Lecture Notes on Hume's Enquiry

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This web page is provided only for my students for purpose of review. It is not for direct citation in any scholarly papers. (I have not had the time to carefully distinguish quoted material from my own close paraphrase.)

Epistemology From Descartes to Hume

1. Locke:

a) rejects the notion of innate ideas;

b) we have no idea unless it derives from what was first in the senses or from reflexion upon the active powers of the mind.

c) we do have abstract (general) ideas, which we form by abstracting common attributes from particular ideas of sense.

d) ideas are simple or complex--the complex arising sometimes from combination of simple ideas--we have no simple idea that did not arise originally from sense-perception.

2. Berkeley:

a) accepts Locke's rejection of innate ideas

b) rejects the notion of abstract ideas--all ideas are concrete, but there are general words which help us group particular ideas in virtue of similarities.

c) matter would be an abstract idea

d) notions, however, are allowed, such as the notion we have of ourselves and God as mental substances.

David Hume

The numbers (1-26) correspond to the Study Questions on Hume
provided on this web site.

1. Hume divides our perceptions into two classes, impressions on the one hand, and ideas or thoughts, on the other. Impressions he describes as all our more lively perceptions, while ideas or thoughts are less forceful and less lively perceptions. Hume claims that "the most lively thought is still inferior to the dullest sensation." Impressions are also distinguished from ideas inasmuch as the former are perceptions as they first appear in the mind; the latter are copies of the former. (497)

2. According to Hume, the creative power of the mind amounts essentially to this: the faculty of compounding, transposing, augmenting or diminishing the materials afforded us by the senses and experience. (497)

Note: Hume does NOT include the power of abstraction. In fact, elsewhere he rejects the notion of abstract ideas altogether. (On this point he agrees with Berkeley and disagrees with Locke.)

3. What two arguments does H. give in support of this conclusion?

(a) introspect: analyze your experience; produce that idea which is not derived from the senses; you cannot.

(b) whoever lacks the organ for a given type of sensation, lacks the correspondent ideas (497-98)

4. The way to ascertain the meaning of a philosophical term, according to Hume, is to ask from what impression the meaning (or idea) behind a term can be derived. If no such impression can be identified, then term itself may well be meaningless. (498)

5. Hume identifies three principles of association (according to which our ideas are associated)? (i) resemblance; (ii) continguity; and (iii) cause or effect (499)

6. He divides "the objects of reason or inquiry" into two groups: (i) relations of ideas, or necessary truths, which may be discovered a priori (without special consultation of experience); (ii) matters of fact, or contingent truths, which may be discovered a posteriori (by consulting experience).

For Hume relations of ideas are illustrated by the truth 1+1=2 and the truth that the shortest distance between two points is a straight line; matters of fact include that the sun rose today, that it will rise tomorrow, and, if it is a truth, that all crows are black (499-500)

7. Hume notes that all reasonings concerning matters of fact seem founded on cause and effect connections. He justifies this claim with the observation that by means of this relation alone can we go beyond the (immediate) evidence of memory and senses (500).

For example, we are reading a book which states on the cover that it is by David Hume; we have never seen Mr. Hume, but we might infer his existence as part of the cause to which this book is the effect. Cause-effect relationships are the connections by awareness of which we avoid solipsism.

8. Knowledge of cause-effect relations is attainable entirely a posteriori, from experience (501) No laws of nature can be known a priori.

By way of elaboration, Hume says that "the effect is totally different from the cause and can never be discovered in it"--billiards example (501)

9. Like Locke Hume holds that natural science ("natural philosophy") will not let us discover the ultimate causes of things. The ultimate principles or causes of things are wholly hidden from human curiosity. It is Hume's view that we only directly experience the surface of things (502)

Those devotees of science who look to it to unlock the ultimate secrets of natures are sadly mistaken. (Hume seems to be quite out of sympathy with the fundamental project of natural science a.k.a. natural philosophy.)

10. How would H. reply to those rationalists who would say that physical knowledge is mathematical and hence a priori?

Mathematics assists us in the formulation and application of natural laws but it does not give us the laws; they must be discovered a posteriori.

For example "s=1/2 g t²" is used to calculate the distance (s) a free falling body will fall towards the earth in a given number of seconds (t); 'g' is the acceleration constant reflecting the earth's gravitational pull; that g=32 ft/sec. sec. had to be discovered; it could not be derived a priori from the idea of distance, acceleration and time.

11. It cannot be demonstrated (i.e., by deductive reasoning a priori) that because (1) all X's have in the past been followed by Y's, (2) X's in the future will be followed by Y's.

There is no necessary connection between (1) and (2).
(2) does not logically follow from (1).
(1) might be true and yet (2) could be false. (503)

12. To argue in a probabilistic manner that the future will be like the past is circular. (504)

Consider:

[In the past] regularities which have been observed before t were observed after t

So probably _________________________________

[In the future] regularties which we have observed will be observed.

