Ratnakirtti (950 A.D.) sought to prove the momentariness of all existence (_sattva_), first, by the concomitance discovered by the method of agreement in presence (_anvayavyapti_), and then by the method of difference by proving that the production of effects could not be justified on the assumption of things being permanent and hence accepting the doctrine of momentariness as the only alternative. Existence is defined as the capacity of producing anything (_arthakriyakaritva_). The form of the first type of argument by anvayavyapti may be given thus: "Whatever exists is momentary, by virtue of its existence, as for example the jug; all things about the momentariness of which we are discussing are existents and are therefore momentary." It cannot be said that the jug which has been chosen as an example of an existent is not momentary; for the jug is producing certain effects at the present moment; and it cannot be held that these are all identical in the past and the future or that it is producing no effect at all in the past and future, for the first is impossible, for those which are done now could not be done again in the future; the second is impossible, for if it has any capacity to produce effects it must not cease doing so, as in that case one might as well expect that there should not be any effect even at the present moment. Whatever has the capacity of producing anything at any time must of necessity do it. So if it does produce at one moment and does not produce at another, this contradiction will prove the supposition that the things were different at the different moments. If it is held that the nature of production varies at different moments, then also the thing at those two moments must be different, for a thing could not have in it two contradictory capacities.
Since the jug does not produce at the present moment the work of the past and the future moments, it cannot evidently do so, and hence is not identical with the jug in the past and in the future, for the fact that the jug has the capacity and has not the capacity as well, proves that it is not the same jug at the two moments (_s'aktas'aktasvabhavataya pratik@sa@nam bheda@h_). The capacity of producing effects (_arthakriyas'akti_), which is but the other name of existence, is universally concomitant with momentariness (_k@sa@nikatvavyapta_).
The Nyaya school of philosophy objects to this view and says that the capacity of anything cannot be known until the effect produced is known, and if capacity to produce effects be regarded as existence or being, then the being or existence of the effect cannot be known, until that has produced another effect and that another _ad infinitum_. Since there can be no being that has not capacity of producing effects, and as this capacity can demonstrate itself only in an infinite chain, it will be impossible to know any being or to affirm the capacity of producing effects as the definition of existence. Moreover if all things were momentary there would be no permanent perceiver to observe the change, and there being nothing fixed there could hardly be any means even of taking to any kind of inference. To this Ratnakirtti replies that capacity (_saamarthya_) cannot be denied, for it is demonstrated even in making the denial. The observation of any concomitance in agreement in presence, or agreement in absence, does not require any permanent observer, for under certain conditions of agreement there is the knowledge of the concomitance of agreement in presence, and in other conditions there is the knowledge of the concomitance in absence. This knowledge of concomitance at the succeeding moment holds within itself the experience of the conditions of the preceding moment, and this alone is what we find and not any permanent observer.
The Buddhist definition of being or existence (_sattva_) is indeed capacity, and we arrived at this when it was observed that in all proved cases capacity was all that could be defined of being;--seed was but the capacity of producing shoots, and even if this capacity should require further capacity to produce effects, the fact which has been perceived still remains, viz. that the existence of seeds is nothing but the capacity of producing the shoots and thus there is no vicious infinite [Footnote ref 255]. Though things are momentary, yet we could have concomitance between things only so long as their apparent forms are not different (_atadrupaparav@rttayoreva sadhyasadhanayo@h pratyak@se@na vyaptigraha@nat_). The vyapti or concomitance of any two things (e.g. the fire and the smoke) is based on extreme similarity and not on identity.
Another objection raised against the doctrine of momentariness is this, that a cause (e.g. seed) must wait for a number of other collocations of earth, water, etc., before it can produce the effect (e.g. the shoots) and hence the doctrine must fail. To this Ratnakirtti replies that the seed does not exist before and produce the effect when joined by other collocations, but such is the special effectiveness of a particular seed-moment, that it produces both the collocations or conditions as well as the effect, the shoot. How a special seed-moment became endowed with such special effectiveness is to be sought in other causal moments which preceded it, and on which it was dependent. Ratnakirtti wishes to draw attention to the fact that as one perceptual moment reveals a number of objects, so one causal moment may produce a number of effects. Thus he says that the inference that whatever has being is momentary is valid and free from any fallacy.
