Primary sourceBook
Summa Theologiae: Part 2b, On Vices
Thomas Aquinas
A section of Aquinas's Summa Theologiae dealing with sin and vice, part of his major theological work.
This is part of Aquinas's own major theological work, showing his systematic treatment of sin and vice.
About this source
What it is
This is part of the Summa Theologiae, the major theological work written by Thomas Aquinas. This section, part of the Treatise on Habits, deals with vice and sin: their causes, kinds, and effects, including questions on original sin and the difference between venial and mortal sin.
Why it matters
The Summa Theologiae was Aquinas's attempt to organise Christian theology into a clear, logical system, often by posing questions and working through arguments. This section on vice shows his careful method of breaking a huge moral topic into smaller questions, which became a model for later Catholic ethical thinking.
Look closer
- Why might Aquinas organise his work into numbered questions rather than flowing chapters?
- What does the detailed breakdown of sin and its causes tell you about how seriously medieval thinkers took moral philosophy?
- What questions does Aquinas ask that still matter to people today?
This book is part of the curated material that grounds the AI version of Saint Thomas Aquinas on Humy.ai — when students ask about related events, the AI can quote it and cite it.
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