Meaning and Truth

Nagarjuna Conqueror of the Serpent, 1925. A painting by Nicholas Roerich, (1874-1947)

Recently, a friend at work told me that he had listened to a podcast by Sam Harris interviewing Robert Wright concerning Wright's new book Why Buddhism is True. Knowing that I was a Buddhist, he wanted my opinion about it. I told him that Buddhism, particularly Mahayana Buddhism, has a particular philosophical approach to truth that differs considerably from Western philosophy, but that we should rather talk about it some time over a beer (nonalchoholic in my case). I was of course referring to the Mahayana and Vajrayana notion of the Two Truths, which I've written about before in this blog. Though I haven't read the book, I suspect it is not a particularly nuanced discussion of the topic, and that Wright entitled it that (or his publisher did) as a provocation, which, in many cases, helps sell more books. I'm sure the Dali Lama would never so entitle a book, or even make it the title of a talk. But the topic of truth and in particular its relation to the opposite, namely falsehood, or, when uttered by a person, lies, is in the air right now: "fake news", "alternate facts", etc. With respect to the Western society's discussion, the two truths don't have to do with facts and "alternate facts", they have to do with how reality appears to us and how is actually is.


The Two Truths doctrine is shared by all the Mahayana schools, though they differ on certain points, in some cases greatly in other less. Nagarjuna, the 2nd-3rd century monk whose philosophy serves as the basis for the Madhyamaka school of Mahayana (and who I have also written about previously in this blog here and here) held that conventional truth, or how reality appears to us, is about cause and effect, and ultimate truth, or about how reality is, is about emptiness, i.e. that reality, including cause and effect, holds no abiding substance from its own side. Some schools whose line of argument does not descend from the Madhyamaka, for example the Yogachara/Cittamatras, hold that there is no external reality at all, not even conventionally, and everything we experience as conventional reality is simply a construct of our minds. Nagarjuna never goes that far, but he doesn't specify any view with respect to ultimate reality, he simply uses negation to refute any view you, or in the case of his best known work Mulamadhyamikakarika (the Karikas for short) a theatrically postulated opponent, happen to raise. To do otherwise would simply raise his opinion to the status of a "view" which one could then subject to negation to refute.

Most of the argument in Mahayana and Vajrayana philosophy is about ultimate truth, but Wright and the discussion that is up right now in Western society, particularly the US, isn't about ultimate truth, at least not directly. It's about relative truth. Specifically, what constitutes relative truth. And there Nagarjuna and the Madhyamaka, regardless of their particular take on ultimate reality, have a clear message: truth is what corresponds to cause and effect. In the context of the generation of human suffering, that's Dependent Arising, or Pratītyasamutpāda in Sanskirt. In the context of everyday life or science, its about a particular collection of causes (some of which are technically known as "conditions" if they are not perceived to be the main cause) leading to an effect [1]. Even if cause and effect and Dependent Arising are not ultimate truth, as Nagarjuna so skillfully argues in the Karikas, they are how we perceive reality. If a postulated collection of causes does not lead to a specified effect, then the statement that there is a causal relationship is not true. 
  
I made the connection with meaning after recently finishing Asanga's (channeling Maitreya's) work Middle Beyond Extremes (Madhyantavibhaga in Sanskirt). I've been struggling with this work for some time now, but after taking a break, I finally managed to put some of it together. What particularly caught my eye is this:
 

Connection and familiarity,
Lack of connection and no familiarity:
Due to the first two, meaning is present and to the latter two, it is not-
This is being unmistaken about syllables [V.14][2]

What this text is saying is that meaning derives simply from two things: familiarity with the words that were spoken or written and a connection with what the words are designating. The commentaries (in particular, the one written by Ju Mipham, the great 19th century proponent of the Shentong) explain this in more detail. If you are not familiar with the words, for example they are in a language you do not speak or you have never encountered them before, then you won't be able to understand what the other person is saying. Similarly, if you are not familiar with what the words designate, you will not understand. The words will convey no meaning to you. So meaning is really the effect of these two causes, namely familiarity and connection, and their role in human conceptual thought.

