Treatise on Tolerance
Written on the occasion of the death of Jean Calas, the treatise reconstructs the Toulouse affair, then argues from history, natural law and civic utility that persecuting people for their beliefs is as cruel as it is absurd. Toward its end, a prayer to the God of all beings asks humans to bear with one another.
Understanding the text
Jean Calas, a Protestant merchant, was executed in 1762 after being accused of killing his son to prevent his conversion. Published in 1763 within Voltaire’s campaign, the treatise contributed to the rehabilitation of 1765; its tolerance stays within a deist frame and does not yet amount to equal civil rights.
Key points
- 01
Calas affair
A concrete judicial error turns abstract argument into public pressure, linking philosophy to petitions, letters and lawyers’ briefs.
- 02
Natural law
No right grounded in nature or humanity authorizes forcing consciences; not doing to others what one would not wish to suffer founds tolerance.
- 03
Prayer to God
The prayer near the end asks that small differences of clothing, language and rite never become pretexts for hatred and persecution.
Explore the ideas in depth
The Calas affair and tolerance
Trace how a judicial error becomes a general argument for tolerance in the Treatise.
Situating the text
Jean Calas, a Protestant merchant, was executed in 1762 after being accused of killing his son to prevent his conversion. Published in 1763 within Voltaire’s campaign, the treatise contributed to the rehabilitation of 1765; its tolerance stays within a deist frame and does not yet amount to equal civil rights. Written on the occasion of the death of Jean Calas, the treatise reconstructs the Toulouse affair, then argues from history, natural law and civic utility that persecuting people for their beliefs is as cruel as it is absurd. Toward its end, a prayer to the God of all beings asks humans to bear with one another.
Following the arguments
Calas affair : A concrete judicial error turns abstract argument into public pressure, linking philosophy to petitions, letters and lawyers’ briefs. Natural law : No right grounded in nature or humanity authorizes forcing consciences; not doing to others what one would not wish to suffer founds tolerance. Prayer to God : The prayer near the end asks that small differences of clothing, language and rite never become pretexts for hatred and persecution.
Continuing the reading
Read the opening account of the Calas case, the chapter asking whether intolerance belongs to natural law, and the prayer to God; then compare the treatise’s limits with later demands for equal rights. Jean Calas, a Protestant merchant, was executed in 1762 after being accused of killing his son to prevent his conversion. Published in 1763 within Voltaire’s campaign, the treatise contributed to the rehabilitation of 1765; its tolerance stays within a deist frame and does not yet amount to equal civil rights.
Questions to carry into your reading
- How does the account of the Calas case prepare the general argument of the treatise?
- Where does Voltaire’s tolerance stop, and whom does it still leave out?
Tolerance becomes an effective demand when it is tied to precise facts, public argument and institutional remedies.
How to read it
Read the opening account of the Calas case, the chapter asking whether intolerance belongs to natural law, and the prayer to God; then compare the treatise’s limits with later demands for equal rights.
Editions & sources
Summaries and key points are original editorial interpretations. They accompany reading the work and do not replace an edition of the text. Editorial method ↗