Q0446

John Locke

A verified English rendering from the curated archive.

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.
Thinker John Locke
School British Empiricism
Source Essay Concerning Human Understanding, Introduction
Theme Knowledge
Another quotation More from this thinker

Source context

This English passage is associated with Essay Concerning Human Understanding, Introduction, within the tradition of British Empiricism. The wording below is a verified rendering prepared for careful reading rather than a claim of unique translation authority.

A short reading

Read in the register of knowledge, the sentence asks the reader to test an assumption rather than to collect a slogan. In John Locke's wider work, similar claims are usually offered as prompts for judgment: what would have to be true for the sentence to hold, and what would follow if it did?

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.

Same thinker

More from John Locke

  1. Whence has it all the materials of reason and knowledge? To this I answer, in one word, from experience.
  2. 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.
  3. As far as this consciousness can be extended backwards to any past action or thought, so far reaches the identity of that person.
  4. Where there is no law, there is no freedom.
  5. Let us then suppose the mind to be, as we say, white paper, void of all characters.

All quotations by John Locke

Same theme

More on knowledge

  1. What I do not know, I do not claim to know.
  2. No one errs willingly.
  3. What then is time? If no one asks me, I know; if I wish to explain it to one who asks, I do not know.
  4. What do I know?
  5. Once in a lifetime, everything must be doubted.

Browse the knowledge theme