The connection between truth and meaning is the following. Meaning is something that is linguistically constructed and is part of the conceptual mind. (Relative) Truth is about cause and effect, a statement about the world. To the extent to which statements about cause and effect are always filtered through the conceptual mind, a disconnect can happen between the truth of how we perceive the world and how we describe it to ourselves (which in many cases can influence how we perceive the world). One person can maintain that the connection sits with a particular designation while the other can maintain that it happens through another designation. Either person can have other reasons for maintaining their view on the designation.

And here's the connection with ultimate truth: because there is no abiding essence to reality, in other words because of emptiness, two people can differ on how they perceive it, on how they perceive the cause and effect. They might even perceive the cause and effect quite differently. The decision to agree about a particular case will therefore cause people to perceive reality differently. That perception can either correspond to the underlying physical realty or it can deny it. To the extent that it denies, the people involved are in for trouble down the road.

Image source: Found in the collection of the International Centre of the Roerichs, Moscow. Photo by Fine Art Images / Heritage Images / Getty Images

[1] I would add here "probabilistically lead to an effect". The ultimate truth of emptiness means that even low probability events, like the sun suddenly disappearing, are still possible. They just don't happen very often if at all. Less extreme cases of multiple possible causes leading probabilistically to an effect are also easy to find. Most classical Buddhist philosophy doesn't deal with probability at all.

[2] Dharmachakra Translation Committee translation, p. 136, Wisdom Books, 2006. 

Meditation and Depression

Graph showing positive effect of Transcendental Meditation (not Mindfulness Meditation) on relief of depression

I hang out a lot on the Dharma Overground discussion list, usually checking it once a day as part of my nightly tour of Web sites I’m interested in. Now and then, someone posts a note that goes something like this:

Hi, I’m new on this site, just found out about meditation. I’ve had depression for a number of years and want to see whether meditation can help to relieve it. Does anybody know…

Often the initial post will sit there unanswered for a while, but sometimes a regular will come on and post something like this:

Welcome to the site. I had the same problem as you for many years. It went away after I started meditating regularly, and so far, it hasn’t come back…

Recently, I posted a response to an initial query that went something like this:

Welcome to the site. My advice is to work with a therapist and if the therapist suggests medication, give it a try. If the initial medication doesn’t work, then there are others. If no medication works, then maybe your genetics is such that drugs won’t help and talk therapy, maybe with some meditation under the guidance of teacher might work.

A couple other people responded as in the previous paragraph. You can read the thread here.

Now, my reason for giving this advice has to do with my experience regarding meditation and depression. Even though I have never had a diagnosis of depression, I experienced major depression after a meditation retreat that I had to leave early in 1996 (you can read about it in my memoir) in which my entire plan for the rest of my life collapsed over the period of about a month. This is what many in the Dharma Overground community and elsewhere call “The Dark Night”. The experience I had is not particularly uncommon but also it is not a forgone conclusion that everybody goes through it. For someone who already has depression, however, starting a serious meditation practice that then leads to further, perhaps deeper depression could be devastating.

So, being a fan of fact based analysis, I got to thinking: what does the research literature say about meditation and depression? Anybody who knows how psychological research works knows that anecdotal reports, such as that cited above by the list posters, are excellent for pointing toward a possible cause-effect relationship, but to really prove it, you need a rigorous statistical study. So I turned to Google Scholar and googled “mediation depression”.

I came across this article on the Web site of the Journal of the American Medical Association. The article is a meta-analysis, which means that it sorts through the primary literature looking at various studies that meet criteria and summarizes the results from those studies. The analysis runs only up until 2012, about when the current popular interest in mindfulness was just starting. The studies surveyed were restricted to those that were randomized clinical trials with controls for placebo effects. Randomized trials are more or less the gold standard when trying to measure cause and effect, and placebo controls are necessary to ensure that the effect is in fact coming from the presumptive cause, and not simply a result of the subject being convinced that they are getting an active treatment, when in fact they are part of the control group. The authors reviewed 47 studies having a total of 3,515 participants.

