{First, read all the front matter in your Hackett edition of Hume's An Inquiry concerning Human Understanding as well as Hume's A Letter from a Gentleman to his Friend in Edinburgh, which appears at the end of the book. Inspect the table of contents to get a sense of what's in Hume's Inquiry. Read the editor's introduction (Eric Steinberg is the editor) for background information about Hume's life and work. The letter to his friend in Edinburgh will give you some idea of the religious opposition to Hume (they played hardball in those days) and how Hume answers it, not always ingenuously as you will soon learn. Look over the Hume bibliography to get a feel for the amount and range of his published work. Read the "Advertisement" placed opposite the first page of the Inquiry so that you can see what Hume took to be the relationship of the present Inquiry to his youthful magnum opus entitled A Treatise of Human Nature.}

Section I: Of the Different Species of Philosophy

1.     Hume means by moral philosophy something very different from what this term means today.  What does Hume mean by it?  How is the term used nowadays?

2     Hume distinguishes two types of philosophy which Professor Massey calls soft  philosophy (Hume's easy and humane philosophy) and hard philosophy (Hume's accurate and abstruse philosophy).  How do these two types of philosophy differ from one another?   What are their respective advantages and disadvantages?  (It may help you to sort matters out if you keep in mind that Hume sees himself as practicing accurate and abstruse philosophy, i.e., hard philosophy.)  Which three philosophers does Hume himself name as practitioners of accurate and abstruse philosophy?  Which three does he name as practitioners of easy and humane philosophy?  What does Hume mean in this Section by metaphysics?

3.     Hume is convinced that religion, which he calls superstition, has infiltrated hard philosophy so as to produce pseudo-metaphysical nonsense to cover up and protect its weakness.  What does he think is the sole and universal remedy for debunking the pretensions of pseudo-metaphysics?

4.     What is the new method (pioneered by John Locke) in philosophy that Hume proposes to follow?  Is it appropriate to call it the epistemic turn?  (Did Descartes follow it?)  What negative benefit does Hume hope to achieve by it?  What positive benefits?  Is Hume skeptical about our ability to understand basic facts about the operations of our minds?

5.     What does Hume mean by mental geography?  Why does he attach considerable importance to taxonomy of the mind when he clearly recognizes that taxonomy has very little value in the sciences that deal with physical things?  Does he have any hope that moral science will advance beyond this taxonomic stage?   Is it legitimate to search for a few simple laws to systematize and explain a large mass of taxonomically organized data about the mind?  Does Hume despair of the advent of a Newton of the mind?  What two achievements does Hume hope for from this Inquiry?

                                          Section II: Of the Origin of Ideas

1.     What is a perception of the mind?  What examples does Hume give?  Hume divides the perceptions of the mind into two mutually exclusive and jointly exhaustive classes,  namely, thoughts or  ideas and impressions.  What is the basis for this division?  What examples does Hume give of each class?  How adequate is this division, i.e., is it really mutually exclusive (i.e., no perception belongs to both classes) and jointly exhaustive (i.e., every perception belongs to one or the other of the classes) of the perceptions of the mind?  Is Hume's use of the term impression standard for his day?

2.     What can we think of, i.e., what ideas are we able to have?  Why does our thought appear to be unlimited, i.e., why does there seem to be no limits to what we can form ideas of?  Can we conceive or think things that imply contradictions?  What does Hume take the materials of thought to be?  Where do they come from?  What does Hume take the bounds or limits of thought to be?

3.     For Hume, simple ideas are faint copies of  impressions, whereas complex ideas are ensembles or assemblages of simple ideas.  Is every idea either simple or complex?  By what mental operations does the mind construct or fabricate complex ideas out of simple ones?  What examples does Hume give of simple ideas?  What  examples does he give of complex ideas formed out of simple ideas?  Where do we get the idea of God as an infinitely intelligent, wise and good Being?

4.     Hume advances two important universal theses about ideas.  First, every simple idea is a copy of an impression of inner or outer sense.   Second, every complex idea is a bundle or assemblage of simple ideas, i.e., complex ideas are structured ensembles of simple ideas.  Hume offers two arguments for these theses.  The first argument turns on the observation that, whenever we try to do so, we can always reduce a complex idea to simple ideas that are copies of impressions.  The second argument features people who lack one of the senses (e.g., taste or sight) or who have never been exposed to an object that excites a certain impression, e.g., a congenitally blind person who has never experienced colors or an Eskimo who has never tasted pineapple.  Set out these two arguments in detail.  Which thesis does each support?  How probative are they?  How, according to Hume, can an opponent refute the first thesis?

