Of the many philosophical developments from the Buddha's viewpoint, possibly the most in line with the Buddha's traditional silence about philosophical questions was that of the Madhyamika school, as voiced by the philosopher Nagarjuna. It is unlikely that any philosophical exploration of ontological and epistemological issues would have especially reflected the Buddha's original intent, but of the many philosophical detailings that ultimately came out of his tradition, the exploration of Nagarjuna would probably have displeased him the least. This is because Nagarjuna's intent was to answer the questions to which the Buddha only responded with silence, and because Nagarjuna's answer was arguably very close to the same thing--shunyata. Where other Buddhists proposed existent mind or matter, Nagarjuna proposed nothing as independently existing. Everything was dependently originating. Nagarjuna's most important argument was his philosophical dialectic, the result of which, he maintained, was the conventional proof that no philosophical explanation of reality was ultimate. Unfortunately for Nagarjuna, his proof may not have been as complete as he thought--he may be saying more in espousing shunyata than his dialectic is able to prove.
Nagarjuna is taken to be the voice of the Madhyamika school (Koller 196). Unlike other Buddhist thinkers, he did not abandon philosophical enquiry altogether. Instead, he used a philosophical examination to show how common ideas of permanence and causality, upon which our conventional ideas about the universe are based, are inadequate or self-contradictory. Nagarjuna's primary argument was against causality. He argued that the concept of causality ultimately contradicts itself. Nagarjuna asserted that there were only four possible relationships that an effect can have with its cause. Either it is caused by itself alone, by something other than itself, by itself and some other thing, or by neither itself nor another. This is merely a detail of the possibilities for causal connections. Nagarjuna argued: If a thing was caused by itself and nothing else, then no change has occurred and nothing has been caused. If a thing is caused by something other than itself, then something has been produced from nothing. If a thing is caused both by itself and by some other thing, then in the extent to which it is self-similar, there is no change or causation, and in the extent to which it is caused by something else, something has come from nothing, which cannot be. Finally, if a thing is caused by neither itself nor anything else, it has not been caused, because there is no cause. Thus, Nagarjuna argues, nothing can be caused by another thing.
Another important argument that is yielded by Nagarjuna's dialectical method is against ordinary notions of time. He argues that if present and future depend on the past, as we believe, that they would have to exist in the past. But they do not. If they do not exist in the past, they must not be dependant on the past. If they are not dependant on the past, what can they be dependant on? Thus, Nagarjuna concludes, time must have no concrete reality and can only make sense in reference to other dependently originating things. Taken together, these arguments go a long way toward supporting Nagarjuna's idea that conventional ideas about reality are inadequate. They go a long way to suggest that the ultimate nature of reality may be shunyata, or emptiness.
There are a number of traditional responses to Nagarjuna's dialectic. One claims that Nagarjuna's version of reality is nihilistic--because there is no ultimately existent reality. Nagarjuna escapes this criticism by pointing out that his dialectic contains no propositions, it only shows how conventional propositions contradict one another. He also says of shunyata that it is only empty insofar as it is impossible to categorize using conventional notions. Indeed, Nagarjuna splits reality into two truths--conventional truths which we live with and entertain, and ultimate truth, which is not describable in words and can only be called shunyata. Other critics claim that his view is self-critical--that if shunyata cannot be described in conventional terms, then his dialectic and his distinction between conventional and ultimate truth are conventional and so cannot reflect ultimate reality. Nagarjuna counters by claiming that though conventional truth is not ultimately true, it can point to ultimate truth, which his philosophy does.
Nagarjuna's ultimate purpose was similar to the Buddha's--he intended to show that philosophical notions are inadequate to describe ultimate reality, that it must be experienced. Unlike other Buddhists who shunned philosophical approaches, Nagarjuna thought that it would be helpful to come to a philosophical understanding of the problem of philosophy on the way to experiencing ultimate reality directly. But did Nagarjuna succeed in proving that ultimate reality is shunyata? Is there a clear connection between his negative argument and his positive assertions? I submit that there is not. Nagarjuna's negative argument is strong and clear. He proves with great adeptness that conventional notions of time and causality are less than ultimately coherent. He admits that they serve conventional purposes well and sets up a scheme for talking about causal relationships as characterized by conditions rather than causes. But does it follow from the inadequacy of current conventional notions that any conventional notion would be inadequate? This is definitely unclear.
