Q0446
“It is of great use to the sailor to know the length…” — John Locke (Essay Concerning Human Understanding, Introduction)
Verified English quotation. Primary source: Essay Concerning Human Understanding, Introduction. Theme: knowledge.
English
It is of great use to the sailor to know the length of his line, though he cannot with it fathom all the depths of the ocean.
Source and attribution
The archive attributes this English wording to Essay Concerning Human Understanding, Introduction and files it under British Empiricism. That locator distinguishes the passage from loose internet attributions: readers can return to the named work or section to check translation, surrounding argument, and edition-specific wording.
About John Locke
John Locke (1632–1704) was the English philosopher of empiricism and liberal politics whose Essay Concerning Human Understanding and Two Treatises of Government defined a century’s agenda. Associated with Shaftesbury and the Glorious Revolution settlement, he wrote on toleration, education, and money.
How to read this passage
Epistemology asks whether knowledge is justified true belief, reliable tracking of the world, or something else; it also asks how perception, testimony, memory, and reason contribute. This passage enters that discussion through knowledge, humility, method.
Concepts in this quote
- Knowledge
- Knowledge is the philosophical study of what we can justifiably claim to know—and where certainty ends.
- Humility
- Humility appears in this archive as a live philosophical concern—not a slogan. These verified English passages show how thinkers treat humility as a problem of judgment, practice, or explanation.
- Method
- Method appears in this archive as a live philosophical concern—not a slogan. These verified English passages show how thinkers treat method as a problem of judgment, practice, or explanation.
How to cite this quotation
APA: John Locke. (n.d.). It is of great use to the sailor to know the length of his line, though he cannot with it fathom all the depths of the ocean. In Philosophy Blind Box. https://www.philosophydef.com/quotes/q0446
MLA: John Locke. “It is of great use to the sailor….” Philosophy Blind Box, https://www.philosophydef.com/quotes/q0446.
Chicago: John Locke. “It is of great use to the sailor….” Philosophy Blind Box. Accessed 2026. https://www.philosophydef.com/quotes/q0446.
Frequently asked questions
What is the source of the quotation “It is of great use to the sailor…”?
The passage is attributed to John Locke, Essay Concerning Human Understanding, Introduction. The archive attributes this English wording to Essay Concerning Human Understanding, Introduction and files it under British Empiricism. That locator distinguishes the passage from loose internet attributions: readers can return to the named work or section to check translation, surrounding argument, and edition-specific wording.
What does John Locke mean by knowledge?
Epistemology asks whether knowledge is justified true belief, reliable tracking of the world, or something else; it also asks how perception, testimony, memory, and reason contribute. This passage enters that discussion through knowledge, humility, method.