The results showed that mindfulness meditation had a moderate effect in reducing anxiety, depression, and pain for up to 6 months, but low effect at reducing stress and improving mental health related quality of life. The authors found no evidence that meditation helped with improving mood and attention, reducing or eliminating substance abuse, promoting healthy eating habits, helping with weight control, or improving sleep. In addition, even for depression and anxiety, meditation was no better than other active treatment regimens such as drugs, behavioral (usually cognitive behavioral) therapy, or exercise such as yoga. The authors then go on to note that many of the studies reporting positive effects are uncontrolled or don’t control for placebo effects, and the people conducting the studies often are themselves meditators or have had positive experience with meditation or may have some other vested interest or belief in the effectiveness of meditation for relieving psychological problems.

What to make of this? One way to look at it is that, even though the pharmacological companies have heavily marketed antidepressants for years, they are really not any more effective than meditation, yoga, or talk therapy for helping relieve depression. There is some evidence that genetics may influence the effectiveness of selective serotonin inhibitors (SSIs, the component of many antidepressants). Other studies haven’t found any relationship between a person’s genetics and SSI effectiveness. The same might be true of meditation, that is people with particular genes might benefit more from meditation and talk therapy than from SSIs.* A recent study connected relief from depression to use of probiotics. The digestive tract is known to have many serotonin receptors and the microbiome is currently an active area of research that is turning out to have surprising effects on physical and psychological health. This study has yet to be replicated.

Anyway, based on what I know now, I think I would change my advice to someone who was looking for relief of major depression. The most important point is that you need to work with a therapist, and, if you try meditation, with a qualified (in other words trained) teacher. The reason is that you need to have someone who has the training to give you an objective opinion about whether a particular treatment is affecting your emotional state. Since meditation generally costs little and seems to be about as effective as drugs, starting with meditation is a good way to go. Also exercise, like yoga, and maybe probiotics all are relatively inexpensive and have been shown to help. If you are working with a therapist, then you will probably also be doing some behavioral therapy, and I’ve known some meditation teachers who include that in their approach. Your support network can give you objective feedback. And finally, if nothing else works, try drugs. They are expensive and don't work any better than much cheaper methods.

*I speculated to that effect in the DhO thread, having seemed to recall an article I had recently seen, but upon further searching I could not find the article. 

Image source: https://medicalxpress.com/news/2010-04-depression-transcendental-meditation.html

Karma and Logic

Tibetan Wheel of Life

Nagarajuna has an interesting view on karma. His view is that it is not subject to analysis. This means that you can't approach it logically. The Tibetans classify karma (including rebirth) as the only one of the Buddha's teachings which is Extremely Hidden, which means that it is impossible to find evidence for it. Teachings which are classified as Hidden, like dependent arising, are subject to analysis and evidence can be found, but it requires careful attention. The evidence for other teachings, like on metta, is clearly visible for all to see.

What does this mean? Well, it means that describing a mechanism for karma and rebirth is impossible. By "mechanism", I mean a cause and effect sequence that explains how they work. The mechanism for rebirth comes down to: it's driven by your karma. And the mechanism for karma comes down to: unknown. Incidentally, that karma is the "cause" of rebirth need not be the case. It is possible that someone might be reborn with no connection to the meritorious or unmeritorious acts in their life; in fact, the Buddha explicitly refuted this in one of the suttas.

Why is this a problem? It's particularly a problem for rebirth because from what we know about how humans and other animals come into existence, on the physical side and increasingly on the psychological side, there is always a sequence of causal events and their effects, that determine the outcome, namely the coming into existence of a new being. This sequence of causal events doesn't have a place in it for "this dying person here is reborn as that being there" without any intervening events on the physical and psychological side. For this reason, most Secular Buddhists reject belief in karma and rebirth. Note the use of "events" here, I'm abiding by the modern view of causality, that a cause and effect sequence is primarily the arising of one or several causal events that come together to fashion the effect. This is different from the ancient Indian view, in which a cause was viewed as an object, and the effect was too.

