:
The term Anuman (or inference) means the knowledge based on some previous knowledge (or experience). Thus in the Anuman Vidhi we try to infer about some unknown subject on the basis of some known subject. According to Sankhya there are two types of Anuman—(1) Veet and (2) Aveet.
The Anuman which is based on eternal method is known as Veet and that which is based on eternal negation (Shashwat Nishedh) is called.
According to Sankhya Anuman (inference) is made on the basis of some concrete proof or testimony (Praman), then alone it is beneficial, and when a concrete proof is lacking it may be harmful.
Sankhya philosophy has hit here at a truism. The meaning of language is obtained through some inference. The inductive and deductive or analytic and synthetic method of teaching is only experimentation on the Anuman Vidhi (Inference method). A researcher proceeds on his investigation on the basis of Anuman (inference).
3. Shabda Vidhi:
As we have already said above, the meaning of Shabda is the statement (Vachan) or a trustworthy person (e.g. the Vedavani statements in the Vedas a trustworthy person are he who has the real knowledge of basic elements and of soul (spirit).
Thus the Shabda Vidhi is that method in which we repose confidence in the statements of distinguished persons and acquire knowledge through the great books written by them.
According to Sankhya philosophy at places where it is not possible to acquire knowledge on the basis of Pratyaksha, the perceivable and Anuman (inference), the testimony of Shabda (Apta-Vachan the statements of authorities) should be relied on. But the learner should always weigh the knowledge thus acquired on the balance of his perceivable knowledge (Pratyaksha Gyan).
The Shabda Vidhi is a very universal method of acquiring knowledge. Even today we employ this method for learning many things. The oral, question-answer description and interpretation or exposition method of modern teaching may be easily grouped under the Shabda Vidhi.
The text-book material also is a form of Shabda Vidhi. Supervised-study-method is a very clear example of Shabda Vidhi. Press, Radio, Cinema and television are only other examples of Shabda Vidhi learning in the modern age.