- Grace causes the Christian to act, reason the philosopher. Other men are carried away by their passions, their actions not being preceded by reflection: these are the men who walk in darkness. On the other hand, the philosopher, even in his passions, acts only after reflection; he walks in the dark, but by a torch.
- Denis Diderot in the article on Philosophy, Vol. 25, p. 667, in L'Encyclopédie (1751 - 1766).
- Education begins the gentleman, but reading, good company, and reflection must finish him.
- John Locke, as quoted in The Book-Lover's Enchiridion (1884) by Alexander Ireland, p. 94.
- To doubt everything or to believe everything are two equally convenient solutions; both dispense with the necessity of reflection.
- Henri Poincaré in Preface, Dover abridged edition (1952), p. xxii, in Science and Hypothesis (1901).
Hoyt's New Cyclopedia Of Practical Quotations 
- Quotes reported in Hoyt's New Cyclopedia Of Practical Quotations (1922), p. 660.
- The next time you go out to a smoking party, young feller, fill your pipe with that 'ere reflection.
- The solitary side of our nature demands leisure for reflection upon subjects on which the dash and whirl of daily business, so long as its clouds rise thick about us, forbid the intellect to fasten itself.
- James Anthony Froude, Short Studies on Great Subjects, Sea Studies.
- The learn'd reflect on what before they knew.
- Let the Tribune put all this in its pipe and smoke it.
- Richmond, Virginia Enquirer (Feb. 7. 1860).
- For take thy ballaunce if thou be so wise,
And weigh the winde that under heaven doth blow;
Or weigh the light that in the east doth rise;
Or weigh the thought that from man's mind doth flow.
- Edmund Spenser, The Faerie Queene (1589-96), Book V, Canto II, Stanza 43.
- A soul without reflection, like a pile
Without inhabitant, to ruin runs.
- Edward Young, Night Thoughts (1742-1745), Night V, line 596.