Now, I would argue there is some evidence for karma and rebirth, but it's reliability is somewhat suspect.* As I described in the book, I've had visions of past lives of myself and others during meditation, other contemporary practitioners have as well, and from the sutta reports, the Buddha did too. I think the Buddha probably took these visions at face value, since they reinforced the cultural view that karma and rebirth exist. In addition, it gave him the opportunity to comfort family members who came to him in absolute grief due to the passing of a loved one**. My theory is that he would go off to meditate, go into a deep jhana state, and when he came out, a vision would arise of the next life of the family's departed member. Then he would go back and tell them, to their great relief. Unless of course the vision was of an unfortunate rebirth, in which case the Buddha could use that as a lesson for why ethical behavior is important, hopefully prompting any family members who had the same tendencies to clean up their act.

So karma and rebirth are basically a matter of belief. Though I don't have any proof, I also think whether or not you have visions of past and future lives depends on whether or not you believe in rebirth, as I talk about in the Epilog to the book. What does that say about the actual existence of karma and rebirth? Who knows! Like I said at the beginning, it's impossible to gather any evidence, either physical or psychological, for it. You either believe in it or you don't.

But if you don't, it's not like the Christian view of belief, that you are going to hell if you don't believe in God. It's more like if you don't believe in the science behind global warming and continue to pollute, the planet is going to cook regardless of your belief. In other words, the view is that karma works whether you believe in it or not, and that your next life will depend on how you comport yourself in this life. If you do good acts, then you'll be reborn in a happy destination, if not, well then too late. People in the Secular Buddhist community, like Stephen Batchelor, are perfectly in harmony with the Buddha's teachings if they don't believe in rebirth.

Despite what some Buddhist Web sites and teachers say, you can be a perfectly good Buddhist and not believe in karma and rebirth. The important point is not to behave like a self-centered jerk, and try to bring some generosity and compassion to your interactions with others and yourself. Whether or not you get reborn into a better next life..well, I guess you'll just have to wait and see, eh?



* Another body of evidence comes from Ian Stephanson a former professor at the University of Virginia School of Medicine, who  conducted research by interviewing young children about their memories of past lives. I feel this is in the same category as meditative visions, namely there is no plausible hypothesis about how the memories could have gotten from the former life to the current one, so their cause must be something different.

** This is contrary to the predominant Secular Buddhist view, that the stories in the suttas about the Buddha's visions on past and future lives were added by later editors, to reinforce a particular theological view of the universe.

Image source: buddhaweekly.com

Nirvana: A Fifth View

Mt. Kangchanjunga, Nepal

In a blogpost of April, 2015 titled Meditative Attainments: Four Views of Nirvana, I described four views of Nirvana from different traditions. After spending the last half year studying Nagrajuna's Mulamadhyamakakarika, I think I now understand a fifth view, or maybe lack of view is a better way to put it. Because that is what Nagarjuna's view of nirvana is, the lack of any fixed view at all.

It's difficult to see how this could be possible. Language forces our thinking into classifying the world into objects and what they do, nouns and verbs, with prepositions acting as a kind of relational glue. This observation provides the first hint about one property of this non-view: it is difficult to describe in language. And, to the extent we use language to communicate, the non-view of no fixed view is difficult to communicate at all. The commentators to the Karikas nevertheless felt that the Buddha and other enlightened beings have to communicate with students about what liberation is like, and so they have to use some kind of language.

From the Theravada/Early Buddhist perspective, the Buddha's teaching is all about abandoning desire and aversion through the realization that the self is just a constructed entity and not something fixed. This realization does not come easy. The deep altered states of consciousness coming from the path and fruit (magga and phala) moments in the four stages of enlightenment are needed to sever the bonds between sense perception and the constructed entity of the self. Wynne in his excellent essay "Early Buddhist Teaching as Proto-sunyavada" describes this as "no-self".

Nagarjuna's view which is based on some threads in the Nikayas from the Buddha's teaching, is that, actually, the whole world is a cognitive construction, just like the feeling of self. This isn't to suppose that Nagarjuna was a solipsist or a subjective idealist, in other words, that he believed there is no reality outside of his mind. Rather, his position is that there is an objective reality, but we can never know it as more than an approximation. That's because we construct a view of objective reality from our sense data and the cognitive context we bring to that data. The sense data is constrained by the kinds of events our sense organs can experience. For example, some bees can see into the ultraviolet but humans can't, so bees have a different view of the world than we do. The cognitive context contains such properties as our gender, our native language and any other languages in which we are fluent, our culture, the time and place in which our lives play out, and so forth.


