Study Guide for John Locke,
Essay on Human Understanding

in Modern Philosophy:
An Anthology of Primary Sources

(Hackett Publishing Company, 1998), pp. 270-373

Contact: Dr. Jan Garrett

Last modification (only a minor one) February 9, 2004

The Essay is divided into four books (i-iv), chapters (indicated by upper-case Roman numerals in this study guide), and sections (indicated by Arabic numerals without 'p' or 'pp.')

Some key passages for understanding of Locke. Read these first.

Editors' introduction to Locke's Essay and Associated Texts, pp. 259-260 II I.24-Locke's foundationalist approach to theory of knowledge.

Book I

Chapter I

1. What method does Locke say he is following? (I.3)

2. Why is it useful to know the extent of our comprehension? (I.4)

Chapter II

3. What arguments in favor of the doctrine of innate ideas does Locke discuss? (See sections 2, 6, 17).

4. How does Locke refute the argument that certain universally accepted principles exist, and that that proves they are innate? (Sections 3-5)

5. How does Locke refute the claim that innate ideas are those that are known by men when they come to the age of reason? (Sections 7 ff.)

6. How does Locke refute the claim that general ideas are proven innate because men assent to the corresponding propositions as soon as they are proposed. (Sections 18ff.)

Book ii

Chapter I

1. Is it Locke's purpose to develop a theory of how movements in our sense organs produce ideas in our minds? (VIII.4, p. 285.2; XXI.73, p. 309) What properties in sensible objects cause our ideas, in Locke's view?

2. What is the mind like originally? (I.2)

3. What are the two major sources of our knowledge? (I.2-6)

4. Is the power of perception an active or a passive power? The power of reflection? (XXI.72, pp. 308-309)

5. At what time of life do we begin getting ideas of sensation? Ideas of the operations of one's own mind? (I.7-8)

Chapter II-VI

6. What are simple ideas? Give examples. What function do they play in Locke's theory? (II.1-2)

7. Are there simple ideas conveyed by more than one sense? (V) If so, what?

8. Name some simple ideas of reflection. (VI)

Chapter VII-VIII

9. Are their simple ideas of both sensation and reflection? (VII) If so, what?

10. What objects suggest ideas of existence and unity? (VII.7)

11. How does Locke understand (define?) idea? (VIII.8)

12. What does Locke call qualities? (VIII.8) Give some examples of qualities?

13. Distinguish primary qualities from secondary qualities. Give examples of each kind. (VIII.9-10)

14. What tertiary qualities does Locke mention? (VIII.10, 24) Why are they distinguished from secondary qualities?

Chapter XI-XII

15. How does Locke understand abstraction? (XI.9)

16. Are any ideas actively constructed? (XII.1) What are these called? Under what three heads does Locke classify them? (3)

17. What does he mean by "mode"? Give examples of modes. (XII.4-5)

Chapter XXI

Chapter XXI is a lengthy dissertation (over 50 pp. in the unabridged version) on the problem of free will and determinism, or in Locke's vocabulary, liberty and necessity.

On this issue, people divide into compatibilists and incompatibilists, depending on whether they think free will (or responsible agency) is compatible with determinism.

Compatibilists are generally soft determinists, which, in spite of the name, does not mean that they relax determinism, which would amount to adopting indeterminism, but that they believe both that determinism is true and that there exists free will (or responsible agency). The ancient Stoics, J. S.Mill, and, according to many scholars, Aristotle are classed as soft determinists.

The incompatibilists divide into two camps, depending on which side of the incompatibility they affirm.

Those who affirm determinism and deny liberty or free will are called hard determinists. Among them appear to be seventeenth century philosopher Spinoza, French Enlightenment thinker D'Holbach, Friedrich Nietzsche, the famous American lawyer Clarence Darrow, and behavioral psychologist B. F. Skinner.

Those who affirm freedom and reject determinism are sometimes called (metaphysical) libertarians. They include thinkers as different as ancient atomist philosopher Epicurus, Immanuel Kant, existentialist Jean-Paul Sartre, and American process philosopher Charles Hartshorne.

  Liberty/Free Will ExistsThere is no free will
Determinism is true Compatibilism/ Reconciliationism:
Soft Determinism

(Stoics, J. S. Mill, etc.)