5.     What is the missing-shade-of-blue thought experiment all about?  Is it a counterexample to the first thesis mentioned in 4. above?  If so, why doesn't Hume discard the thesis, especially since he boasted that it takes only a single counterexample to refute the thesis?  How does Hume resolve the anomaly of the missing shade of blue?  Does he qualify or restrict his general rule that all simple ideas are copies of impressions?

6.     How does Hume propose to use his theory of ideas to cut through obfuscation and pseudo-profound philosophical talk (the method is sometimes called Hume's microscope)?  To discredit a philosophical idea (in Hume’s sense of  idea), is it enough to show that it is not a faint copy of any impression?  Why not?  How does Hume relate the doctrine of innate ideas to his theses that simple ideas are copies of impressions, whereas complex ideas are assemblages of simple ideas?

Section III:  Of the Association of Ideas

1.     Why does Hume think that the flow or stream of our ideas is not random, but is governed by principles or laws of connection or association?  Formulate his principles of the association or connection of ideas, namely: Resemblance, Contiguity in time or place, and Cause or Effect.  Give illustrations of each principle.

2.     Hume thinks everyone will concede that his three principles really do connect or associate ideas one with another.  What he thinks is controversial is his implicit claim that these three principles suffice, i.e., that any other principle of association of ideas is reducible to these three.  How does he think one might establish the completeness of his three principles of association of ideas?  How does he reduce the principle of Contrast or Contrariety to his three principles?  Is it mere coincidence that Newton formulated three laws of motion?

{Like Section II, section IV is one of the most important in the entire book. In a sense, sections II and IV constitute the core of Hume's Inquiry.}

Section IV: Sceptical Doubts concerning the Operations of the Understanding

Part I

1.     Hume claims that all objects of human reason or inquiry (all propositions) fall into one of two classes:  relations of  ideas and matters of fact (this division is called Hume’s Fork).  What examples does he give of  relations of ideas?  In what sciences or disciplines does one usually find them?  Only in mathematics?  Are they discovered or known a priori or a posteriori?  Explain the difference between a priori and a posteriori.

2.     What  examples does Hume give of matters of fact?  Where does one find or meet such propositions? Are matters of fact known a priori or a posteriori?  Are their contraries possible or conceivable?  Are their contradictories possible or conceivable?

3.     What, according to Hume, enables us to get beyond memory and sense perception, i.e., what enables us to know things that are present neither to sense nor to memory?  What examples does he give?

4.     Hume  claims that we never come to know cause-effect relationships a priori but always a posteriori,  i.e., from experience.  What is the thought experiment about Adam supposed to show?  Do  people tend to think they have a priori insight into causal relationships in the case of novel objects or in the case of things dramatically different from those of everyday experience?  What about cases where the causal mechanism is supposed to be highly complicated or to depend on hidden structure?  What about cases where the events are familiar, simple, and without apparent hidden structure, e.g., collisions and motions of ordinary billiard balls?

5.     Spell out Hume's argument for the a posteriori character of causal knowledge, which takes as its premiss the observation that effect and cause are totally different, i.e., that they are distinct events.

6.     Why does Hume limit the role of human reason in causal matters to reduction and systematization,  i.e., to reducing the number and kinds of causes to a few general ones and to explaining the former in terms of the latter?  Why isn't applied mathematics an exception to this claim?

                                                                 Part II
7.     What is the nature of all reasonings concerning matters of fact?  What is the foundation of all our reasonings and conclusions concerning cause-and-effect?   How do these two questions differ from the new one which Hume now raises, namely, what is the foundation of all conclusions from experience?  Formulate Hume's negative answer to this new question, i.e., on what does he say these conclusions do not depend?

8.     What is the utmost that past experience can tell us about which objects follow upon which other objects?  What accounts for our extrapolation to the future and to unobserved objects?