These properties and our limited sense data cause us to interpret the world in particular ways that, if they were to occur to someone else, say a women from the 25th century with genetic enhancements that allow her to see into the ultraviolet who was raised on Mars or a monk from 200 BC India who achieved liberation on the banks of the Niranjara River (aka the Buddha), would result in a different interpretation. Complete liberation from the process by which we construct reality from sense data and our cognitive context seems unlikely to be possible on a permanent basis, though I believe it is possible to experience the constructed nature of reality just like it is possible to experience the constructed nature of the self, through meditation. Being able to realize the constructed nature of our views on reality and treating them lightly, as a hypothesis, rather than as a fixed, immovable, universal, and unending truth is what I believe is Nagarjuna's Fifth View of Nirvana.




Image source:wikipedia.com

Book Review of A Guided Tour of Hell by Sam Bercholz

Picture of the Cosmology of Hell from the Book Jacket

Hell is a topic that most Westerners would rather avoid. Indeed, Sam Bercholz said at his talk I attended on Saturday that when he read Paltrul Rinpoche's Words of My Perfect Teacher, he paged through the descriptions of hell, thinking them to be for Tibetan peasants, and he ignored Dante's Inferno for the Paradiso. But after suffering a massive heart attack at the Palm Springs airport and having a sextuple bypass, Bercholz was in the intensive care ward slowly recovering when he flatlined and literally died. While the medical personnel were frantically trying to revive him, he had a near death experience, but it was not the peaceful, "Tunnel of Light" experience widely reported in the New Age literature. It was an experience of hell. 

This book is a collaboration between Bercholz and an extraordinarily talented Tibetan painter from Los Angeles, Pema Namdol Thaye. The book is lavishly illustrated with Thaye's pictures, and Bercholz subtitles the book "A Graphic Memoir", making the comparison with graphic novels and comics. The pictures of hell are in color, while other pictures depicting Bercholz' life, including a previous near death experience in which he experienced the "Tunnel of Light", are in black in white. Hell in Thaye's depiction bifurcates into two, the hot hells - a roiling place of lava, sulfur and smoke where beings are packed so tightly that some beings are parts of others - and the cold hells were everything is frozen, including the beings who ended up there. Bercholz said that the hot hells are where beings end up whose minds tend toward anger and hatred, while the cold hells are those where beings end up whose minds tend toward disdain.

Bercholz and Thaye spent many hours talking about Bercholz's experience but the power of the pictures comes from Thaye's experience of having visited hell too. As a young child in Tibet, Thaye always wanted to paint pictures of hell, and he is one of a small group of "hell travelers", along with Bercholz: those who have visited hell and returned to speak about it. Bercholz says that the only reason he was able to survive the experience was that he was accompanied on his visit by the Buddha of Hell, a compassionate presence who literally held Bercholz in his hands, and Jhana Sophia, the embodiment of wisdom. Bercholz says that even in hell it is possible to become enlightened and escape. The hell dwellers just need to realize compassion for themselves and those suffering around them, and they will see Jhana Sophia and the Buddha of Hell, and be reborn in another, less suffering intensive realm. But the hell dwellers are so caught up in their own anger and distain that they don't see these two beings.

Most of the pictures show hell as a modern cityscape, not the traditional Tibetan architecture nor even the Renaissance landscape of Dante in his Inferno. Bercholz says that before he entered hell, he encountered Yama, the Lord of Death and the embodiment of impermanence, and that Yama was the only aspect of the entire experience that looked like the traditional Tibetan depiction. A long time student of Tibetan Buddhism whose teachers include Choam Trugpa Rinpoche, Bercholz says that after he was revived, he was surprised that hell looked a bit like a big city having expected that it would look like Tibet, but that after some research in the experience of hell in other cultures, people universally experience it in ways that are consistent with their experience in their life.

