We have considered the Nyaya doctrine of pramana or the methods of knowledge. Now we come to the second topic of Prameya or the objects of knowledge according to Gautama, ‘as already seen”, these are: the self, the body.
The senses and their objects, knowledge, mind (manas), pravrtti or activity, dosa or the mental imperfections, pretyabhava or rebirth, phala or the feelings of pleasure and pain, duhkha or suffering, apavarga or absolute freedom from all sufferings.
There are also such objects as dravya or substance, guna or quality, karma or motion, samanya or the universal, visesa or particularity, samavaya or the relation of inherence, and abhava or non-existence.
All of these prameyas or knowables are not to be found in the physical world, because it includes only those objects that are either physical (bhuta) or somehow belong to the world of physical nature.
Thus the self, its attribute of knowledge and manas are not at all physical. Time and space are two substances which although different from the physical substances, yet somehow belong to the physical world.
Akasa is a physical substance which is not a productive cause of anything. The physical world is constituted by the four physical substances of earth, water, fire and air.
The ultimate constituents of these four substances are the eternal and unchanging atoms of earth, water, fire and air. Akasa or ether, kala or time, and dik or space is eternal and infinite substances, each being one single whole.
Thus the physical world is the product of the four kinds of atoms of earth, water, fire and air. It contains all the composite products of these atoms, and their qualities and relations, including organic bodies, the senses, and the sensible qualities of things.
To it belongs also the physical substance of akasa or ether. The non- physical, infinite substances of kala or time and dik or space contain and interrelate all physical things and events in various ways.
The Nyaya theory of the physical world, in respect of these and other connected subjects, is the same as that of the Vaisesiko.
The Vaisesika theory, which is a more detailed account of the subject, is accepted by the Nyaya as samanatantra or an allied theory common to the Nyaya and the Vaisesika systems. So we propose to take up this subject when we come to the Vaisesika philosophy.