Hard Determinism

(Spinoza, D'Holbach,
Nietzsche, Darrow,

Indeterminism is true Metaphysical libertarianism

(Epicurus, Kant,
Sartre, Hartshorne)


18. Try to decide, as you read this section, with which of these groups, if any, Locke can be classified.

19. Give an example of passive power and active power. From what do we receive the idea of passive power? (XXI.4) Do bodies give us a clear idea of active power?

20. Where do we find the original of our idea of active power? (XXI.4-5)

21. What does Locke mean by "liberty"? (XXI.8)

22. Why does Locke think that the question whether the human will is free is an unintelligible question? (XXI.14)

23. Is a man at liberty to will or not to will? (XXI.24)

24. Can we ask what moves desire? (41) How does Locke understand happiness? (42) How does Locke understand the good? (42) (How does his view stack up against Aristotle's? Against the Stoic view?)

25. In what lies "the liberty man has"? (XXI.47)

Chapter XXII

26. What examples of mixed modes does L. give in XXII.1 (p. 310)?

27. What sort of ideas are these mixed modes? (1) Are they marks of real beings with steady existence? Do they sometimes correspond to something real? (2)

28. How do we get the idea of murder if we have never seen one committed? (3)

29. From what does an idea of a mixed mode get its unity? (4)

30. What are three ways by which we get complex ideas of mixed modes? (XXII.9)

Chapter XXIII

31. Why do we suppose the existence of substance? (XXIII.1)

32. When we examine our notion of pure substance in general, what do we find, according to Locke? (2) In what do qualities like color inhere? In what do those qualities in turn inhere? (2)

33. Do we have a clearer notion of mental substance, or soul, than we do of material substance or body, in Locke's view? (XXIII.5)

34. Does Locke reject the existence of material and mental substances? (George Berkeley, who writes after Locke, will deny material substance and David Hume, who writes after Berkeley, will deny both.)

35. Do we have complex ideas of substances? Explain. (XXIII.6)

36. Most of the qualities of which we are aware in substances are of what sort? (8-10)

Book iii

1. Does Locke believe in the existence of things other than particulars, for example, general natures or universals, such as Platonic forms or Aristotelian species? How do words become general? (III.6, p.410)

2. How are general ideas formed? (III.7)

3. How are even more general ideas formed, e.g., Animal as more general than Man? (III.8-9)

4. Of what are general or universal terms the invention and creature? (III.11)

5. What does Locke mean by "real essence"? (III.15)

6. What does Locke mean by "nominal essence"? (III.15) Which kind of essence is virtually identical to the abstract idea for which a general name stands?

7. When, according to Locke, are nominal and real essences the same? Different? (III.18) Explain the latter in terms of the nominal and real essences of gold.

8. Does Locke think it is possible to know the real essence of mental or spiritual substances? Of God? (VI.11) How do we get--and what are--our ideas of spirit and God?

9. Upon what do the higher genera (more abstract groupings) of substances which are constructed depend to a great extent? (VI.32)

Book iv

Chapters I-IV

1. How does Locke define knowledge? (I.2)

2. What three acceptations (senses) of "knowledge" does Locke distinguish? (I.8-9) Don't confuse these with the three degrees of knowledge to which he comes shortly.

3. What does he mean by intuitive knowledge? (II.1) Demonstrative knowledge? (II.2ff.) How do each of these kinds of knowledge stand in relation to doubt? (II.5)

4. Sensitive knowledge? (II.14, p. 344)

5. Relate in order of increasing extension--what we have ideas of, what we know, what is real. (Which includes, but is greater than, which?) (III.1-6) How far does sensitive knowledge reach? (III.5)

6. What view about morality does L. try to support with his discussion of the ideas of property and injustice III.18, p.350?

7. Why is mathematical reasoning less problematic than ethical? (III.19)

8. With respect to what things do we have knowledge of their real existence? What kind of knowledge? (III.21)

Chapter X-XI

9. How, in his view, do we know the existence of God? (X) The argument is given in X.2-6.

10. How does Locke justify his claim that our senses give us knowledge of things outside the mind? (XI)

Chapter XV-XVI

11. How does he understand probability? (XV.3-4) Would Locke find meaningful the mathematician's notion that some things have a probability of 100%?

12. What grounds of inducement for assent does he note? (XV.4)

13. Locke distinguishes the highest degree of probability (assurance) from the next highest degree (confidence). (XVI.6-7) To what do each of these pertain? (See his examples.)

14. Regarding what sorts of things may we make some right judgments if we reason by analogy? (XVI.12)

15. What does Locke say about faith (XVI.14, p. 373.2) How is rational assent related to revelation? (373.2)