The Three Tests
by Swami Sivananda
n order to understand an object thoroughly in this world, there are three tests or means viz., by approximation, by its characteristics, and by an enquiry into its characteristics. by the first means we know only the name of the object sought to be known; by the second we understand its real nature; and by the third we enquire into such characteristics. According to the second test, the characteristics of an object should not be subject to the faults of Avyapti (non-inclusion or exclusion of part of a thing defined,) Adhivyapti (redundancy) and Asambhava (impossibility) and should thus not be found in another.
Avyapti arises when the characteristics are found in one part of a class only and not in the rest. For example, the cow is of a tawny colour. Here the object cow is subject to the fault of Avyapti, as the tawny colour is an attribute of one class of cows only and not of the whole class. Hence, cow cannot be properly known through this description of it alone.
Adhivyapti arises when the characteristics pointed out are found in (or are common to) other objects also. For instance, the cows are four-legged. Here not only cows but also other animals have four legs. Hence redundancy.
Asambhava is where the characteristics given out are not at all found in the object stated. For instance, the cow is one-hoofed. All cows have two hoofs and not one. Hence impossibility.
That which is not subject to these stains has not the properties that are found in or common to another. For instance, a cow has the characteristics of neck, dewlap, back and hump. Here these characteristics are found in the bovine genus only.