I'm trying to understand how modern Buddhism deals with our current scientific understanding.

Science indicates that life began on this planet with a small set of life forms. So there was a point in time where only a few life forms would be capable of rebirth. Now, however, there are over 7 billion humans and immensely more other creatures which can all be reborn. Where did all the souls/consciousnesses that exist now come from? How does the idea of rebirth fit with the evolution of life on Earth?

I am very curious as to how modern Buddhism deals with this question. Please forgive me if it is a dumb question, my understanding of Buddhism is very minimal. Thanks in advance!

  • This question might be a duplicate or is nearly a duplicate of "Why is human population increasing? Better kamma?" isn't it? Or it may be a duplicate of some of the topics with the evolution tag ... but I think this question is asking, "if science tells us that the number of sentient beings has increased since the time when life began on earth, does that contradict modern Buddhist doctrine of rebirth"?
    – ChrisW
    Commented Mar 11, 2016 at 2:35
  • 1
    Yes I mean the latter, something more like "if the number of sentient beings has increased, where do the increased souls come from?" I seek to understand how Buddhists answer this. I'm sure I'm not the first to ask this, but I didn't find an answer on this site yet or in the links you posted.
    – M47145
    Commented Mar 11, 2016 at 3:09
  • Check out an explanation with some math analysis here: dhammawheel.com/…
    – santa100
    Commented Mar 12, 2016 at 2:27
  • @santa100 Thanks I checked it out. However, if the number of beings is infinite as the answer below suggests, then it would render the chances of a being ascending and descending between planes irrelevant.
    – M47145
    Commented Mar 12, 2016 at 3:08
  • Irrelevant as a whole but relevant since you mention eartch specifically. Also the chances are actually relevant per the famous "blind turtle hitting the log in the ocean" sutta.
    – santa100
    Commented Mar 12, 2016 at 5:07

2 Answers 2


There are an infinite number of beings in all the places of existance and also an infinite number of universes. The earth being one of the humanoid worlds. [Kosala Sutta 1] In some of the higher planes the number of beings are finite. In lower planes this might not be the case. As life span decreases the merit required to be born in the human plane decreases hence the population increase. Sometimes conflicts and natural disasters do reduce the population.

Aggañña Sutta does mention about evolution from being in higher plane and how the deteriorate incidentally occupying the lower planes. (At the start of the cycle there only a higher plane)

Their body was still coarse and roughly shaped. Thus, after a very long time, the mud-like substance began to be exhausted. Then, mushroom-like plants began to grow so fast that they replaced the mud-like ocean. The creatures began to devour them as well, and they also found it delicious, like sweet honey and milk. Their body hardened more and details began to turn finer.

After another very long time, the mushrooms also began to be exhausted, replaced by cassava or turnip-like plants. They also began to devour them night and day, and thus they began to notice differences amongst them. As the changes of their bodies varied between each other, the concept of difference arose. The concepts of the beautiful and the ugly were born. The beautiful scorns the ugly and they became arrogant because of their appearance.

Sourced from: Aggañña Sutta

Also see:

  • Thank you for your detailed response! It is very helpful. I wish to clarify one thing if I may. So there are infinitely many beings, and our universe has only a finite number of beings. What happens when the population of our universe increases? If I understand you correctly, the beings from other universes can cross into ours to compensate for population growth. Is this correct?
    – M47145
    Commented Mar 11, 2016 at 4:51
  • Our universe may have finite number of beings (but I believe each universe has infinite beings also as nothing is said about the number of beings in lower realms) but also there are infinite parallel universes. So Inf + n = Inf, Inf - n = Inf. Commented Mar 12, 2016 at 14:00

According to Buddhism, life began on this planet with a small set of beings too. Actually, it was just one being to start with. One of the oldest Brahmas from the Abhassara Brahma realm who descended to earth after his life span ran out. He was mind-made, feeding on delight, self-luminous, moving through the air, glorious.

After living alone for a long time, he started to think that it would be better if there were other beings like him on earth. Then other beings who passed away on Abhassara realm, started to appear on earth too. This made the original being think that these new beings were created due to his wishing. This is the origin of the beliefs like "God created man in his image".

As the beings started descending from other worlds, the population increased and the appearance of those beings started to change as time passed by. More details can be found in Agganna Sutta. So there are similarities to evolution theory, but Buddhism doesn't subscribe to the scientific view that life originated on earth due to chemical reactions.

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