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About this book

What if the things you call knowledge cannot stand up to a few careful questions?

In Plato's Theaetetus, Socrates asks a gifted young mathematician what knowledge is. The older geometer Theodorus joins them in Athens, shortly before Socrates faces the charges that will lead to his death. The question sounds simple. Finding an answer means looking closely at what it means to perceive, believe, and give a reason.

Theaetetus begins with a bold suggestion: knowledge is perception. Socrates tests the idea, drawing the young man into questions about truth and false belief. Rather than hand down answers, he acts as a midwife to another person's thoughts. You follow an argument as it takes shape, meets resistance, and demands another attempt.

What you’ll discover

  • A question worth testing Look again at what you mean whenever you say you know something.
  • Socrates as midwife Meet a questioner who helps others bring their own ideas to birth.
  • Perception under pressure Follow the claim that knowledge is perception into searching questions about truth.
  • Beyond a correct belief Explore why holding a true judgment may not be the same as knowing.
  • The demand for reasons Consider what an account must add to a belief before it becomes knowledge.

Is it for you?

This suits curious readers who like to see an argument built and pulled apart, students meeting Plato for the first time, and anyone who cares about truth. If you want firm answers at the end, you may find it frustrating.

What’s inside

The key ideas, in the 15-minute summary

  1. Socrates the midwife asks what knowledge is
  2. Perhaps knowledge is only perception
  3. Protagoras undone and the mind's own work
  4. True judgment cannot be the whole story
  5. Perhaps knowledge is true judgment with an account
  6. What the dialogue leaves behind

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Theaetetus

by Plato

Socrates and a young mathematician examine what knowledge means.

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Theaetetus by Plato, the cover

From the 15-minute summary · Key idea 1 of 6

Socrates the midwife asks what knowledge is

The dialogue opens with a frame. Two men, Euclides and Terpsion, meet in Megara and speak of Theaetetus, who has been carried home from an army camp near Corinth, wounded and ill. Euclides says he once wrote down a conversation that Socrates had with the boy long ago, and a slave now reads it aloud. That written conversation is the rest of the book.

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The author

Plato

428 BC–348 BC · Ancient Greek philosopher

4th-century BCE Greek philosopher.

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What is Plato's Theaetetus about?

It asks what knowledge is. Socrates and the young mathematician Theaetetus test three answers: knowledge as perception, as true judgment, and as true judgment with an account. Each answer is examined and found lacking.

Who is Theaetetus in the dialogue?

He is a gifted young Athenian mathematician, a real person known for work on irrational roots. Plato shows him as quick, modest and brave in argument, and the dialogue is named in his honor.

What does Socrates mean by being a midwife?

Socrates says his mother was a midwife and that he does the same work for ideas. He does not give birth to ideas himself but helps others bring theirs out and checks whether they are sound.

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