Aṅguttara Nikāya
4. Book of the Fours
77. Unconjecturable
“There are these four unconjecturables that are not to be conjectured about, that would bring madness & vexation to anyone who conjectured about them. Which four?
“The Buddha-range of the Buddhas is an unconjecturable that is not to be conjectured about, that would bring madness & vexation to anyone who conjectured about it.
“The jhana-range of a person in jhana...
“The [precise working out of the] results of kamma...
“Conjecture about [the origin, etc., of] the world is an unconjecturable that is not to be conjectured about, that would bring madness & vexation to anyone who conjectured about it.
“These are the four unconjecturables that are not to be conjectured about, that would bring madness & vexation to anyone who conjectured about them.”