Theme

Reason philosophy quotes

Reason is the capacity to give and assess reasons—central to logic, science, ethics, and public argument.

Why this theme matters

Philosophers disagree about whether reason is the slave of the passions, the legislator of morality, or one tool among others. The quotations here keep that disagreement in play.

In the history of philosophy

From Aristotelian logic and Confucian rectification of names to Enlightenment rationalism and twentieth-century critiques of instrumental reason, the theme spans method and ethics.

Thinkers in this collection

Plato , Lucretius , Anselm of Canterbury , William of Ockham , René Descartes , Blaise Pascal , Immanuel Kant , Thomas Aquinas

Frequently asked questions

What is reason in philosophy?

It is the capacity to infer, explain, justify, and revise beliefs and actions according to norms of good thinking.

Do all philosophers trust reason equally?

No. Some exalt it; others warn that reason can rationalize desire, ideology, or domination unless checked by experience and virtue.

Where should I start with philosophy quotes about reason?

Begin with short passages that distinguish reasoning from mere persuasion, then follow the thinker pages for fuller context.

  1. Let us not become haters of argument — that is a great danger to the soul.
  2. Nothing can be created from nothing by divine agency.
  3. Therefore death is nothing to us, and does not concern us at all.
  4. Faith seeking understanding.
  5. Plurality should not be posited without necessity.
  6. I think, therefore I am.
  7. The things we conceive very clearly and very distinctly are all true.
  8. The heart has its reasons, which reason does not know.
  9. Dare to know! Have the courage to use your own understanding!
  10. Grace does not destroy nature, but perfects it.
  11. Reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them.
  12. Do not block the way of inquiry.
  13. Accept the truth from whatever source it comes.
  14. It is of the nature of reason to perceive things under a certain form of eternity.
  15. The state of nature has a law of nature to govern it…Reason…teaches all mankind…that being all equal and independent, no one ought to harm another in his life, health, liberty, or possessions.
  16. Reason is wholly inactive, and can never be the source of so active a principle as conscience, or a sense of morals.
  17. Enlightenment is the human being's emergence from his self-incurred immaturity.
  18. What is rational is actual; and what is actual is rational.
  19. Prudence is right reason applied to action.
  20. Good sense is the best distributed thing in the world.
  21. Reason is, and ought only to be the slave of the passions.
  22. Truth does not contradict truth; rather it agrees with it and bears witness to it.
  23. Entities must not be multiplied beyond necessity.
  24. Nothing is without a reason.
  25. Not to laugh at, lament, or detest human actions, but to understand them.