In 1974, scholar Roger Jackson attended a lecture on karma and rebirth at the Library of Tibetan Works and Archives in Dharamsala. At one point, the teacher, the Venerable Geshe Ngawang Dhargyey, shared a story about two brothers who were reborn as fish as a result of their misdeeds toward each other. After the talk, Jackson approached the translator to ask about the story of the fish, inquiring whether it was meant to be taken symbolically. When the translator responded that it was intended to be taken literally, Jackson was stumped—and intrigued.

“As someone raised in the West with a somewhat skeptical, humanistic, scientifically informed worldview, this did not make sense to me,” he shared with Tricycle editor-in-chief James Shaheen on a recent episode of Tricycle Talks. “Yet it was clearly a central and seminal claim for these Buddhist teachers. And so I took it as a kind of koan, and over the years I’ve worked to try to understand it.”

In his new book, Rebirth: A Guide to Mind, Karma, and Cosmos in the Buddhist World, Jackson offers the first complete overview of Buddhist understandings of rebirth. In particular, he wrestles with some of the major questions surrounding rebirth: How can you be reborn without having a self? What is it that is actually reborn, and how? And can you be a Buddhist without believing in rebirth?

On Tricycle Talks, James Shaheen sat down with Jackson to discuss the practicalities of how and where one can be reborn, how understandings of rebirth have evolved over time, and how we can engage meaningfully with the concept of rebirth today. Read excerpts from their conversation below, and listen to the whole episode here.

Roger Jackson on the six realms where one can be reborn:

Traditionally, there are six realms where you can be reborn. At the bottom, there is the hell realm, which is often subdivided into many different hells. There are hot hells and cold hells, as well as occasional hells. There is a vast range of different hells that we might end up in, largely, though not exclusively, on the basis of violence committed in a particular lifetime. If you go to temples in Thailand and Sri Lanka, you’ll see wall paintings that depict the miseries of the hells, and you can see that there’s a wide range of things human beings do to end up in the hell realms.

Slightly higher up, there is the realm of hungry ghosts or unquiet spirits. This realm is connected with Indian ideas of what happens to those we know and love after they die, and it’s more closely linked to the human realm. For the most part, we don’t have knowledge of the hell realms unless we have some kind of psychic ability. But the hungry ghost realm we occasionally interact with. We don’t see them much, but there are certain times of year when we’re more likely to encounter them, and in many Buddhist traditions we leave offerings for them.

Above the hungry ghost realm, there is the animal realm. From the Buddhist standpoint, the lives of most animals are, in Hobbes’s terms, nasty, brutish, and short. They live in fear, and they constantly need to find food, to reproduce, and so forth. It’s not a good existence, even if you’re the president’s dog.

Then comes the human realm, which is not the highest in this pyramid, but it is the realm that is considered most conducive to actual spiritual progress because it’s in the human realm that we have just the right mixture of pleasure and pain. We have intelligence. We are able to actually understand our condition. And if we’re not too miserable, we can actually do something about it.

Above that, there is the asura or titan realm, which is a realm of jealous, powerful, violent gods. And at the top, there are a variety of different heavens inhabited by gods and goddesses of various types who have very long, blissful lives that are not in fact outside of samsara.

It’s entirely possible within this whole scheme to be one of the highest of the gods in one of the higher heavens and still end up down in a hell realm in your next birth because some particular karma comes up for you at the time of death. It’s a little bit like a Ferris wheel—you’re up one moment, and before you know it, boom, you’re at the bottom. Complacency is not an option.

Jackson on whether one can be Buddhist without believing in rebirth:

In the end, I don’t honestly know whether rebirth is real. I suppose this is my version of Buddhist agnosticism. Given my own skepticism about traditional arguments and perhaps traditional depictions, it seems to me that it’s quite possible to be Buddhist in a tentative way. Now, that goes against the grain of what many people think religion is all about, which is commitment and faith. It may be that this is a very pale version of Buddhism. But I think that many people in the modern world are defining themselves religiously in somewhat similar ways. This first came to me many years ago when I first discovered that I just couldn’t buy the traditional arguments for rebirth, particularly those of the seventh-century Indian philosopher Dharmakirti. I thought that if I couldn’t believe these central doctrines, I might as well be honest and just ditch the whole thing. This was after about ten years of Buddhist practice, and what I realized at that point was that I had become Buddhist in almost every other way: culturally, ritually, the way I thought about the world. I believed in the value of meditation, compassion, and examining the mind. I believed in the reality of emptiness being the nature of things. There was so much there that was so rich and that I had become part of that I just thought, “Well, how much does it matter whether I accept X doctrine?”

Granted, there are more and less crucial doctrines to a religion, but religious scholars often point out that being of a particular religion is not just a matter of adhering to certain doctrines. It’s a much larger gestalt, if you will, or an aesthetic that you participate in made up of ideas, practices, rituals, memories, conversations, arguments, and so forth. Broadly speaking, that’s what it means to be religious, and literal acceptance of a particular doctrine plays less of a part.

Jackson on the end of the world and the beginning of time:

I close the book with a passage from the Rohatissa Sutta, in which the Buddha recounts a previous life as a seer named Rohatissa. Rohatissa was able to travel through the sky and wished to find the ends of the earth. Though he traveled for a hundred years as fast as the wind, he died along the way without having reached the world’s end. In the sutta, the Buddha explains that there is no “end” to the geographic world, and instead we should be seeking the place “where one is not born, does not grow old and die, does not pass away and get reborn.” That end of the world can only be found “in this fathom-long body.” The Buddha then proclaims, “The wise one, the world-knower, who has reached the world’s end and lived the spiritual life, having known the world’s end, at peace, does not desire this world or another.” I think the Buddha is making a kind of reflexive move, saying that we may want to find out where the end of the world is, or the beginning or end of time, but that’s not the point. The place where the world begins, the place where the world ends, the place where it finds its limits is actually within you. Within your own fathom-long body is where all of this arises and all of this ceases. And if you’re going to find an end to the world, in some sense, this is where you find it: within yourself.