One of the most famous Buddhist tropes is the distinction between “conventional truth” and “ultimate truth”. While these terms never appear in the Nikāyas, and so cannot be traced back to the Buddha himself, they do trace to the abhidhamma period, perhaps as a potential explanation for the copious and problematic use of “self” talk within the Canon.
Although the Buddha taught that all dhammas were “non-self” (anatta), nevertheless he did talk about himself. Although he taught that one could not say whether one existed in the past or the future, nevertheless he did talk about his past actions and future plans.
On the face of it, these appear to be contradictions. Either there is a self or there is not; either the self can be distinguished in the world and discussed as such, or it cannot.
One potential response to this dilemma is, basically, to grab for both horns at once. In Buddhist philosopher Nāgārjuna’s (2nd-3rd c. CE) formulation, there are “two truths”, or two kinds of truth:
The Buddha’s teaching of the Dharma
Is based on two truths:
A truth of worldly convention
And an ultimate truth. (Mūlamadhyamakakārikā 24.8)
There is the level of conventional truth in which exist selves, and there is the level of ultimate truth in which there do not. At the conventional level, one can speak truthfully of having a self. One can truthfully say that “By oneself alone is one purified” (Dhammapada 165). On the other hand, at the ultimate level one can speak truthfully of not finding a self. One can truthfully say that “All things are not-self”. (Dhp. 279).
Here the analogy is often made to cases of illusion or misperception, for example being misled by a mirage on a hot day at noontime. (Saṃyutta Nikāya 22.95). It appears that there is a pool of water ahead, but one who “inspects it, ponders it, and carefully investigates it” would find that in fact there is only sand.
In this sense (although perhaps not for Nāgārjuna) “ultimate truth” expresses something metaphysically prior to “conventional”: it expresses reality, the way things really are. There really is only a flat expanse of sand ahead. “Conventional truth” on the other hand doesn’t express reality accurately. It merely expresses forms of misperception. It expresses our ignorant way of taking things: how we perceive the world when we do not ponder and investigate carefully enough.
Varieties of Conventional and Ultimate Truth
At first glance then the distinction between conventional and ultimate truth seems unproblematic, maybe even banal. Of course there is a difference between talking about the mirage of an oasis and a real oasis. Of course we can misperceive and misunderstand the world.
In the Visuddhimagga, Buddhaghosa (5th c. CE) gives an example which I think helps illuminate the difference between conventional and ultimate truth:
Suppose there were three people, a child without discretion, a villager, and a money-changer, who saw a heap of coins lying on a money-changer’s counter. The child without discretion knows merely that the coins are figured and ornamented, long, square or round; he does not know that they are reckoned as valuable for human use and enjoyment. And the villager knows that they are figured and ornamented, etc., and that they are reckoned as valuable for human use and enjoyment; but he does not know such distinctions as ‘This one is genuine, this is false, this is half-value’. The money-changer knows all those kinds, and he does so by looking at the coin, and by listening to the sound of it when struck, and by smelling its smell, tasting its taste, and weighing it in his hand, and he knows that it was made in a certain village or town or city or on a certain mountain or by a certain master. (XIV, 4)
Knowledge and technical proficiency makes a difference to how accurately we see the world, although in Buddhaghosa’s case the distinction is closer to that between partial and complete than conventional and ultimate.
Of course, the paradigm example of the money-changer’s technical knowhow is that realized through the sciences. We know, for example, that color perception is largely an illusion: although phenomenal colors do roughly track wavelength, this is far from always the case. For examples, Akiyoshi Kitaoka has many such illusions on his webpage.
Further, the fact that humans see the particular phenomenological spectrum we do, whereby any color can be produced by the mixing of three hues of light, is wholly due to our retinas having three different kinds of cone cells, each sensitive to stimulation by a particular wavelength of light. This is called “trichromacy”, so most humans are “trichromats”. So called “colorblind” people are typically those with two kinds of cones, also called “dichromats”; they will only require two light hues to produce all possible colors.