9.     What logical connection or logical relation holds between the following two propositions?
             a.  I have found that such an object has always been attended with such an effect.
             b.  I foresee that other objects similar in appearance will be attended with similar effects.
Is this connection or relation intuitive (analytic)?   Is it demonstrative, i.e., can one deduce the second proposition from the first?  Give Hume's arguments for these conclusions.

10.     According to Hume, all experimental conclusions (conclusions based on experience) are based on or presuppose the principle that the future will be like the past (the so-called Principle of the Uniformity of Nature).  What leads us to expect similar effects from similar causes?  Does a single instance of cause and effect suffice to mold our expectation?  Why not?  What does this fact show?

11.     If the inference in 9. above from proposition a. to proposition b. is neither intuitive nor demonstrative, what kind of inference might it be?  If, in addition, this inference is not experimental (based on  experience), what possibilities remain for it?

12.     How does Hume defuse the objection that all that he has shown is that he can't find a reason or argument that permits him in 9. above to infer proposition b. from proposition a.?  What is the relevance to this of his observation that stupid people and even infants acquire considerable knowledge of cause-and-effect?
 
 

1. Hume thinks that, like religion, many species of philosophy can corrupt morals, reduce enjoyment of life, and make us lazy and presumptuous. How is scepticism (academical philosophy) supposed to avoid these pitfalls? Won't scepticism paralyze us into inaction? E.g., if a person realizes that no reason can be given for inductive inferences (causal inferences), won't he or she hesitate to make such inferences or at least hesitate to act on them?
 

2. Do single cases or single instances of the conjunction of two objects give rise to the idea of cause-and-effect? If not, why does a multiplicity of cases give rise to this idea? What do the foregoing facts show about the role of reason in generating this idea? Could reasoning by itself ever get beyond what is immediately present to the senses or to memory?
 

3. Reason does not prompt us to draw conclusions from experience, i.e., to make inductive or causal inferences, so what principle does prompt such inferences? What is custom? Is it a type of instinct? How does the invocation of custom (habit) remove the difficulty about multiple-case versus single-case causal inferences? Without custom, what would the range of human knowledge be?
 

4. How do we move beyond the hypothetical in our beliefs? If we had no senses and no memory, would all our reasonings be hypothetical? Can we, by reasoning about it, resist custom (habit) when it leads us to infer one thing from another thing that is present to our senses or memory when we have found the two things constantly conjoined in our experience? Is it custom or will, then, that determines what we believe about matters of fact? Was Descartes wrong to think that we have it always within our power to suspend judgment on any proposition that we do not clearly and distinctly perceive to be true?
 
 

5. Belief is only one of many propositional attitudes. Besides believing a proposition, one might merely entertain it or doubt it or imagine it to be true or wish it true or the like. How does belief differ from other propositional attitudes? How, in particular, does belief differ from imagining (i.e., pretending) that a proposition is true (i.e., fiction) or from merely entertaining (i.e., considering) a proposition?
 

6. Hume makes belief in a proposition a matter of a certain feeling or sentiment which accompanies the proposition in our mind. Does Hume offer a definition of this feeling? Why not? Describe the feeling or sentiment of belief? If we were incapable of feeling, would we have beliefs? What would Hume say about the choice of words of someone who expressed his or her belief about the forthcoming presidential election thus: I feel that the Democratic candidate is going to thrash the Republican candidate?
 

7. Hume posits three principles that govern the association of ideas, namely: resemblance, contiguity, and causation. Causation, he has already argued, produces a lively and steady conception of the effect when the cause is present to sense or memory. Do the other two principles of association also do this, i.e., in addition to evoking the idea of the resembled thing or of the contiguous thing, do they also engender a lively and steady conception of this thing? What "experiments" does Hume appeal to in order to substantiate his claim? Do these two principles of association lead to a lively and steady conception of an object when what triggered the idea of the object was another idea without any impression annexed to it? Why can't resemblance and contiguity by themselves ever lead to belief about real existence beyond what is present to sense or memory? What do beliefs prompted by resemblance or contiguity presuppose which not also presupposed by beliefs that are prompted by causation?
 

8. Hume speaks of a sort of pre-established harmony between the course of nature and the course of our ideas. To what harmony or correlation is he referring? Is the principle that effects this correlation reason or custom (habit)? Why is it advantageous to the human organism that it be custom rather than reason that establishes this correspondence? Try to cast your answer to this last question in the form of a Darwinian explanation of the role of inductive instinct (custom or habit) in belief formation.
 
