Jain Theory of Knowledge and Cognitive Science: 2.4 Nature of Senses Explained in Biology and Jainism

Neuro Scientists^[11] accepts division of the senses into two groups:

1. External sense and
2. Internal sense.^[12]
   
   

1. External sense

External senses receive the information about outside environment. These include hearing, sight, smell, taste and touch. Each of these is of two types:

1. Distance receiving senses: Detect things that occur far from body i.e. the distant outside in environment with our senses of sight, hearing.
2. Contact senses: Sense of smell, taste, and touch involve contact with body and are called contact external senses.^[13]

If asked which of the five senses, contractile and which are non-contractile, then the answer from Jain point of view is that - out of the five senses, the sense of sight is non-contractile (aprāpyakārī) and the rest of the four are contractile (prāpyakārī). The senses that perceive cognition by the contact of the atomic clusters of sound etc. are known as contractile and the senses that perceive knowledge from a distance and no contact is needed are known as non-contractile. The sense of seeing obtains cognition of the object from a distance, without touching the object; it is therefore, non-contractile. The rest of the four senses obtain the knowledge of sound, smell, taste and touch by coming in contact with their matters. They are therefore contractile.^[14]

In addition the Vṛtti of Acharya Haribhadra on Nandí has further explained contestability in terms of intensity. It classifies sense organs into three types^[15]:

1. Sense organ that apprehends the object on account of the contact with its object as in the case of gustatory sense.
2. Sense organ that apprehends the object on account of its contact and being assimilated with its object as water assimilated in the body, For example, sense of touch, taste and smell.
3. Sense organ that apprehends the object without any contact its object as in the case of visual sense. Here, the word contact refers to tactile contact.

2. Internal sense

Internal senses receives the information about inner environment.

Other Kinds of Classification

Senses are of two kinds has been explained in Jain canons. They are as follows:

1. Dravyendriya (Physical sense)
2. Bhāvendriya (Psychical sense).^[16]

Physical Sense

The internal and the external structure of the organs eyes, ears etc. are known as physical senses. The physical senses being material are non-living. They are of two kinds^[17]:

1. Organic structure (nivṛitti)
2. Material efficiency of the senses (uvagaraṇaṁ)^[18]

The structure of the sense is known as organic structure. Structures are of two types: external and internal. Different creatures have different external structures. Their structures are not of the same type. Internal structures of all the creatures are of the same type as explained by Maladhāri in his commentary of Nandi "the term 'nivṛitti'' means morphology of senses, their shape, structure and size. It is of two kinds- external and internal. For example: