Ethics & justice
What we owe each other — duty, fairness, and how to reason about right and wrong.
Ethics is applied clear thinking about the hardest subject. Kant’s categorical imperative tests a rule by whether it could be universal; Rawls’s veil of ignorance designs a just society from behind it; Plato’s cave frames the philosopher’s duty to return with the truth. These are the tools for reasoning about how we should treat one another.
Key ideas here: The Categorical Imperative, The Allegory of the Cave, The veil of ignorance, Immanuel Kant, Plato — and 6 more below.
Mental models
The veil of ignorance
The veil of ignorance is a thought experiment for fairness: design the rules of a society — or any deal — as if you didn’t know which position in it…
Via negativa
Via negativa is the principle that improvement often comes from removing the harmful, false, or unnecessary rather than adding something new. Knowing…
Cognitive biases
Just-world hypothesis
The just-world hypothesis is the tendency to believe the world is fundamentally fair — that people get what they deserve and deserve what they get. It…
Omission bias
The omission bias is the tendency to judge harmful actions as worse than equally harmful inactions. We feel more responsible for damage we cause by…
Ideas
The Categorical Imperative
Kant's supreme moral rule: act only on a principle you could will everyone to follow, and treat people as ends, never merely as means.
The Allegory of the Cave
Plato's image of prisoners mistaking shadows on a wall for reality — a picture of how education turns the soul from illusion toward truth.
Eternal Recurrence
Nietzsche's thought-experiment: if you had to live your life over and over, identically, forever — could you affirm it?
Thinkers
Schools
Related topics
Go deeper
The book behind this idea: The Republic by Plato. Hear the whole thing free — start an Audible trial and your first audiobook is on the house.
Read the full summary of The Republic →
More canonical picks:
- Thinking, Fast and Slow — Daniel Kahneman
- The Art of Thinking Clearly — Rolf Dobelli
- The Great Mental Models, Volume 1 — Shane Parrish
- Poor Charlie’s Almanack — Charlie Munger
- Super Thinking — Gabriel Weinberg & Lauren McCann
- Seeking Wisdom — Peter Bevelin
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Editorial synthesis © ReadGlobe. Each idea links to a full reference page with sources.