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8 From Moderatus the Pythagorean
Arith.8 · Wachsmuth pp. 21
Number, to give a general description, is a system of monads, or the forward progression of a multitude beginning from a monad and a backward progression ending in a monad. Monads set a limit to quantity: as the multitude is diminished by subtraction, this quantity, stripped of every number, reaches a state of rest and stands still. For the monad cannot move backward any farther along the scale of quantity. It was therefore reasonably called a “monad,” either because it stands still and remains unchanged, always in the same condition, or because it has been separated from the multitude and left altogether alone.23
9 ⟨The same author⟩
Arith.9 · Wachsmuth pp. 21
Some declared the monad to be the beginning of numbers, but the One the beginning of things that are numbered. The latter is a body divisible without limit; thus things that are numbered differ from numbers in the same way that bodies differ from incorporeal things. We should also know that, as principles of numbers, later thinkers introduced the monad and the dyad, whereas the Pythagoreans introduced the successive setting out of all the terms through which even and odd are understood.24
10 ⟨Plutarch⟩
Arith.10a · Wachsmuth pp. 21-22
Pythagoras devoted the greatest care to numbers, referring both the generation of living beings and the revolutions of the stars to them. He also named numbers by likening them to the gods: the monad was Apollo, the dyad Artemis … the number six Marriage and Aphrodite, seven the Opportune Moment and Athena, eight Poseidon the Steadfast, and ten All-Completeness.25
10 continued
Arith.10b · Wachsmuth pp. 22
As for number itself, he declared the even incomplete, but the odd full and complete. For when odd is combined with even, it always makes the odd result prevail; and when added to itself, it generates even, whereas even never generates odd, since it is neither fertile nor endowed with the power of a beginning. Thus, when divided in two, many even numbers resolve into odd numbers, such as six and ten; but no odd number resolves into even numbers. For the beginning and element cannot be divided into other things; all the other things, however, resolve into the same constituents.26
10 continued
Arith.10c · Wachsmuth pp. 22
Moreover, when successive odd gnomons are placed around the monad, the number produced is always square. When even gnomons are placed around it in the same way, all the resulting figures are oblong and unequal-sided; none is an equal number taken an equal number of times. And when the numbers are divided into two equal groups, an odd number has a monad left over in the middle; in an even number the middle is left empty, unoccupied, and unnumbered, as though the number were deficient and incomplete. This is how he sets out the general account of numbers.27