 

{Although this section will not be covered in lecture, recitation, quizzes, or examinations, you should read it and attend to the following points.}
 

First, what is probability? At bottom, Hume is a frequentist when it comes to probability. You'll find Hume saying that probability is the ratio of favorable cases to all cases, where the cases are themselves equiprobable, i.e., probable or comparable in some evident sense. Hume is quite aware that events are often conjoined with some definite frequency other than unity, and that custom leads us to infer one event from the other in the probabilistic case as in the case of constant or invariable conjunction. He seems to think the force of the belief feeling or sentiment is proportional to the probability and that it reaches a maximum in the case of constant conjunction. Second, Hume thinks that it is gratuitous to posit a principle of determinism according to which every event is the effect of a cause that produces its effect invariably.
 
 

Section VII: Of the Idea of Necessary Connection

Part I
 

1. What is the chief advantage of the mathematical sciences over the moral ones? The clarity and univocity of what? What is their chief drawback? The length of what and the complexity of what? Given Hume's theory of ideas as copies of impressions, what is the obvious way or method to eliminate the obscurity and ambiguity of ideas in the moral sciences? What is definition? Why does definition serve to clarify and disambiguate only complex ideas? How, then, does one clarify and disambiguate simple ideas that are obscure or ambiguous? To what is Hume referring when he speaks of a new microscope or species of optics, by which, in the moral sciences, the most minute, and most simple ideas may be so enlarged as to fall readily under our apprehension?
 

2. As a test case of philosophical analysis, Hume applies his new microscope to the idea of necessary connection (power or force or energy). Why did he choose to investigate this particular idea? Why does he think necessary connection is a simple idea rather than a complex idea? (If necessary connection were a complex idea, the way to clarify it or to disambiguate it would be to define it rather than to look for the impression of which it is a faint copy.)
 

3. Does Hume think that the idea of necessary connection is a copy of an impression produced by single instances of physical events that stand in a causal relation? Why not? Does it arise from reflection on the operations of the mind? In particular, does it arise from the control of or influence over the body by the will? What arguments or examples does Hume give to show that we come to know the influence of the will over the body only by experience? Does the idea of necessary connection arise, then, from an impression produced or felt when the mind or will operates on ideas or other mental contents, as when we will to call up ideas or propositions? What arguments and examples does he use to show that we learn the influence of will over thoughts and other mental contents only by experience?
 

4. What is the philosophical thesis known as occasionalism? Was Descartes an occasionalist? What arguments does Hume advance against occasionalism? What, from a Humean point of view, is the

fundamental mistake of the occasionalists? (Hint: Could one hold that necessary connection is a pseudo idea and still be an occasionalist?) Would Hume be convinced or converted if an occasionalist produced a sound argument (valid argument with true premisses) whose conclusion was occasionalism? Why not? What would he take such an argument to show about our methods of argumentation?
 

Part II
 

5. Summarize what Hume takes himself to have shown about the idea of necessary connection at this point. What does he mean when he says that all events seem entirely loose and separate? What seems to be the moral or conclusion of all this? What is the only possible way to avoid this conclusion, i.e., where is the only remaining place one might find an impression that answers to the idea of necessary connection?
 

6. What sentiment or impression does Hume at last find behind the idea of necessary connection when he investigates what happens when we experience a multiplicity of cases wherein an event of one type invariably follows an event of another type? Couldn't a single case of one such event following another such event have given rise to the same feeling or impression? Where is the connection, in the world or in the mind? Isn't necessary connection, then, a case of projecting something mental onto the world? How unusual is this? Do we do it with colors or sounds or tastes? Has Hume now shown that the idea of necessary connection is philosophically legitimate?
 

7. Hume now advances two definitions of cause, namely, (a) an object, followed by another, and where all the objects similar to the first are followed by objects similar to the second, and (b) an object followed by another, and whose appearance always conveys the thought to that other. Are these two definitions equivalent? That is, do they pick out the same events as causes (and as effects)? Is the following restatement by Hume of his definition (a) equivalent to definition (a), namely: an object followed by another where, if the first object had not been, the second never had existed?
 
