Pythagoreanism

Pythagoreanism is the philosophical and religious tradition founded by Pythagoras of Samos, who established a closely knit community at Croton in southern Italy around 530 BCE combining mathematical and cosmological inquiry with an ascetic way of life, dietary restrictions, and belief in the transmigration of the soul (metempsychosis) across human, animal and even plant lives. Its central and most influential philosophical claim held that numbers and numerical ratios are the fundamental principles underlying reality, a view the Pythagoreans grounded in their discovery that musical harmony corresponds to simple numerical ratios between string lengths, which they took as evidence that the whole cosmos is ordered by number and proportion. Early Pythagorean communities were organized as much around communal discipline, secrecy and shared property as around philosophical doctrine, and the school's ideas influenced Plato directly, particularly his account of the soul's immortality and his mathematical conception of the ideal Forms in dialogues such as the Timaeus. The original Pythagorean communities declined by the early fourth century BCE amid political backlash in southern Italy, but the tradition was revived centuries later as Neopythagoreanism, a related but philosophically distinct current that fused Pythagorean number-mysticism with Platonic metaphysics in the early Roman imperial period.