When he said this, Venerable Ānanda said to the Buddha, “Sir, how is a mendicant qualified to be called ‘astute, an inquirer’?” “Ānanda, it’s when a mendicant is skilled in the elements, in the sense fields, in dependent origination, and in the possible and the impossible. That’s how a mendicant is qualified to be called ‘astute, an inquirer’.”

“But sir, how is a mendicant qualified to be called ‘skilled in the elements’?” “There are, Ānanda, these eighteen elements. The eye element, sight element, and eye consciousness element. The ear element, sound element, and ear consciousness element. The nose element, smell element, and nose consciousness element. The tongue element, taste element, and tongue consciousness element. The body element, touch element, and body consciousness element. The mind element, ideas element, and mind consciousness element. When a mendicant knows and sees these eighteen elements, they’re qualified to be called ‘skilled in the elements’.”

“But sir, could there be another way in which a mendicant is qualified to be called ‘skilled in the elements’?” “There could, Ānanda. There are these six elements: the elements of earth, water, fire, air, space, and consciousness. When a mendicant knows and sees these six elements, they’re qualified to be called ‘skilled in the elements’.”