There isn’t one in the Christian sense. In the Therevadhan traditions the first moment of your next life (moment of conception or however it is it starts) is the next moment after the last moment of your previous life. In the later Mahayana traditions there are various ideas. Zen Buddhists don’t say much about what happens.

The Tibetans go into a lot of detail, saying that there is an intermediate state which can last up to several weeks. That’s not an afterlife though. It’s a state between one life and another where you experience very bright lights, loud sounds etc. If you open out to those you could become enlightened. But it’s not different from becoming enlightened within a lifetime.

Most people get scared and try to run away and hide from all the bright lights and sounds. That then is how they take rebirth in a new life in the Tibetan teachings.

It may sound like an afterlife, but it isn’t, it’s just temporary, between two states. Treating it like an afterlife is a bit like treating an airplane flight from one country to another as an afterlife because it is intermediate between the two countries. Or - the moment when you go through a door. As you go through a door, then there’s a shift to a new way of looking at things the other side of the door. Indeed if you go through a door you often forget things which you can recover if you go back into the room you just came out of. So in the same way going to a new life is like going through a door and the intermediate state is like that moment when you go through it. The Therevadhans think it happens instantly, isn’t even a door really. The Tibetans think in some cases it can take weeks though for others it is instant.

As for the various lives you can have, so long as it is dependent on conditions, Buddha’s insight before he became enlightened was that it is temporary and can cease. He found techniques of meditation which were thought to lead to not just peace, not just bliss, but states more refined than that, not just in this lifetime but for countless trillions of years into the future after he died. However he came to see that even the most long lived wonderful lives will end eventually. So when you read about “Buddhist realms” - none of those is an afterlife either. Even the most refined “god realms” where you are no longer even tied down to any kind of a body but just experience pure happiness or even more refined states for trillions of years - none of those are an afterlife. Because like any life, eventually it ends , through things changing, through impermanence.

And the same waking up that can happen between one life and the next can also happen in your daily life, any time, in principle. Indeed in some of the Mahayana teachings, in Zen satori and some of the Tibetan teachings, we all have tiny opportunities of awakening like that, all the time. It’s like every moment you go through an intermediate state, pass through, and enter the next moment, once your mind gets very attuned to this. Like the whole universe is fresh again after every moment. You always have this vista, this fresh start on everything, if we could but see it that way, no matter how dire your situation, it may be so stressful or painful it’s impossible for us caught up in our suffering to see but we have this in every moment.

So though there is no afterlife, there are potential moments of awakening, the nearest we have to the concept in Buddhism, present all the time, in every moment of your life.

That’s not just a feature Zen or Tibetan Buddhism. Though it is expressed a little differently, the idea that enlightenment happens now, in this life, is present in Therevadhan Buddhism also.

Walpola Rahula put it like this:

"It is incorrect to think that Nirvana is the natural result of the extinction of craving. Nirvana is not the result of anything. If it would be a result, then it would be an effect produced by a cause. It would be sankhata ‘produced’ and ‘conditioned’. Nirvana is neither cause nor effect. It is beyond cause and effect. Truth is not a result nor an effect. It is not produced like a mystic, spiritual, mental state, such as dhyana or samadhi. TRUTH IS. NIRVANA IS. The only thing you can do is to see it, to realize it. There is a path leading to the realization of Nirvana. But Nirvana is not the result of this path.You may get to the mountain along a path, but the mountain is not the result, not an effect of the path. You may see a light, but the light is not the result of your eyesight.

...

In almost all religions the summum bonum can be attained only after death. But Nirvana can be realized in this very life; it is not necessary to wait till you die to ‘attain’ it."

The four truths are understood in this way in all the main sutra traditions, Zen , Tibetan, Therevadhan, etc.

It’s a common misunderstanding of Buddha’s path that the aim is to “get out of Samsara”. But there is nowhere else to go according to his teachings. Anywhere you can go after you die, into a new life, and anywhere you can go in this life too, is dependent on whatever conditions took you from here to there. So, as Buddhists understand it, it is just like a holiday, a very long one perhaps, another life in Samsara. Some of those lives may be very blissful, last for long periods of time, but eventually your holiday ends, you die in some form and end up in another life, so you never actually really left Samsara. Not as Buddha taught.

When you awaken, you haven’t gone anywhere else. Buddha taught that he awakened already as a young man. He continued to wander through India teaching for another half century after that.