 

1. Why does Hume think that the problem of liberty and necessity (free will versus determinism) is wholly verbal? How, then, does he propose to solve or settle the dispute?
 

2. What is the doctrine of necessity? Does it fit in nicely with Hume's views about causation? Do human actions come under causal laws? Are there apparent exceptions, i.e., are there any human actions so singular that they seem not to conform to causal laws? How are these apparent exceptions best explained? Could there be any science of human nature without such uniformity?
 

3. Do we find greater uniformity in the natural sphere than in the human sphere? Do some natural events seem not to conform to causal laws? Is physical (natural) causality and necessity different from human causality and necessity? If not, why do most people profess to believe the opposite? Do they really believe what they profess?
 

4. What is liberty in the sphere of voluntary human action? Is it opposed to constraint or to necessity? Is it compatible with human actions being caused, e.g., caused by motives?
 
 

5. Would it refute Hume's views about freedom and necessity (or any other Humean thesis) to show that these views have undesirable moral, political, or religious consequences? Why not? What type of consequences alone serve to refute a thesis?
 

6. Hume claims his views about liberty and necessity are not only consistent with conventional morality but that the latter presupposes the former as a foundation. In what sense does conventional morality presuppose Hume's views about liberty and necessity? Would the practice of praising and blaming as well as the practice of rewarding and punishing make sense if Hume's views were wrong? Are his views really consistent with conventional morality? How does his defense of his claim go?
 

7. Hume's views about causality and human action seem to have two undesirable consequences, namely, that no human actions are morally bad because God, as their cause, is morally responsible for them, and that God is responsible for the evil in the world. How does one get to these two propositions from Hume's views? Is Hume satisfied, apropos the first consequence, by the observation that there is no evil in the whole but only in the parts of the universe? Why not? On what does Hume think judgments of vice and virtue depend? Does he think that God is responsible for evil? What status does he assign to this question or problem? Is inconsistency or contradiction in views about a problem like that of liberty and necessity a serious matter for Hume? Why not? What, then, is the proper province of human reason for Hume?
 
 

1.     On what does Hume think that all reasonings concerning matters of fact are based?  How does imperfect analogy differ from perfect analogy?  Are inferences based on them equally cogent?  What is the observation of the circulation of blood in frogs supposed to show and to be an example of?

2.     How should we assess a theory about the human mind that is needed to explain operations of animal minds?  (In his Treatise, Hume calls this methodological principle his Touchstone for testing theories about minds.) Why does he proceed to apply this touchstone to his theory of experimental reasoning (his theory of how we reason about matters of fact and real existence)?  Does he think that animals, like men, learn many things from experience?  Do they expect that like effects will follow like causes?  Are these inferences or expectations based on past experience?  To what evidence for these claims does
Hume point?  Can one account for these animal inferences or expectations as  instances of reasoning or argument that invokes some sort of  uniformity of nature principle?  Do human children make causal inferences in this way?  Why not?  Is animal belief to be explained in the same way Hume explained human belief?  Why didn't Nature entrust such important operations as causal
inferences to reasoning and argumentation rather than to habit or custom?  Why are some humans better at causal inference than others?  Why are humans better at it than animals are?

3.     Do animals acquire all their knowledge of matters of fact and real existence from sense perception and causal reasoning?  If not, what is it like and where do they get it?  What is INSTINCT?  Is causal reasoning itself an instinct?  Do animals have a priori knowledge of matters of fact and real existence?  If so, how can this be reconciled with Hume's system?  Do humans have a priori knowledge of matters of fact and real existence?  If not, are animals cognitively better endowed than humans?
 
 

1.     How proud is Hume of his argument against miracles?  Are we ever led into error by causal reasoning?  What is the relevance of Hume's example about expecting a week of better weather in June than in December in Scotland?  Do we ever make inferential errors when the conjunction of events on which the reasoning is based has been constant and uniform?  To what do the wise proportion their belief?  How does proof differ from demonstration and from probability?

2.    How common, useful, and necessary is reasoning based on human testimony?  On what does such reasoning depend?  On past experience of human veracity and of the conformity of events to reports about them?  On the relation of cause and effect?  When does the evidence of human testimony have the status of probability?  When does it become proof?  What factors will
enhance the force of testimony?  What factors will diminish it?  Is the improbability of the reported event one of these diminishing factors?  What is the significance of Plutarch's remark "I should not believe such a story were it told me by CATO"?  Did the Indian prince who refused to believe the accounts of snow and ice reason justly?