On the other side of the scale, several kinds of animals are “tetrachromats”, and perhaps even “pentachromats”. Their visual fields will be at least as different from ours as ours is from someone who is colorblind, and they will see colors which we literally cannot imagine. This implies that colors per se are not features of the external world, they are only features of our responses to the world. In that sense we might say that color-talk exists on the level of conventional truths about surface reflectance while claims about wavelengths of light would be the ultimate truths.
If we were talking about the phenomenology of vision however, the case would be different. Then colors — or so-called “color qualia” — appear to be the basic features, for which no further analysis is possible: there just is a way this leaf looks green, and that’s an end to the analysis. So phenomenologically, the ultimate truths would involve color-talk.
Lots and Lots of Levels
As we saw in Buddhaghosa’s example, and apparently in contrast to the claims in certain Theravāda commentaries, there appears to be more than one kind of conventional truth. The child sees figured and ornamented metal pieces, while the villager knows their value as media of exchange: these are different ways to view the coins, but neither can be precisely called “false”, at least on a conventional level. They are, one might say, both good so far as they go. One may in some sense be more complete, or closer to the truth, than the other, but both are still true.
In the same fashion, some philosophers of science have said that there are levels of truth in the sciences, or scales of reduction. So, for example, the claims in chemistry may not be ultimately true, but they are more complete and accurate than those in biology, or psychology, or economics. Or one might say that economics, truly understood, reduces to psychology of a certain kind: if we only knew the psychology of each mind involved in economic interactions, we would have a complete science of economics. Then of course psychology in some sense may be cashed out in neurological terms, neurons in chemical terms, and so on down to basic physics.
This all goes well beyond Buddhism, much as some might like to find echoes of contemporary physics in the dhamma. The main issue is that the notion of a singular “conventional truth” cannot really be supported, either in the premodern understanding of the world provided by Buddhaghosa, or in the understanding given us through the sciences. If there are such things as conventional truths, there are a lot of them about any given subject matter.
Does “anything go” then with respect to conventional truths? If it’s to be a useful concept, we need some way to distinguish what counts as a “conventional truth”, as opposed to counting simply as a “falsehood”. Mark Siderits defines a statement as “conventionally true”
… if and only if it is acceptable to common sense and consistently leads to successful practice. (p. 56)
As it stands this is not a very satisfactory definition. At the very least it does not clear up much of our confusion as to how to distinguish true from false conventional claims. Indeed, it doesn’t even distinguish conventional from ultimate very well. For example, it is paradigmatically Buddhist to claim that one cannot practice successfully if one is deluded about the existence of self. Yet belief in a self is the paradigmatic conventional truth.
Now, if this were a philosophy paper we might work to refine Siderits’s definition in order to overcome these problems. For our purposes it is perhaps sufficient to note that there are many ways to “lead to successful practice”, and many beliefs that do so. For some people, to claim that global warming is false “consistently leads to successful practice”: it makes them lots of money. For some people, “it is acceptable to common sense” that ghosts exist, or the Christian God. For others, of course, none of this would qualify as anything other than falsehood, conventional or no.
A lot gets shoved under the rug when we claim that “conventional truth” is simply a point about the existence of a self, which is apparently how it all got started. Conventions come cheap. However the concept “truth” is precious: if split, it shatters.
Is there an Ultimate?
To return to Buddhaghosa’s example, we would not want to say that the money-changer had grasped the “ultimate truth” about any particular coin. (That was not the point of the example, anyhow). From a scientific standpoint, much more can be known and said about a coin than simply “by looking at the coin, and by listening to the sound of it when struck, and by smelling its smell, tasting its taste, and weighing it in his hand”. We could analyze its chemical makeup, for example. Would such an analysis lead us to some kind of “ultimate truth”, though? No, because there is always further analysis to be done.
Eventually such an investigation would lead us to the fundamental constituents of physical matter, and to claims of our most basic physics. But even here we do not have a grasp on “ultimate truth”. Our current physics is incomplete: it is not yet anything like a Theory of Everything. In particular, gravity has not yet been adequately understood in quantum mechanical terms.
