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Portrait of Cicero
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Cicero

Marcus Tullius Cicero

Roman statesman who gave Latin its philosophical vocabulary and preserved Greek thought.

Academic SkepticismRomanRoman106–43 BCE◦ Arpinum, Latium2nd century BCE

Overview

Rome's greatest orator and a leading statesman (consul in 63 BCE), Cicero was philosophically an Academic skeptic who weighed the arguments of every school. In an extraordinary late burst of writing he rendered Greek philosophy into Latin — coining much of the West's philosophical vocabulary — and defended natural law, moral duty, the republic, and a reasoned approach to religion. His works became the main channel through which ancient philosophy reached the Middle Ages and Renaissance. He was killed in the proscriptions of 43 BCE for opposing Mark Antony.

What they supported — and why

Academic probabilism

SupportedAdopt the most probable view after weighing all sides, without claiming dogmatic certainty.

WhyNo school proves its case beyond doubt, so the wise course is to follow the likeliest argument while remaining open.

Natural law and duty

SupportedThere is a true, universal law of reason above human statutes, from which our duties (officia) derive.

WhyReason is shared by gods and all humans, so it grounds a justice and obligation binding everywhere and always.

The mixed constitution

SupportedA balance of monarchic, aristocratic, and popular elements best secures liberty and stability.

WhyPure constitutions decay into their corrupt forms; mixing them checks each against the others.

Causes championed

  • The Roman republic and its liberty
  • Natural law and universal justice
  • Reasoned tolerance among the schools
  • Philosophy written in Latin

Issues wrestled with

  • What are justice and law?
  • How should we live, age, and die?
  • What can we know of the gods?

Hurdles faced

  • Political exile and the collapse of the republic he loved
  • Assassinated for his speeches against Antony

Works & books

6 catalogued. Status shows how much survives to today.

On Duties

Survives

De Officiis

His influential treatise on moral obligation and practical ethics.

On the Nature of the Gods

Survives

De Natura Deorum

A dialogue weighing Stoic, Epicurean, and skeptical views of religion.

On the Republic & On the Laws

Partial

Political philosophy on the best constitution and on natural law; the Republic survives partly (including the Dream of Scipio).

Tusculan Disputations

Survives

Five books on death, pain, grief, and how virtue secures happiness.

Academica; On the Ends of Good and Evil

Survives

Surveys of epistemology and of the schools' theories of the highest good.

On Old Age; On Friendship

Survives

Beloved short essays on aging well and on friendship.

Read the texts free

14 of Cicero’s works are free to read in full — public-domain English editions on Project Gutenberg, matched from Gutenberg’s own catalogue.

Every edition online — Open Library catalogues 3,502 works & editions, 642 of them free to read in full.

Influenced by

Plato and the AcademyPanaetiusPosidoniusPhilo of Larissa

Influenced

AugustineAquinasRenaissance humanistsLocke and Jeffersonthe natural-law tradition

In their words

“The good of the people is the highest law.”

— De Legibus

“To live is to think.”

— Tusculan Disputations

Legacy

More than anyone, Cicero carried Greek philosophy into the Latin West; for centuries, to study philosophy in Europe meant to read Cicero.

Further reading

Cross-checked against these authoritative references.

Authority records

Linked into the wider knowledge graph via Wikidata — the stable spine other sources hang off.