I don’t know... I’m a Pragmatic Buddhist and so I accept verifiable knowledge if it can fall into at least one of three types of evidence: personal experiential knowledge, cross-cultural social consensus or the testimony of appropriate authority. If you’ve looked into Pragmatism you’ll notice that I have added a couple of qualifiers to this list. I insist that social consensus exist not just within my cultural milieu but across cultures. I also use a qualifier of ‘appropriate’ to the testimony of authority. We must be sure that the authorities who are offering testimony are qualified to offer truthful testimony. For example, I would not accept - without other verification - the testimony of a biologist about matters of cosmology.
I have no experience of rebirth. No universal social consensus exists around whether it exists or not - most opinions are definitely culture-bound on this one. What about the testimony of appropriate authority? That’s a thorny question.
Who is an appropriate authority on rebirth? Some would point to the Dalai Lama as the reincarnation of the Bodhisattva Avallokitesvara but - with all due respect to a great leader - all of the evidence for that is culture-bound consensus. Others - especially in the Theravada community - point to the Jataka Tales in the Pali Canon as showing evidence of the prior births of Gautama Buddha; but I have a difficult time with that testimony as - even accepting them as direct testimony of the Buddha (which is far from universal consensus) - they form only a circular argument on authority. “I am an appropriate authority because I say I am an appropriate authority” is not a valid argument.
As I Pragmatist and a Pragmatic Buddhist I have no option but to say, “I don’t know…”. While I am not able to say we will be reborn I’m also hesitant to say we won’t since I have no way of verifying that either. Does this make me any less of a Buddhist? I would argue no since - even if we strip out the consequence of a round of rebirths - all of the teachings of the Buddha revolve around what do we need to do in this life to be liberated from dukkha, from unsatisfactoriness, whether that dukkha passes over multiple lives or just one. I am still a follower of the Dharma and a traveler on the Buddha Way - no matter how much I may stumble.
Notice though that I end my answer with an ellipsis. What I left out is, “but does it matter?” Why do we care as Buddhists - or those seeking to learn more about Buddhism, or simply as human beings - if we will be reborn or not? After all, even if we accept rebirth the whole thrust of the message of the Buddha is on how we can be liberated from this cycle of birth/dukkha/death/rebirth; and that ‘how’ must be acted on in this life. Here. Now.
It matters not at all if we’re looking at a cyclical existence as above or if existence ends at death; the focus of our life is the cessation of dukkha. The focus of our life is ceasing to do harm, doing good and doing good for others. The Buddha even addresses this directly in the Kalama Sutra when he tells the people of the Kalamas that the reason they should be interested in doing what is right, skillful and compassionate is that:
"'If there is a world after death, if there is the fruit of actions rightly & wrongly done, then this is the basis by which, with the break-up of the body, after death, I will reappear in a good destination, the heavenly world.' This is the first assurance he acquires.
"'But if there is no world after death, if there is no fruit of actions rightly & wrongly done, then here in the present life I look after myself with ease — free from hostility, free from ill will, free from trouble.' This is the second assurance he acquires.”
He does not tell them to act in hopes of a better rebirth, or of none at all. He tells them that it doesn’t matter if there is rebirth or not!
This is the message of the Buddha: What may come after this life - or not come - is of no importance. Only what you do IN this life is important. All the stories about previous lives are nothing but phantasms whose only importance is in the lessons they have to teach about the ways we should behave in this life. It doesn’t matter if these stories are the actual words of the Buddha or stories that were added to give life to the principles he taught. It doesn’t even matter whether they are true or only skillful means that the Buddha was using to illustrate this point to a people who believed in reincarnation. In the Atthakavagga the Buddha teaches:
Just as a person awakening does not see those things they met in dreams; so a beloved person will no longer be seen when they have died.
We can see and hear the people we call by name; yet only the name remains of those who have died.
This is just as true of possible past lives as it is of people who have died in this life.
If the past can be a prison to us, keeping us from focusing on what needs to be done in this life; so too is the future. If we spend our life worried about our possible future rebirth(s) we will never be content in this world. We will never lose our attachment to existence and to our ego. In another passage in the Atthakavagga the Buddha says of those who have found peace, “With no attachment to the future the person at peace does not sorrow for the past. They view their contacts with dispassion and are not confined to any one philosophy.” This is our goal, our task: to neither cling to past nor future but to live in the present moment as if it were the only moment in which we can act - because it is.
To your question I can only say I don’t know…but why does it matter?