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Review: An Essay concerning Human Understanding — Locke's theory of mind

2026-07-14 | The Locke Bookshelf Editorial Room

★★★★★4.5 / 5.0 (editorial rating)

Verdict: Locke's other magnum opus, and the founding text of British empiricism. There are no innate ideas, he argues; the mind begins as "white paper," and all our knowledge is built from experience and reflection. Long and demanding — which is why we keep it for last — but once the politics has shown you how Locke thinks, this is the deepest room in the house. Woolhouse's Penguin edition is a well-judged reading text.

An Essay concerning Human Understanding, Penguin Classics (jacket-style image made by this site)
Title
An Essay concerning Human Understanding
Author / Editor
John Locke; edited with an introduction by Roger Woolhouse
Publisher
Penguin Books (Penguin Classics)
Length
~800 pp.
Difficulty
Advanced ★★★ — four to six weeks

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What it is — in three lines

First published in 1689, the Essay is Locke's account of what the human mind can know and how. It opens by attacking the doctrine of innate ideas and argues instead that the mind is at birth "white paper, void of all characters," furnished only later by experience — sensation and reflection. This Penguin Classics edition, edited by Roger Woolhouse, gives you a well-judged reading text of a very long work, with an introduction that orients a first-time reader.

The core — no innate ideas, the mind as white paper

Locke's programme is to map the origin, extent, and limits of human knowledge. All our materials, he argues, come from experience: simple ideas enter through the senses and through the mind's reflection on its own operations, and the understanding then combines them into the complex ideas we think with. From this he develops famous distinctions — primary and secondary qualities, the workmanship of the understanding, the puzzle of personal identity — and a sober conclusion about how much is genuinely within our reach.

Let us then suppose the mind to be, as we say, white paper, void of all characters, without any ideas. How comes it to be furnished? … To this I answer, in one word, from experience.

— Locke, Essay, II.i.2

This is the book that set the agenda for British empiricism and, through Berkeley and Hume, for a century of philosophy after it.

Three highlights

1. The foundation of empiricism

Almost every later debate about perception, knowledge, and the mind starts here. Reading the Essay is reading the source, not a commentary on it.

2. The famous set-pieces

Primary and secondary qualities, the "molyneux problem," and the memory-based account of personal identity are landmarks of philosophy — and they are vivid and argued, not dry.

3. Woolhouse's reading edition

The Essay is enormous; Woolhouse's Penguin text and introduction make a sane starting point for a first encounter without demanding the full scholarly apparatus at once.

What to watch out for

Two honest notes. First, it is long and uneven: at some 800 pages, Locke repeats himself and digresses, and few first readers go straight through every chapter. Use the introduction to pick a path — Books II and IV are the heart. Second, read it after the politics, not before: coming to the Essay once Dunn and the Two Treatises have shown you how Locke argues makes the theory of mind far less forbidding. This is the deep end, kept for last on purpose.

Editorial room notes Reading time: four to six weeks for the whole, less if you follow the introduction's path through Books II and IV. Our rating rests on first-hand reading and bibliographic checking; the score reflects the monumental importance of the work alongside the real demands of its length. Quotation cited to book/chapter/section. A Kindle edition is available. Several other reputable editions (Oxford, Hackett) exist; this Penguin text is a strong reading choice.

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