Perhaps we would like to think that a future unified physics would supply us with “ultimate truth” in the form of a Theory of Everything, but here we run into our deepest epistemic problem. We can never know that our present theory, however good it is, really is the correct theory. It always remains possible that our knowledge will break down at higher levels of energy, at greater distances, at smaller scales, at distant times, at beyond the farthest bounds of our ability to measure. So if there are in fact sentences which are “ultimately true”, sentences that express the true state of affairs in the single best possible Theory of Everything, we can never know with certitude which ones they are. That’s because we will never know if our theory is actually the best, or if it is another example of Newtonianism: true near our level of energy, mass, velocity, acceleration, but false outside of it.
It may also be that there simply is no single, best Theory of Everything. Perhaps reality is (as they say) like an infinitely layered onion. If it were, there would be no way we could know it, since we cannot perform an infinite number of experiments in a finite time, and a finite time is all we will ever have.
You may well say that this hardly matters: if our understanding allows us to predict everything we require of it with arbitrary accuracy (which it will never do, but set that aside for the present), then it hardly matters if there is some realm of energy in which it breaks down. What we will have will be just as good as knowing the ultimate truths. And perhaps that’s the point: truths only matter insofar as they can be put to use somehow, for example in successful predictions. The problem therefore with the concept “ultimate truth” is that it claims to go beyond mere use.
In the history of Buddhist philosophy, theories of “ultimate truth” ramified greatly, from the realism of the abhidhamma, where the ultimate was constituted by momentary psychophysical events, to the non-dual consciousness of Yogācāra, to the ineffabilism of the Madhyamaka. Seen from the perspective of centuries, the process seems to have been a kind of distancing and dilution of the “ultimate” from something close in and comprehensible (things and phenomena) to something so recondite and esoteric as to be quite literally indescribable. At that point I think we reach a kind of reductio ad absurdum of the concept “ultimate truth”, at least as a matter of Buddhist philosophical history. I doubt Nāgārjuna would entirely disagree.
Conventional and Ultimate Truth in the Nikāyas
It can never be entirely clear what the Buddha would have made of any development that occurred after his passing, but I think we can at least hazard a few educated guesses, based on the extant work.
There is a sense in which the Buddha might have accepted something like a distinction between conventional and ultimate truth: that is, he did equivocate when it came to the self. Sometimes he said (or seemed to say) it was real and important, other times he said quite emphatically that it was not. Further, much of the material of the Nikāyas is about our continual misperception of the world: we see the impermanent as permanent, the non-beautiful as beautiful, the unbeneficial as beneficial, and so on. In our daily lives we often tend to be wrong, sometimes radically so, in our evaluation of the way things are.
The Nikāyas do contain a very few references to manners of speaking about the self, so confusion about this must have been an issue even in the Buddha’s day. For example,
If a bhikkhu is an arahant,
Consummate, with taints destroyed,
One who bears his final body,
He might still say, ‘I speak,’
And he might say, ‘They speak to me.’
Skillful, knowing the world’s parlance,
He uses such terms as mere expressions. (SN 1.25)
[When talking about various kinds of self], these are mere names, expressions, turns of speech, designations in common use in the world, which the Tathāgata uses without misapprehending them. (Dīgha Nikāya 9.53).
No doubt the Buddha would have understood some general notion of “conventional truth”. There is “the world’s parlance”, involving “designations in common use in the world”. Such phrases as these are in common usage, they do not need to be explained or philosophically clarified.
The closest the Buddha ever gets to discussion of “ultimate truth” in the Canon involves the three marks of existence and Right View itself. The three marks of existence are that all compounded things are impermanent, that all compounded things are unsatisfactory, and that all things are non-self. (Dhp. 277-279). These are, one might say, the metaphysical bedrock of the dhamma. In “A World of Impermanence” I argued that of the three, impermanence was the most basic, at least as regards saṃsāric reality: impermanence is the way things are that, in the presence of ignorance, produces the dissatisfaction that makes the Buddhist path necessary. Without impermanence, the path would be idle.
