Plutarch De Iside et Osiride 56

[56] The better and more divine nature consists of three parts: the conceptual, the material, and that which is formed from these, which the Greeks call the world. Plato ¹ is wont to give to the conceptual the name of idea, example, or father, and to the material the name of mother or nurse, or seat and place of generation, and to that which results from both the name of offspring or generation.

One might conjecture that the Egyptians hold in high honour the most beautiful of the triangles, ² since they liken the nature of the Universe most closely to it, as Plato in the Republic ³ seems to have made use of it in formulating his figure of marriage. This triangle has its upright of three units, its base of four, and its hypotenuse of five, whose power is equal to that of the other two sides. ⁴ The upright, therefore, may be likened to the male, the base to the female, and the hypotenuse to the child of both, and so Osiris may be regarded as the origin, Isis as the recipient, and Horus as perfected result. Three is the first perfect odd number: four is a square whose side is the even number two; but five is in some ways like to its father, and in some wrays like to its mother, being made up of three and two. ⁵ And panta (all) is a derivative of pente (five), and they speak of counting as numbering by fives. ⁶ Five makes a square of itself, as many as the letters of the Egyptian alphabet, and as many as the years of the life of the Apis.

Horus they are wont to call also Min, which means seen; for the world is something perceptible and visible, and Isis is sometimes called Muth, and again Athyri or Methyer. By the first of these names they signify mother, by the second the mundane house of Horus, the place and receptacle of generation, as Plato ⁷ has it, and the third is compounded of full and cause; for the material of the world is full, and is associated with the good and pure and orderly.

[56] Now the better and more divine nature consists of three; or of the intelligible part, of matter, and of that which is made up of both, which the Greeks call Cosmos (that is trimness) and we the world. Plato therefore uses to name the intelligible part the form, the sample, and the father; and matter the mother, the nurse, and the seat and receptacle of generation; and that again which is made up of both, the offspring and the production. And one would conjecture that the Egyptians called it the most perfect of triangles, because they likened the nature of the universe principally to that; which Plato also in his Commonwealth seems to have made use of to the same purpose, when he forms his nuptial diagram. Now in that triangle the perpendicular consists of three parts, the base of four, and the subtense of five, its square being equal in value with the squares of the two that contain it. We are therefore to take the perpendicular to represent the male property, the base the female, and the subtense that which is produced by them both. We are likewise to look upon Osiris as the first cause, Isis as the faculty of reception, and Horus as the effect. For the number three is the first odd and perfect number, and the number four is a square, having for its side the even number two. The number five also in some respects resembles the father and in some again the mother, being made up of three and two; besides, πάντα ( all things) seems to be derived from πέντε ( five) and they use πεμπάσασθαι (which is telling five) for counting. ¹ Moreover, the number five makes a square equal to the number of letters used among the Egyptians, as also to the number of years which Apis lived. They are also used to call Horus Min, which signifieth as much as seen; for the world is perceptible to sense and visible. And Isis they sometimes call Muth, and sometimes again Athyri, and sometimes Methyer. And by the first of these names they mean mother, by the second Horus’s mundane house (as Plato calls it, the place and receptacle of generation); but the third is compounded of two words, the one whereof signifies full, and the other the cause; for the matter of the world is full, and it is closely joined with the good and pure and well ordered principle.