🧠Greek Philosophy Unit 3 – Pythagoras: Math and Philosophy

Who Was Pythagoras?

• Ancient Greek philosopher and mathematician born around 570 BCE on the island of Samos
• Traveled extensively, including to Egypt and Babylon, where he studied with priests and scholars
• Founded a philosophical and religious school in Croton, southern Italy around 530 BCE
• Believed in metempsychosis, the transmigration of souls, and followed a strict vegetarian diet
• Emphasized the importance of mathematics, music, and astronomy in understanding the universe
• Credited with the discovery of the mathematical relationship between musical intervals and numerical ratios
• Considered a mystic and a spiritual leader by his followers, who adhered to a strict code of secrecy and communal living

The Pythagorean School

• Also known as the Pythagorean Brotherhood, a philosophical, religious, and scientific community
• Established by Pythagoras in Croton, southern Italy, attracting intellectuals and aristocrats
• Members lived communally, shared property, and followed a strict code of conduct and dietary restrictions
  • Vegetarianism was practiced, as Pythagoras believed in the transmigration of souls
  • Secrecy was maintained about the school's teachings and discoveries
• Studied various subjects, including mathematics, music, astronomy, and philosophy
• Believed in the concept of "harmony of the spheres," the idea that celestial bodies produce music
• Influenced by Orphism, a mystical and ascetic religious movement in ancient Greece
• School declined in influence after Pythagoras' death and the persecution of Pythagoreans in Croton

Mathematical Discoveries

• Pythagoreans made significant contributions to mathematics, particularly in geometry and number theory
• Credited with the discovery of irrational numbers, such as the square root of 2
  • This discovery challenged the Pythagorean belief that all numbers could be expressed as ratios of integers
• Developed the concept of perfect numbers, which are equal to the sum of their proper divisors (e.g., 6 = 1 + 2 + 3)
• Investigated the properties of figurate numbers, such as triangular and square numbers
• Explored the relationships between numbers and geometric figures, leading to the development of mathematical proofs
• Contributed to the understanding of the five regular polyhedra (tetrahedron, cube, octahedron, dodecahedron, icosahedron)
• Laid the foundation for the study of number theory and abstract mathematics in ancient Greece

Philosophical Ideas

• Pythagoras and his followers believed in the fundamental role of numbers in understanding the universe
• Considered numbers to be the ultimate reality and the basis of all things
• Developed the concept of the "music of the spheres," the idea that celestial bodies produce harmonious sounds
• Emphasized the importance of the soul and its immortality, believing in metempsychosis (transmigration of souls)
• Promoted the idea of a harmonious and ordered universe, governed by mathematical principles
• Believed in the duality of opposites (e.g., odd and even, limited and unlimited) and their role in creating harmony
• Emphasized the importance of living a virtuous life, following a strict moral code, and pursuing wisdom
• Influenced later Greek philosophers, such as Plato, who incorporated Pythagorean ideas into his own philosophy

The Pythagorean Theorem

• States that in a right-angled triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides
• Expressed mathematically as: $a^2 + b^2 = c^2$, where $c$ is the hypotenuse and $a$ and $b$ are the other two sides
• One of the most famous and widely used mathematical theorems in history
• Provides a fundamental relationship between the sides of a right-angled triangle
• Has numerous applications in various fields, including architecture, engineering, and navigation
• Pythagoreans provided the first known proof of the theorem, although it may have been known earlier in other cultures
• The theorem bears Pythagoras' name, although the extent of his personal contribution to its development is uncertain

Influence on Greek Thought

• Pythagorean ideas had a profound impact on later Greek philosophers and scientists
• Plato, in particular, was heavily influenced by Pythagorean thought
  • Incorporated the idea of mathematical forms as the basis of reality into his philosophy
  • Emphasized the importance of harmony, proportion, and order in the universe
• Aristotle, while critical of some Pythagorean ideas, acknowledged their contributions to mathematics and philosophy
• Pythagorean concepts of harmony and proportion influenced Greek art and architecture
  • The golden ratio, closely associated with the Pythagoreans, was used in the design of buildings and sculptures
• The Pythagorean emphasis on the study of numbers and their properties laid the foundation for the development of number theory
• Pythagorean ideas about the nature of the universe and the role of mathematics in understanding it influenced later Greek cosmological theories

Legacy and Modern Relevance

• Pythagoras and the Pythagorean school left a lasting legacy in mathematics, philosophy, and science
• The Pythagorean theorem remains a fundamental concept in mathematics and has numerous practical applications
• Pythagorean ideas about the importance of mathematics in understanding the universe influenced the development of mathematical physics
• The concept of the "music of the spheres" inspired later astronomers and philosophers, such as Johannes Kepler
• Pythagorean vegetarianism and belief in the transmigration of souls influenced later philosophical and religious movements
• The Pythagorean emphasis on the study of numbers and their properties laid the foundation for modern number theory
• Pythagorean ideas about harmony, proportion, and order continue to influence art, architecture, and design
• The Pythagorean school's approach to communal living and the pursuit of knowledge has inspired various intellectual communities throughout history

Key Takeaways

• Pythagoras was an ancient Greek philosopher and mathematician who founded the Pythagorean school in southern Italy
• The Pythagorean school made significant contributions to mathematics, particularly in geometry and number theory
• Pythagoreans believed in the fundamental role of numbers in understanding the universe and emphasized the importance of harmony and proportion
• The Pythagorean theorem, stating the relationship between the sides of a right-angled triangle, is one of the most famous mathematical concepts
• Pythagorean ideas influenced later Greek philosophers, such as Plato and Aristotle, and had a lasting impact on art, architecture, and science
• The legacy of Pythagoras and the Pythagorean school can be seen in various fields, from mathematics and physics to philosophy and design
• Pythagorean concepts, such as the "music of the spheres" and the emphasis on the study of numbers, continue to inspire and influence modern thinkers