Pentad (Greek philosophy)
The pentad was a Pythagorean term for the number five. A pentagram, symbol of the pentad, was used by the Pythagoreans as a secret sign to recognize each other. It represents the number five, life, power and invulnerability. Nicomachus explored the mathematical characteristics of the pentad as related to the Pythagorean saying "Justice is five".
The Nicomachean extracts reads:
"The pentad is change of quality, because it changes that which is triply extended or which has length, breadth and depth into the sameness of a sphere"
See also
Pythagoreans symbols
- Monad (Greek philosophy)
- Dyad (Greek philosophy)
- Triad (Greek philosophy)
- Tetrad (Greek philosophy)
- Decad (Greek philosophy)
Related
- Iamblichus of Chalcis
- Pentagram
- Vesica pisces
Sources
- Hemenway, Priya. Divine Proportion: Phi In Art, Nature, and Science. Sterling Publishing Company, Inc., 2005. ISBN 1-4027-3522-7
- O'Meara, Dominic J. Pythagoras Revived: Mathematics and Philosophy in Late Antiquity. Clarendon Press, 1990. ISBN 0-198-23913-0