While discussing the universal causal efficiency (vastutva), it was stated that a substance is characterized by persistence/permanence-through-change. While the quality 'causal efficiency' emphasizes the aspect of change, this quality viz. agurulaghutva emphasizes the aspect of persistence/permanence.
It is precisely this quality, which prevents the substance from surrendering its own specific substancehood, and prevents the quality from abandoning its 'qualityhood'. Further, both the substance and the quality undergo infinite modifications, intrinsically as well as extrinsically. But they do not lose their identity.
Secondly, the interaction between two substances can never change the specific nature of either substance.
Thirdly, each substance, which is the substratum of infinite qualities of its own, continues to support its substance and they do not scatter away. The inalienability of the respective qualities of each substance also is due to this quality of agurulaghutva.
All these mean that each substance and its characteristic qualities maintain their individuality in-spite of not only the interaction between two or more substances but 'self-interaction' also. The phenomena of ceaseless self-interaction have its parallel in the 'self-interaction of nucleons' very recently discovered in the subatomic reactions. According to Jains, such self-interaction is not restricted to physical existence (pudgala) only, but also extends to all the substances. It is called "sadguna-hani-vrddhi", i.e. "six-steps of infinitesimal changes in descending as well as ascending order". We shall revert to this important phenomenon in the next chapter.
After this brief description of six real existents, we shall take up detailed discussion on pudgala i.e. physical existence.
The quality agurulaghutva is thus responsible for maintaining the individuality of the substance and its characteristic properties. The intrinsic modifications of the substance are in the form of "self-interaction" and takes place in 12 steps: 6 upward and 6 downward.
An infinitesimal change takes place in each step and can be mathematically and expressed as under.
The six steps upwards are:
- infinitesimal increase
- by a countless fraction
- by a countable fraction
- numerable times
- innumerable times
- infinite times
The six steps downwards are in exactly reverse order.