If we consider current notions of time (t1) and causality (c1) as two of a set D of possible descriptions of reality, such that D contains descriptions t1, c1, t2, c2... tn, cn, then what Nagarjuna succeeds in proving using his dialectic is not-t1 and not-c1. Since Nagarjuna's negative argument is strong, we accept not-t1 and not-c1. But Nagarjuna's positive argument, that the ultimate reality cannot be described in conventional terms has a different flavor than merely not-t1 and not-c1. Nagarjuna's positive argument is more of the sort not-D, that no conventional description of reality can reflect ultimate reality accurately, that shunyata is called empty precisely because it is uncategorizable in conventional terms. Nagarjuna is attempting to employ the Law of the Excluded Middle, but the situation is far too complex to admit such a polarized distinction (Murti 146). Nagarjuna seeks to exclude all possible explanations by excluding the ordinary ones, and in this respect his argument fails to be adequate. Granted, he will functionally exclude most or all of the ordinary notions that we entertain, ideas of time and causality being as central as they are to our ways of thinking. But it is important to note that just because we have no concepts of reality which do not fail to include ideas of time or causality, does not mean they cannot exist. Nagarjuna's argument needs either a proof that the set of possible descriptions D can only contain t1 and c1, or a list of all other possible t and c, why they are the only possible t and c, and how they are inadequate.
Nagarjuna's denial of time and causality primarily denies the possibility of change for independently existing objects. Thus it denies the appropriateness of our concepts of time and causality. What it fails to deny (and indeed Nagarjuna would probably espouse) is the idea of a connectedness between objects or events that we ordinarily think of as being causally related. If our intuition of connectedness is correct, then the conventional conceptual framework need not be denied the status of ultimacy on the sole basis of inadequate notions of time and causality. Ultimately, what Nagarjuna succeeds in proving is that our notions of time and causality are inadequate, so if we can correct, replace, or remove these faulty notions from our conventional understanding, it may not be subject to Nagarjuna's criticisms.
For example, we may consider causality as a number of discrete conceptual components working together: time, change, and connectedness. The concept of time involves a reality that exists moment to moment, with an existent present moment a no-longer-existent past moment, and a yet-to-exist future moment. The idea of change involves independent objects which once were, now are, and will be but are not yet. Note that change and time are almost inextricably bound (not as discrete as we would like)--general concepts of past and future involve a change of the present moment, and require a change of present objects to be detectable. Connectedness, on the other hand, is altogether a different sort of concept than either time or change, and requires connections to neither. Thus it may not be fallible to the same arguments. In fact, we avow the continuity of spatial relationships, both within and without objects, as a kind of connectedness not subject to time or change. That is, we ordinarily think of one slice of desk, mountain, or air as being connected to the next by virtue or its proximity, and we are not required to compare one moment to the next or establish a causal relationship for the connection to be plausible. It just is. We just think of space as a continuous continuum. If we take the concept of causality, then, and remove from it the notions of time as coming-to-be and ceasing-to-be, cut out the notion of change entirely, and come to view it in the same way we ordinarily view space, we avoid entirely the notions of time and causality that Nagarjuna proved faulty. Our universe, then, would become a four-dimensional solid in which no change occurs. (Human consciousness should not be a problem for this so long as it is viewed as completely material and as such completely determined).
And this alternative notion of time has important implications for many of negative Buddhist arguments which shore up notions of dependant origination or shunyata. The argument against permanence, for instance, is undermined because the universe would be static. The concept is not perfect, it conflicts with ordinary notions of humans, for instance, but that may only mean that our ordinary notions of humans are inadequate. Despite the obviously unsavory implications and possible problems of such an alternative conception of time and causality (the impossibility of human freedom, for instance), it illustrates an important point--that there are other possible members of the set D (other ways to ground our conceptual framework than traditional notions of time and causality) whose possibility Nagarjuna has failed to deny or whose inadequacy Nagarjuna has failed to show.
Nagarjuna was attempting to answer the philosophical questions--the questions to which the Buddha remained silent. He thought that he could help people to realize the ultimate nature of reality by showing how conventional truths fail to be ultimately true. He attempted to do this by showing, through his dialectic, that since conventional notions are contradictory the nature of the ultimate reality must be uncategorizable--shunyata. Unfortunately, because current conceptions of causality are not the only possible conceptions of causality, Nagarjuna's argument is missing one of two important steps. For his argument to be convincing, he must either prove that the set D of possible conceptions of reality can only include current notions of time and space, or he must list the other possible notions of time and space and show how they are inadequate. Note that the possibility of other conceptions of time or causality is insufficient to disprove Nagarjuna's positive argument. The ultimate nature of reality may well be shunyata, and conventional notions of reality may truly lack the potential to do more than point at reality. Even so, the necessity for a connection between his positive and negative arguments remains. In the end, it seems that philosophical undertakings demand a rigor that the Buddha's silence did not. Perhaps, if enlightenment is possible without tackling philosophy on its home field, then the Buddha's response was the more prudent, if not the more convincing.
Bibliography
Koller, John M. Oriental Philosophies. Englewood Cliffs, New Jersey: Prentice Hall.1985.
Murti. T. R. V. The Central Philosophy of Buddhism: A Study of the Madhyamika System. London: Ruskin House. 1960.
Jha, Ram Chandra. The Vedantic and the Buddhist Concept of Reality as Interpreted by Samkara and Nagarjuna. Calcutta: Print O Print. 1973.