Bercholz says that this is due to our "habit of space and time". Being dead, you no longer have a body to ground your experience in the material world so the continuity of your mind begins to construct experiences based on your habits during your life. If that includes habitual anger, hatred, and distain, then you will experience hell. Even though the book is structured as a series of vignettes telling the stories of the suffering beings he met in hell, Bercholz is clear that the actual experience was completely nonconceptual. The stories are an attempt to render this deep, nonconceptual experience into the "and then this happened, and then I met this being and she told me her story..." by which humans pass on their experience to each other. 

I've personally always been interested in hell, read Dante's Inferno with interest when I was in college, and have been a fan of Hieronymus Bosch's art. The description of the Buddhist hells have also drawn my attention, particularly the "Hell of the Iron Doors", where the suffering being is in a room of hot iron and there are doors open on the four walls, but as they run to escape the room, the door slams shut. What exactly hell is or isn't is another question, but from Bercholz' and others description, something seems to be there. Unfortunately, while his and Thaye's book is a fascinating read, the way such an experience is communicated, through stories, is unlikely to reach the people who really need to hear it, those whose lives are ruled by habitual anger, hatred, and disdain. If they could for one minute experience the intensity of the suffering that they are causing others through an experience of hell (100% suffering, 100% of the time), they would likely reconsider their behavior.

So if you are interested in hell or just want to check out some fabulous contemporary Tibetan art, I'd recommend buying the book.
 
Image source: forwardreviews.com

Was Nagarjuna a Well Poisoner?

In today’s New York Times, Alexander George writes in the periodic philosophy column, The Stone, about well poisoners. The essay was specifically directed at the current occupant of the White House, and questioned whether his continued denigration of scientific facts as “lies” and his accusations that the mainstream media promotes “fake news” will end up poisoning the public discourse so that people finally are unable to discuss serious issues based on facts. He cites the case of the Dutch art forger van Meegeren who successfully forged paintings by Vermeer. Van Meegeren was able to do so by managing to convince a prominent Vermeer collector, whose collection was used as the yardstick against which to compare questionable works, that a forgery was an authentic Vermeer. While today it’s completely obvious that van Meegeren’s work looks nothing like Vermeer’s, that move allowed him to pass off his forgeries as authentic. 

George states that this move in philosophy is called “poisoning the well”, and that behind every philosophical skeptic is a well poisoner. He cites the case of Descartes, who, in his work Meditations on First Philosophy completely deconstructs your everyday experience to show that none of your beliefs about the everyday world can be trusted. Descartes does this by raising arguments about the trustworthiness of your senses, and raises the possibility that you are dreaming. According to George, Descartes pulls himself out of his tailspin to his satisfaction, but not to many philosophers’. This kind of move is called “well poisoning” because, like an enemy army trying to cut off the water supply to a village, it is more efficient to poison the well (convince you that you cannot trust what you experience) than to turn off the water at the individual houses (argue each case individually).

Though I’ve never read Meditations on First Philosophy, George’s descriptions of how Descartes argued sounded an awful lot like Nagarjuna’s arguments in the Karikas. So the question arose for me: was Nagarjuna a well poisoner, like Descartes?

Overall, I think not, but with respect to metaphysics, most certainly. What Nagarjuna does is poison the well for those who try to argue philosophically about ultimate reality and metaphysics. He firmly establishes that reality is empty of any ultimate and self-existing objects, and only consists of ephemeral cause and effect events, which he says are “like a dream”. Not that they are a dream, he just uses dreaming as a metaphor. Nagarjuna’s tactics are rather the opposite of a well poisoner, to argue each individual case. Precisely because he wants to completely deconstruct the notion of an ultimate reality with self-existing objects, he cannot base his arguments on any assumed, overarching philosophical framework or view. Even emptiness isn’t such a framework, Nagarjuna says that people who believe emptiness is a view are “incurable”. So we can only talk about reality from a conventional, cause and effect standpoint, not from an ultimate standpoint. Curiously enough, that’s the conclusion I came to (before I even knew a whole lot about Nagarjuna’s thinking) in my practice memoir, Silicon Valley Monk. That’s why I subtitled it: From Metaphysics to Reality on the Buddhist Path.