This is abundantly clear in the sutra traditions.

WHAT ABOUT A TECHNOLOGICAL SOLUTION - COULD WE NOT SOMEHOW FIND A WAY WITH TECHNOLOGY TO ACHIEVE PERFECT PERMANENT HAPPINESS IN AN INFINITE LIFE?

The Buddha's insight applies to technologically extended life too. The main question to ask yourself - “Does this depend on conditions?” Does it depend on that technology or whatever it is to keep them alive?

If so, that’s a failure point. The technology might fail so you can’t say that you are totally free of any possibility of future suffering or death.

Also, eventually the universe itself may pass away. We live in a young planet around a young star in a galaxy that still has lots of gas and dust, making new stars all the time. In all directions our universe seems very youthful. But eventually our universe too will age. We don’t know what will happen, but it will change. Some think that all matter may eventually turn to light.

Whatever happens, I see the technological futures some people sketch out of vastly extended life, if it ever happens, as a modern equivalent of the Buddhist god realms. They are described in the sutras as having tremendously long lives, countless trillion years, more than that. As long and longer as the lives of immensely long lived extraterrestrials and future humans in our science fiction.

So, if you are following the Buddhist path, such long happy lives are like a very long "holiday" - but no technology could be guaranteed to keep you happy and healthy literally forever, there'll always be ways it could fail. Even if you have to wait for degeneration of the proton or for spontaneous collapse of ordinary small pieces of matter into black holes through quantum tunneling which takes just about for ever. There will be something that could end your life.

It is worthwhile of course, to extend ones life, to find ways to be happy, and to be healthy. It’s that it is not a “happy ever after” truly, for all time. It’s not like a true “afterlife”, nor is it awakening or enlightenment.

IS THIS WHAT BUDDHA ORIGINALLY TAUGHT

The scholars who try to fit everything into the idea of some kind of a “get out of here” other state or afterlife after Buddha died have to say that the sutras have got altered since Buddha originally taught them. So could they have been?

As to whether this is how the historical Buddha actually taught, there’s a range of views on that. Some think that the Buddhist teachings were preserved at least up to the time of the Pali canon, in the same way that the ancient Indian Vedas were preserved, through memorization. The Vedas are not sacred texts at all for Buddhists. But many early Buddhists were trained as Brahmins to memorize the Vedas and so were able to memorize the Buddhist sutras using the same techniques. Others think that there’s a core of teachings from the historical Buddha which have been added to. I think those who say that they are for the most part unchanged have a very strong case myself. See Origins of the Buddhist Sutras - were they the Teachings of the Buddha? by Robert Walker on Some ideas about Buddhist teachings

All the Buddhist scholars are agreed that the Mahayana sutras were composed many centuries after Buddha died. Apart from anything else, they often refer to events that happened after he died (the Pali canon does not, not even to the radicaly changed political geography of India soon after he died which is one of the strong points in favour of them being the original teachings of the Buddha). Mahayana Buddhists are not bothered by that. Many of the traditions also have the idea that the inspriation of enlightenment continues to give rise to new teachings through to the present day, with the Zhen Buddhist koans and many Tibetan newly inspired poems and practices.

And again in both traditions, in a way it doesn’t matter that much whether Buddha taught like that. Because he taught a path that any individual practitioner can validate from their own experience. In the Kalama Sutta: To the Kalamas

“Traditions are not to be followed simply because they are traditions. Reports (such as historical accounts or news) are not to be followed simply because the source seems reliable. One's own preferences are not to be followed simply because they seem logical or resonate with one's feelings. Instead, any view or belief must be tested by the results it yields when put into practice; and — to guard against the possibility of any bias or limitations in one's understanding of those results — they must further be checked against the experience of people who are wise. The ability to question and test one's beliefs in an appropriate way is called appropriate attention. The ability to recognize and choose wise people as mentors is called having admirable friends.”

This also applies to ideas of what happens when you die. The most important thing in the Buddhist path is to keep an open mind about what you don’t know. If you don’t know what “really” happens when you die, well there is no value in trying to convince yourself you do know, to try to make yourself believe something like that because a sacred text says so, not in the Buddhist path. Indeed the starting point of wisdom in the path is to recognize clearly what you don’t know.

So the teachings are very much living things. Though the sutras are grounding and important, it’s not like we are following the teachings of someone long dead, it’s a living tradition, continually refreshed by the understanding of those who teach us (of all forms, the “wise friends” don’t have to be Buddhists) and ourselves.

