Philosophy › Socrates, Plato, Aristotle & the Axial Age
Plato
c. 428–348 BC· Philosopher· Reality, mind & God
Well documentedSolid records, texts or physical evidence.
Athenian philosopher, Socrates' student and Aristotle's teacher, whose dialogues set most of the agenda for Western philosophy.
See it on the Philosophy map →The idea
Born into an aristocratic Athenian family around 428 BC, he followed Socrates until the execution of 399 BC, then travelled, meeting Pythagoreans in southern Italy. Around 387 BC he founded the Academy, a school that lasted about three centuries. He wrote some 35 dialogues, mostly starring Socrates, arguing that true reality is unchanging Forms, the soul is immortal, and philosophers should rule. Two trips to Syracuse to train its young ruler as a philosopher-king failed.
Why it matters
Nearly every later debate on reality, knowledge, ethics, politics, love and art starts from his questions; Whitehead called European philosophy 'a series of footnotes to Plato.'
Legacy and sources
Unusually, his complete works survive, copied through antiquity and Byzantium. Aristotle and later biographers add details; some letters and minor dialogues may not be his.
Still debated
How much of the 'Socrates' in the dialogues is the real man and how much is Plato, and whether Plato taught unwritten doctrines.
Inside this (6)
Connections (8)
▸Pythagoras and the Pythagoreans inspired PlatoMostly agreed
The connection
Plato took from the Pythagoreans the belief that mathematics reveals the hidden order of reality, that the soul is immortal and reborn, and that philosophy is a disciplined way of life. His Timaeus builds the elements from geometric triangles, and his Republic makes years of mathematics required training for rulers.
When and how
Around 388 BC Plato visited southern Italy and befriended Archytas of Tarentum, a leading Pythagorean statesman and mathematician.
How sure are we?
Aristotle (Metaphysics I.6) says Plato followed the Pythagoreans in most things; Pythagorean themes run through the Phaedo, Republic and Timaeus.
Debates and open questions
Pythagoras left no writings, so separating his own ideas from later Pythagoreans, and from Plato's reworking of them, is very hard.
▸Socrates taught PlatoWell documented
The connection
Plato joined Socrates' circle as a young man and absorbed his method of relentless questioning and his focus on how to live. After the execution he made Socrates the hero of nearly all his dialogues, at first recreating his style, later putting his own theories, like the Forms, into Socrates' mouth.
When and how
Athens, roughly 408–399 BC, when Plato was in his twenties. He was at the trial, offering to help pay a fine, but missed the death through illness.
How we know
Plato names himself at the trial in the Apology and as absent in the Phaedo; Xenophon and Aristotle also place him among Socrates' followers.
Debates and open questions
The 'Socratic problem': which views in the dialogues belong to the historical Socrates and which to Plato. Xenophon's Socrates is plainer and more practical.
▸Plato taught AristotleWell documented
The connection
Aristotle arrived at Plato's Academy at 17 and stayed 20 years, first as student, then as teacher. He kept Plato's goal, real knowledge of universal truths, but grounded it in observation of this world. In his Ethics he notes that friends are dear, but truth must come first, even against Plato's ideas.
When and how
Athens, 367–347 BC. When Plato died, leadership of the Academy passed to his nephew Speusippus, and Aristotle left the city.
How we know
Ancient biographies, chiefly Diogenes Laertius, give the dates; Aristotle's works constantly discuss Plato's views, sometimes saying 'we' of the Platonists.
Debates and open questions
How much of Aristotle's system took shape while he was still a Platonist, and whether his break with Plato was early or gradual, is debated.
▸Plato proposed Plato's theory of FormsWell documented
The connection
Plato built the theory from Socrates' search for definitions: if courage or beauty can be defined, there must be one stable thing the definition captures. He argued that these things, the Forms, exist apart from the changing physical world and are grasped by reason, then tested the theory in later dialogues.
When and how
Athens, in middle-period dialogues written around 385–370 BC, chiefly the Phaedo, Symposium and Republic, then criticized in his Parmenides.
How we know
The dialogues state the theory repeatedly, and Aristotle, who studied under Plato for 20 years, attributes it to him and criticizes it in detail.
Debates and open questions
Aristotle says Socrates sought definitions but never made them separate things; whether that step was Plato's alone, and how reliable Aristotle's report is, is debated.
▸Plato wrote Plato's RepublicWell documented
The connection
Plato wrote the Republic in mid-career as a long Socratic conversation that pulls his ideas together: justice, the soul's three parts, the Forms, education, the philosopher-ruler, and the decline of governments. Socrates narrates, but the system is generally read as Plato's own.
When and how
Athens, around 375 BC, about a decade after he founded the Academy; the conversation is set in Piraeus, the port, during the Peloponnesian War.
How we know
Its authenticity has never been seriously doubted; Aristotle's Politics discusses it by name, and studies of Plato's style place it in his middle period.
Debates and open questions
Book I differs in style from the rest and may first have been a separate dialogue; the exact date of composition is unknown.
▸Plato was reworked by Plotinus and NeoplatonismWell documented
The connection
Plotinus saw himself as simply explaining Plato. He took the Republic's Form of the Good, 'beyond being', and the One of the Parmenides, and made them a single first principle from which Mind, Soul and matter flow. Plato's split between Forms and world became a graded ladder.
When and how
Rome, AD 244–270, about 600 years after Plato; edited by Porphyry as the Enneads.
How we know
The Enneads constantly quote and interpret Plato's dialogues, especially the Timaeus, Republic, Parmenides and Symposium.
Debates and open questions
Whether Plotinus faithfully developed Plato or built a new system is debated; the label 'Neoplatonist' was coined by modern scholars, not used by him.
▸Plato led, via the Academy, to one branch of Ancient Skepticism (Pyrrho to Sextus Empiricus)Mostly agreed
The connection
Plato's dialogues often end without answers, and his Socrates claims to know nothing. Around 266 BC Arcesilaus, the Academy's new head, made that side of Plato central: argue both sides, assert nothing. For two centuries Plato's own school was the leading skeptical school, attacking Stoic claims to certainty. Pyrrhonism grew separately, from Pyrrho.
When and how
Athens, about 266–90 BC, under Academy heads Arcesilaus and Carneades; Aenesidemus later left the Academy to revive Pyrrho's stricter skepticism.
How sure are we?
Cicero, who studied with Academic skeptics, describes the lineage in his Academica; Sextus Empiricus carefully distinguishes the Academics from the Pyrrhonists.
Debates and open questions
Was Arcesilaus faithful to Plato, who clearly believed in Forms, or did he redirect the school? Ancient and modern readers disagree.
▸Plato answered "Beauty itself, a Form" to What is beauty? The question of aestheticsMostly agreed
The connection
In the Symposium, the wise woman Diotima describes a ladder of love: from one beautiful body to all bodies, then to beautiful souls, laws and knowledge, and finally to Beauty itself, eternal and unchanging. For Plato beauty is objective, not in the eye of the beholder. Yet in Republic Book X he distrusts art as a copy of a copy.
When and how
Athens, around 385–375 BC, in the Symposium and the Republic; the Symposium is set at a drinking party in 416 BC.
How sure are we?
The Symposium (210a–212a) states it plainly; Plotinus's essay 'On Beauty' (c. AD 250s) and Renaissance Platonists carried it forward.
Debates and open questions
How Plato squared beauty's high value with his hostility to poets and painters, and whether objective beauty survives Hume's and Kant's turn to taste.