It is not important to enlarge upon the second part of Ratnakirtti's arguments in which he tries to show that the production of effects could not be explained if we did not supposeall things to be momentary, for this is more an attempt to refute the doctrines of Nyaya than an elaboration of the Buddhist principles.
The doctrine of momentariness ought to be a direct corollary of the Buddhist metaphysics. But it is curious that though all dharmas were regarded as changing, the fact that they were all strictly momentary (_k@sa@nika_--i.e. existing only for one moment) was not emphasized in early Pali literature. As'vagho@sa in his _S'raddhotpadas'astra_ speaks of all skandhas as k@sa@nika (Suzuki's translation, p. 105). Buddhaghosa also speaks of the meditation of the khandhas as kha@nika in his _Visuddhimagga._ But from the seventh century A.D. till the tenth century this doctrine together with the doctrine of arthakriyakaritva received great attention at the hands of the Sautrantikas and the Vaibha@sikas. All the Nyaya and Vedanta literature of this period is full of refutations and criticisms of these doctrines. The only Buddhist account available of the doctrine of momentariness is from the pen of Ratnakirtti. Some of the general features of his argument in favour of the view have been given above. Elaborate accounts of it may be found in any of the important Nyaya works of this period such as _Nynyamanjari, Tatparyya@tika_ of Vacaspati Mis'ra, etc.
Buddhism did not at any time believe anything to be permanent. With the development of this doctrine they gave great emphasis to this point. Things came to view at one moment and the next moment they were destroyed. Whatever is existent is momentary. It is said that our notion of permanence is derived from the notion of permanence of ourselves, but Buddhism denied the existence of any such permanent selves. What appears as self is but the bundle of ideas, emotions, and active tendencies manifesting at any particular moment. The next moment these dissolve, and new bundles determined by the preceding ones appear and so on. The present thought is thus the only thinker. Apart from the emotions, ideas, and active tendencies, we cannot discover any separate self or soul. It is the combined product of these ideas, emotions, etc., that yield the illusory appearance of self at any moment. The consciousness of self is the resultant product as it were of the combination of ideas, emotions, etc., at any particular moment. As these ideas, emotions, etc., change every moment there is no such thing as a permanent self.
The fact that I remember that I have been existing for a long time past does not prove that a permanent self has been existing for such a long period. When I say this is that book, I perceive the book with my eye at the present moment, but that "this book" is the same as "that book" (i.e. the book arising in memory), cannot be perceived by the senses. It is evident that the "that book" of memory refers to a book seen in the past, whereas "this book" refers to the book which is before my eyes. The feeling of identity which is adduced to prove permanence is thus due to a confusion between an object of memory referring to a past and different object with the object as perceived at the present moment by the senses [Footnote ref 256]. This is true not only of all recognition of identity and permanence of external objects but also of the perception of the identity of self, for the perception of self-identity results from the confusion of certain ideas or emotions arising in memory with similar ideas of the present moment. But since memory points to an object of past perception, and the perception to another object of the present moment, identity cannot be proved by a confusion of the two. Every moment all objects of the world are suffering dissolution and destruction, but yet things appear to persist, and destruction cannot often be noticed. Our hair and nails grow and are cut, but yet we think that we have the same hair and nail that we had before, in place of old hairs new ones similar to them have sprung forth, and they leave the impression as if the old ones were persisting. So it is that though things are destroyed every moment, others similar to these often rise into being and are destroyed the next moment and so on, and these similar things succeeding in a series produce the impression that it is one and the same thing which has been persisting through all the passing moments [Footnote ref 257]. Just as the flame of a candle is changing every moment and yet it seems to us as if we have been perceiving the same flame all the while, so all our bodies, our ideas, emotions, etc., all external objects around us are being destroyed every moment, and new ones are being generated at every succeeding moment, but so long as the objects of the succeeding moments are similar to those of the preceding moments, it appears to us that things have remained the same and no destruction has taken place.