Doctrinally however, the Four Noble Truths constitute what might be termed “ultimate truth”, at least in the Nikāyas: they are the most fundamental truths that constitute and permeate the Buddha’s dhamma.
Nevertheless I do not believe that the concepts “conventional truth” and “ultimate truth” belong in the Buddha’s discourse. I do not believe he would have welcomed them. For the Buddha “truth” was antidote to the ignorance that, in the presence of impermanence, produces dukkha. Impermanence cannot be overcome, but ignorance can.
And what, bhikkhus, is ignorance? Not knowing suffering, not knowing the origin of suffering, not knowing the cessation of suffering, not knowing the way leading to the cessation of suffering. This is called ignorance. (SN 12.2).
There is no sense here of a distinction between “conventional” and “ultimate”. There is just truth, or these few truths, lived, experienced, and directly known. Once we begin to introduce grades or kinds of truth, we have I think moved into more exclusively philosophical territory. It’s a move intended to ‘clean up’ a reasoned exposition of the dhamma, but in a way that only a certain kind of intellectual would love, since as we have seen in fact it introduces more questions than it resolves.
The distinction between “ultimate truth” and “conventional truth” was formulated in the abhidhamma to clean up apparent contradictions in the Buddha’s teaching. This lead to a kind of hypostasization of momentary events as the only features of the world that could be said to exist with “ultimate truth”. While I believe that is the correct realist interpretation of the dhamma, nevertheless I don’t believe that saying so would have been to the Buddha’s liking. For the Buddha, the problem was always and only the extinction of dukkha. Knowing what might be the most basic features of reality has nothing essential to do with such an end; it only engenders useless disputation.
Later Buddhist thinkers like Nāgārjuna, perhaps partly due to skepticism with these disputed views, revisited them in a new light, reinterpreting basic terms like the Sanskrit “svabhāva” in ways that made them untenable. In so doing they no doubt saw themselves as purifying the dharma of a certain kind of pointless scholasticism. Whether or not they were successful in such a project is irrelevant, though they are taken to have been by most Tibetan or Tibetan-trained exegetes. What is relevant however is that the Buddha would likely have been just as uninterested in the philosophical elaborations of the Madhyamaka as he would have been those of the later abhidhamma. For no matter what Nāgārjuna or his followers might say, the Madhyamaka is just as much a “thicket of views” (Majjhima Nikāya 2.8) as is any other developed philosophical system. For evidence of this, one only need note the extraordinary breadth of argument and disagreement it has produced between its proponents, as well as the inarguably abstruse nature of their disputes. The same is true of the doctrine of two truths itself.
Development and elaboration of these doctrines amounts essentially to philosophizing for its own sake. Though those involved did believe they were advancing the dharma by arguing and debating, I think even a glance at the tenor of the later philosophical debates reveals them to be different in kind from the goals and interests of the Buddha as described in the Nikāyas.
Perhaps then the best way to approach the distinction between the two truths is by setting them to one side. In the words of an old professor of mine and sometime antagonist of Buddhism,
The locution ‘ultimate truth’ is redundant and ‘conventional truth’ is an oxymoron. (Yandell/Netland, p. 128).
We need something both simpler and more profound than we find in the doctrine of two truths. In place of two, I would suggest a return to four.
Bhikkhu Bodhi. Various Nikāyas (Wisdom).
Gil Fronsdal (Trans.) The Dhammapada (Shambhala, 2005).
Jay Garfield. The Fundamental Wisdom of the Middle Way (Oxford, 1995).
Bhikkhu Ṇāṇamoli (Trans.) The Path of Purification (Buddhist Publication Society, 1975).
Mark Siderits. Buddhism as Philosophy (Hackett, 2007).
Maurice Walshe. The Long Discourses of the Buddha (Wisdom, 1987).
Keith Yandell and Harold Netland. Buddhism: a Christian Exploration and Appraisal (InterVarsity, 2009).