Cosmic time: How long is an aeon (kalpa)?

Dhr. Seven, Pat Macpherson, Wisdom Quarterly

Finally, to suggest that the Buddha may have known what he was talking about, thousands of years ago he was asked to define an "aeon," a kalpa.

His practical answer suggests he was defining a great aeon, an unimaginable length of time, the duration of a universe or longer. We cannot imagine such timespans, except that now science throws around the idea of our universe being 13 billion years or more (given that older light is sometimes spotted by new space telescopes like Hubble and that newest one). How does a teacher of Truth begin to define a thing that cannot be imagined? He uses his imagination to stagger his audience with the otherwise inconceivable. The Buddha answered by saying:

• Imagine a piece of flawless marble or granite one yojana (seven miles) long, one yojana tall, and one yojana wide. Now further imagine a person coming by every hundred years and wiping this great mass of flawless stone without crack or crevice with a piece of soft Kasi cloth (the finest muslin). That entire mass of rock would be worn down to nothing, and yet a single kalpa would still not have elapsed ("The Mountain," Pabbata Sutta, SN 15:5, Dhr. Seven translation).

The strange thing about Sanskrit and Pali terms is that, while kalpa means "aeon," it can also mean "lifespan" and so be as short as one human lifespan, which is variable duration between 80,000 years and less than 120. At that time, females reach puberty after 500 years. (But here "500" does not really mean a literal half of a millennium. It means "many," like when we in modern American English hyperbolically say, "There was a million of them" and there was nowhere near an actual million (as in acne pustules on a teenager's face) or there were many more than a million, but we stopped counting (as with the number of stars visible in the night sky not beset by light pollution).

That is not all the Buddha said because he was making a point about the insidious nature of rebirth. We all want to live, to pursue new stimuli and indulge in sensual pleasures, so much so that we cling to life, but we eventually die. This unsatisfied craving -- which can never be satisfied except that we think, "Oh, sure it can, with the next thing," because each thing obtained ultimately disappoints -- engenders another rebirth. How many rebirths? Countless, too many to count, because it's been going on for unimaginable kalpas. So the Buddha made his point: 

"And we have all wandered on through many such aeons -- many hundreds, many thousands, many hundreds of thousands of them. Why? Birth has no known beginning.

"Long enough has one experienced disappointment, experienced pain, experienced loss, swelling up the cemeteries, long enough to become disenchanted with all things, long enough to become dispassionate, long enough to be free [of clinging to] all things." Let go and be free.

• See SN 15:5  Pabbata Sutta | "A Mountain" (dhammatalks.org)