So we continually validate the path ourselves in our lives, as do all the other practitioners following this path. And the path as taught in the sutras, validated in this way, is a clear one, there is nowhere else to go. We can have holidays, long periods of time when we are carefree and happy, maybe even totally blissed out, but they don’t take us to a “happy ever after” much as they may seem to at the time. The holidays always end. And the teaching, for us to look at and examine for ourselves, is that there is nowhere in the whole cycle of existence that’s a “happy ever after” endless holiday from our situation.

We have to work with our situation “as is”. The teaching is that there is a way forward, there’s the possibility of awakening, enlightenment, but that the way to seeing that, realising that, following that path, is to work with our situation right now, right here.

PURE LAND BUDDHISM

Buddhist Art and Amida Raigo Triads - Buddha Amida with two attendants coming down from the Buddhist pure land to receive the dead to enter the pure land. At least superficially, “pure land Buddhism”, which is very popular in Japan, resembles Western ideas of an afterlife. But it’s not really the same.

You may have heard of “Buddhist pure lands”. It’s popular in Japan and you have ideas like that in other traditions as well for instance again in the Tibetan traditions there’s the idea you can be reborn in a pure land.

I don’t know a lot about Japanese pure land Buddhism, but in the Tibetan tradition at least, it means to be reborn in a life where everything you see and are surrounded by inspires you with the teachings of the path to enlightenment, clarity, wisdom, compassion etc.

This doesn’t however mean you have an easy life where you are waited on hand and foot, and don’t have to do anything, and just enjoy pleasurable things for ever. It’s really much more to do with the way you relate to things than your actual surroundings.

You can find pure lands in this very world, on Earth. It’s said that some teachers in the Tibetan tradition see everything as a pure land and all beings as Buddhas. That’s hard to understand looking around this world. How could anyone possibly see all beings as Buddhas? It may not seem to make any sense.

I think this is easiest perhaps to understand by thinking that they are not tied up in time, one of the confusions that can fall away is the strictly linear way we look at time. So perhaps, they see all beings at some time awaken fully, so that’s what they are relating to. But that’s just an approximation to try to understand.

So anyway whatever it means to be reborn in a Buddhist pure land, it doesn’t mean an afterlife either. Not in the Christian sense of a “happy ever after” that you just have to get to and then all your problems are solved.

You are still on the path in a Buddhist pure land, for those who think that way, until you become enlightened.

And whether or not you follow a pure land branch of Buddhism, it is possible to relate to this very life as a pure land in that sense that you are on the path and that everything you encounter, however terrible, however sad, or however blissful and wonderful, carries the message of awakening, compassion, wisdom, and openness. So in this way the ideas of pure land Buddhism have a message for all Buddhist practitioners. You can practice like that as a Therevadhan also.

WHAT ABOUT PARANIRVANA - AFTER BUDDHA DIED DID HE NOT ENTER AN AFTERLIFE?

This is a common misconception in the West, that, ok, Buddha became awakened as a young man. But surely he entered some kind of an afterlife when he died? What else is “paranirvana”? He said that after he died he would never again take rebirth. What is that except a form of afterlife? It’s not just a popular “urban myth”. You even sometimes get Westerners writing learned tomes trying to make sense of this, trying to shoehorn it into Western ideas of an afterlife. They often end up having to say that the Buddhist teachings must have got corrupted in some way, and not present the original teachings of the Buddha because they can’t make their ideas of an afterlife consistent with the sutra teachings as accepted by all the main branches of Buddhism.

So anyway, if you go by the sutras, the recorded teachings of the Buddha, then in the context of the rest of the teachings, when he talked about “paranirvana” - he couldn’t be talking about passage into an afterlife because he taught that there is nowhere else to go. You can’t “get out of here”. Whatever it means, it can’t mean that. He made it abundantly clear that he is teaching us that, in a fundamental way, there is nowhere else to escape to, we have to face our situation here, as it is, and work with it.

According to the Pali Canon, in the The Shorter Instructions to Malunkya (the Cula-Malunkyovada Sutta), Ven. Malunkyaputta asked about what happened when he died. He asked him to say one of these things:

1. The Tathagata (a perfectly enlightened being) exists after death.
2. The Tathagata does not exist after death.
3. The Tathagata both exists and does not exist after death.
4. The Tathagata neither exists nor does not exist after death.