Probabilistic arguments rest upon the assumption that the future will generally be like the past. But when we ask for a proof of this, we are supposing that this assumption should not be taken for granted. Therefore, to presuppose it here is to beg the question, to assume what needs to be proved.

13. From the answers to 11 and 12, we can infer the following about the epistemological status of the principle "similar events have similar effects":

We cannot know the principle either a priori (by discovery of relations between ideas) or a posteriori (by deduction from an empirical premise).

14. Yet there is a "principle" (which here seems to mean cause) that determines us to infer the existence of one object from another.

This is custom or habit--the propensity produced by the repetition of any act or operation to renew the same act or operation without being impelled by any reasoning or process of the understanding (507)

Without the influence of this habit, we would be entirely ignorant of every matter of fact beyond what is immediately present to the senses and memory (508)

15. The basis for our justified beliefs in historical matters of fact is this: some fact(s) present to senses or to sense-memory. For example, I read something in a book and then make a series of causal inferences, typically, from effect to cause, which in turn is an effect of a prior cause, etc.--all the way back to eye-witnesses and spectators of the original (508).

Present datum e ----> c [author of book]
e -------> c [evidence in archive]
e -----> c [writing of the evidence]
e ------> c [eye-witness]

Section V, Part II

16. Hume distinguishes between what we regard as fiction and what we believe in as follows: To belief, but not to fiction, is attached some sentiment or feeling, which must be excited by nature and does not depend upon the will or the preference of the believer. (509.1)

Hume describes the sentiment associated with belief as follows: a more vivid, lively, forceful, firm, steady conception of the object than what the imagination alone is able to attain. Belief and fiction are not distinguished by the content of the ideas but in the manner of their conception. (509-510)

17. According to Hume, belief in the existence of things not present to sensation arises from present objects and customary or habitual connexions. The mind naturally moves from the object (taken as effect or cause) to its absent counterpart (cause or effect) (512)

18. Hume clearly wants to deflate claims that some philosophers have made for the power of reason. He argues that it is not probable that causal inferences could not be trusted to "the fallacious deductions of our reason

He points out that we expect causal connections very early in life, long before we engage in explicit reasoning. As soon as an infant anticipates one thing from the presence of another, e.g., a hug from the presence of its mama, it is using an ability to discover causes from effects or vice-versa. (512.2)

19. Note that H. appears to use the terms moral and metaphysical interchangeably in Section VII.

Hume says that the "chief obstacle" to improvement in the moral or metaphysical sciences is "the obscurity of the ideas and the ambiguity of the terms."

Hume proceeds to focus on some of those terms ideas and terms: the ideas of power, force, energy or necessary connection (514)

20. Complex ideas, he says, are known by definition, i.e., by enumeration of the simpler ideas that compose them simple ideas. What we should do in this case is to "produce the impressions or original sentiments (feelings) from which the ideas are copied."

This is what we might "Hume's microscope". The impressions, he claims, are all "strong and sensible." He seems to think that they admit of no deception, or at least minimum deception. They "throw light on" the correspondent ideas. The key to removing lack of clarity is the study of impressions corresponding to our ideas. Hume adopts the metaphor of the microscope which, by helping us to enlarge the image of what is seen, is an aid to greater clarity and comprehension. (515)

21. When we consider the operation of causes in the external world, we are never able to discover any power or necessary connection . . . which binds the effect to the cause and renders the effect an inevitable result of the cause (515.2)

Nor are we able to discover it when we consider the internal operations of the mind.

Hume considers the alleged causal relation from the mind (decisions) to the body (motion of bodily part)

He gives three arguments to support his view (516.1-517.1)

1. The mind's relation to the body remains mysterious if we suppose the mind to be spiritual or mental (i.e., immaterial) substance and the body to be gross (heavy) matter. (This is not Hume's own view, but it is one we encounter in many others, such as Descartes and Malebranche.)

2. Mind cannot move just any part of the body--it can move the hand, but not control the heart; and we cannot know this distinction except by experience, and we cannot explain why causality works in the one case but not in the other.

3. When I raise my arm, what begins the motion of the arm are motions in the nerves, muscles and currents in the nerves about which most of us are ignorant when we will to move the arm, and yet decisions operate reliably to produce physical movement. This is inherently puzzling, and just further confirms the mysteriousness, to our understanding, of the causal relationship operating here.

22. Hume points out that we cannot discover a clear impression corresponding to the idea of power associated with our apparent ability to entertain and dismiss ideas.

Rather, we just experience the constant conjunction of willing a certain idea into the center of our attention and its appearance there.

Moreover, the power of the mind over itself is limited--for instance, we have more control over our ideas than over our feelings ("sentiments and passions"), and we learn what these limits are only a posteriori, through experience.

Finally, self-command is different at different times, but we learn how to anticipate a strong or weak operation of self command only from experience.

All these cases are evidence that the connexion between mental causes and their mental effects is not itself an idea to which would correspond an internal perception worthy of being called an impression. (517)

Perhaps To Be Continued