Image source: http://awoiaf.westeros.org/index.php/Poison

Conventional Reality and Ultimate Reality

This post is another in a series of posts on Nagarjuna and emptiness that I've been spinning out of a study I've been doing on Nagarjuna's Mulamadhyamakakarika since August (you can read other posts in the series here, here, and here). What I would like to talk about here is the "Two Truths" doctrine. Zen teachers talk occasionally about it and I have the impression that Tibetan teachers talk about it somewhat more. The idea behind the Two Truths is that reality consists of a collection of truths that are conventional in the sense of being about cause and effect in everyday life, and then ultimate truth which is about the way reality really is when you penetrate conventional reality through meditation coupled with philosophical analysis.

What the the ancient Indian philosophers who came up with the doctrine had in mind when they spoke of conventional truths were things like "if I plant this seed, a mango tree will grow and after a period of time will bear fruit". This is a clear instance of causality, namely seed -> tree -> fruit (at some point). Today, I think we could include such statements as "the intense gravitational field at the event horizon of a black hole causes the emission of virtual quantum particles when the quantum vacuum breaks down, generates a particle pair, and one particle is swallowed by the black hole while the other is emitted", a process sometimes called "Hawking radiation" because it causes black holes, previously thought not to radiate (which is why they were called "black"), to emit energy. While such statements have little or nothing to do with everyday life like mango seeds and trees (in India at least, we don't see many mango trees in Silicon Valley), they do represent a clear instance of cause and effect, and my impression is that conventional truths are basically about cause and effect.

What then is an ultimate truth? The Vedic philosophers who preceded the Buddha and continued via Brahmanism into Nagarjuna's time thought that an ultimate truth was something that would be true forever, that it was essentially immortal. And that objects that were ultimately real (hence part of ultimate reality) would have an existence from their own side, and not be dependent on causes and conditions to exist. The Vedic philosophers posited the existence of an ultimate self. The Abhidharmykas who followed the Buddha rejected the existence of an ultimate self, but posited that experience was composed of objects, called dharmas, that had ultimate existence, and that experience could be broken down into these objects, but no further. In addition, they believed that causality operated upon these objects, since they were the fundamental atoms of experience.

Nagarjuna, on the other hand, argued in the Karikas that the only statement you can make about ultimate reality is that all things are empty of any ultimate existence. His argument was based on a simple observation: if an object has ultimate existence, it can never change. Not only that, it can never interact with anything else. So the dharmas that Abhidharmykas posited couldn't possibly be subject to cause and effect and therefore either didn't exist or were subject to cause and effect and actually are part of conventional reality. Every time you try to pin down ultimate reality, you come back to emptiness: that reality is completely empty of any abiding characteristic and you cannot designate anything as ultimately real. When looking for ultimate reality, logic becomes slippery and it becomes impossible to make any statement at all about it. Chandrikirti, one of Nagarjuna's interpreters, complained about this, and many śūnyavādins (early Mayahanists who accepted emptiness as the nature of reality) were profoundly uncomfortable with the situation. 

So how does this look from 2000 years into the future?  Modern science has a different view of cause and effect than the ancient Indian philosophers. In Nagarjuna's time, cause and effect were a matter of one object somehow causing the appearance of or becoming another object. In the Karikas, Nagarjuna effectively demolishes the proposition that cause and effect can operate on ultimately real objects, establishing that the nature of reality is empty of any inherently existing objects. The modern view is that cause and effect is more a matter of events. For example, in his groundbreaking work Causality: Models, Reasoning, and Inference, Judah Pearl develops a calculus of causality grounded in Bayesian graphical network theory. The structure of the causal models he describes are all based on a graph of events with a probability on the arc between one event, the cause, and another, the effect, giving the probability that a particular cause will result in a particular effect. The probabilities are calculated using Bayes Theorem with data from observations of previous cause-effect transitions, or estimates based on models and later refined with data. Events are the stuff of experience, like the ancient dharmas, but, unlike the Abhidarmykas notion, they arise and pass away like the light of flickering fireflies on a summer night, or like the passing content of your Facebook feed, completely empty of any inherent existence. 



Image source:  angelsinnature.files.wordpress.com