He said to the Buddha (according to this sutra):

"Lord, if the Blessed One … doesn't know or see whether after death a Tathagata exists... does not exist... both exists & does not exist... neither exists nor does not exist,' then, in one who is unknowing & unseeing, the straightforward thing is to admit, 'I don't know. I don't see.'"

He decided that if the Buddha didn’t answer these questions, along with other questions such as whether or not the cosmos is eternal or infinite, he would stop following the path he had set out and return to his ordinary life.

Buddha said to him:

"Malunkyaputta, did I ever say to you, 'Come, Malunkyaputta, live the holy life under me, and I will declare to you that 'The cosmos is eternal,' or 'The cosmos is not eternal,' or 'The cosmos is finite,' or 'The cosmos is infinite,' or 'The soul & the body are the same,' or 'The soul is one thing and the body another,' or 'After death a Tathagata exists,' or 'After death a Tathagata does not exist,' or 'After death a Tathagata both exists & does not exist,' or 'After death a Tathagata neither exists nor does not exist'?"

He also asks Malunkyaputta if he had ever told the Buddha that knowing the answer to these questions was a condition of him following his path.

He said "No, lord."

Buddha replied “Then that being the case, foolish man, who are you to be claiming grievances/making demands of anyone?”

He then went on and gave the analogy of someone shot by an arrow

“"It's just as if a man were wounded with an arrow thickly smeared with poison. His friends & companions, kinsmen & relatives would provide him with a surgeon, and the man would say, 'I won't have this arrow removed until I know whether the man who wounded me was a noble warrior, a brahman, a merchant, or a worker.' He would say, 'I won't have this arrow removed until I know the given name & clan name of the man who wounded me... until I know whether he was tall, medium, or short... until I know whether he was dark, ruddy-brown, or golden-colored... until I know his home village, town, or city... until I know whether the bow with which I was wounded was a long bow or a crossbow... until I know whether the bowstring with which I was wounded was fiber, bamboo threads, sinew, hemp, or bark... until I know whether the shaft with which I was wounded was wild or cultivated... until I know whether the feathers of the shaft with which I was wounded were those of a vulture, a stork, a hawk, a peacock, or another bird... until I know whether the shaft with which I was wounded was bound with the sinew of an ox, a water buffalo, a langur, or a monkey.' He would say, 'I won't have this arrow removed until I know whether the shaft with which I was wounded was that of a common arrow, a curved arrow, a barbed, a calf-toothed, or an oleander arrow.' The man would die and those things would still remain unknown to him.”

"In the same way, if anyone were to say, 'I won't live the holy life under the Blessed One as long as he does not declare to me that 'The cosmos is eternal,'... or that 'After death a Tathagata neither exists nor does not exist,' the man would die and those things would still remain undeclared by the Tathagata.”

So Buddhists in the main sutra traditions never answer that question.

In the Therevadhan schools, the “old school” based on the earliest collection of teachings of the Buddha, the Pali canon, then that’s all they say about what happens to a Buddha after death.

In the Mahayana teachings, especially in the Tibetan tradition again, then there are many stories about what happens to enlightened beings after they die, but no answers about paranirvana either.

The idea is that some Buddhas come back for life after life after they are enlightened. While others enter paranirvana. Generally the “wheel turning Buddhas” who introduce the Buddhist teachings to a world system for the first time, after the teachings have died out (or the first time ever for those teachings in a world system), like the historical Buddha, enter paranirvana after they die. Other Buddhas may return again and again.

Although Therevadhan traditions don’t have stories about Buddhas returning they do have many stories about Buddha in his previous lives as a bodhisattva (someone who devotes their lives to helping others to reach true happiness and the end of suffering) returning again and again. You can follow the bodhisattva path as a Therevadhan just as you do in other traditions; it’s one of many paths a Therevadhan Buddhist can follow.

It’s interesting that even in the Therevadhan traditions they say that not long before Buddha died, he gave strong hints to Ananda that he could choose to remain to the end of this world system. but that he needed to be asked, in order to do that. Ananda didn’t get the hint, until too late. When he finally “got” what the Buddha had been hinting, and asked him, he said it was too late, the process leading to paranirvana was already underway. They don’t go into any detail however about how it was possible for Shakyamuni Buddha to remain to the end of this world system.