3.     What does Hume mean by a miracle?  If the reported event is miraculous, is this circumstance direct and full proof against its occurrence?  What if the testimony to the miracle is so solid that its falsity would be miraculous, or even more miraculous than the wondrous event?  What should a rational person conclude if he or she finds a miracle supported by absolutely incontrovertible testimony?
 
 

1.     Has any miraculous event ever been attested to by testimony so solid as to constitute a proof?  Hume gives four reasons why no miracle is ever supported by absolutely incontrovertible testimony?  What are these reasons?  Why are the miracles of one religion proof against those of another?  Has the evidence (testimony) for any miracle ever amounted to a proof?  To a  probability?

2.     What are profane miracles?  What examples does Hume give?  How do they differ from religious miracles?  Might it ever be rational to believe in them?  If so, why can't it ever rational to believe in religious miracles? Why does he reject religious miracles even more strenuously than profane ones?

3.     How does Hume assess the miracles related in the Pentateuch?  How does he purport to reconcile his views about miracles with the Christian religion?  Is his proposed reconciliation successful?  Do you think he's sincere about it?
 
 

1. Hume thinks that the argument from design errs by attributing more to the cause than is found in the effect, i.e., by not properly proportioning the inferred cause to the observed effect. Why is this an error or fallacy? In what way is the argument from design supposed to fall prey to it? When the inferred cause is properly proportioned to the effect, what sort of designer can one infer from the world as the effect or handiwork of this designer?
 

2. Does Hume think it inimical to good morals to deny that the world is produced by a deity who will punish the wicked and reward the good in a future state? Why not? Won't such denial at least corrupt those people who now act only out of fear of divine punishment?
 

3. What is the effect-to-cause-to-effect fallacy that Hume claims to find in those versions of the design argument that infer a providential deity (a supreme being who punishes the wicked and rewards the good) as cause of the world? How does the design argument commit this fallacy? How does Hume respond to the examples of the half-finished building and the solitary footprint in the sand, which purport to show that the effect-to-cause-to-effect form of reasoning is not fallacious? When is this form of reasoning not fallacious?
 

4. Is it possible, given Hume's views about causal inference, to infer that there is a designer behind the universe as its cause? Why not? How does this all square with Hume's endorsement of the design argument in his letter to his friend in Edinburgh? Can you save Hume from self-serving hypocrisy?
 

Section XII: Of the Academical or Sceptical Philosophy
 

1. Why does Hume reject Descartes's method of universal doubt, which he describes as a species of scepticism that is antecedent to science and philosophy? In what way is it antecedent to them (in contrast to mitigated scepticism, also known as academical philosophy, which is consequent upon science and philosophy)?
 

2. What does Hume take the sceptical problem about the external world to be? What kind of a world do people naturally posit? What do they take the connection between their images or ideas and the things in this world to be? How does philosophy destroy this comfortable belief? Would Hume accept Descartes's solution in the Sixth Meditation to the problem of the external world?
 

3. Is the question whether sense ideas are produced by external objects that resemble them a proposition that expresses a relation of ideas or a matter of fact? If the latter, how can the question be answered since only ideas are present to the mind? Can one give a rational answer to this question?
 

4. Hume thinks that the reasons philosophers have had for locating secondary qualities in the mind rather than in the world also apply to primary qualities. Why does he think this? What are the sceptical consequences of this position?
 
 

Part II
 

5. Hume thinks scepticism about mathematics (reasonings about relations of ideas) turns on the paradoxes or antinomies that derive from the alleged infinite divisibility of matter. How does he propose to avoid these problems? Does he agree with Descartes that clear-and-distinct ideas could never contradict one another? What sceptical consequences for knowledge about matters of fact stem from Hume's views about causality?
 

6. Having discovered the limits of reason, we should confine our reasonings within these limits. What are these limits? How, in accordance with these limits, should we decide which books to keep and which to throw away if we are resolved to rid our library of books that contain nothing but sophistry and illusion? Would we throw away Descartes's Meditations? Hume's Inquiry?
 

END OF STUDY GUIDE ON HUME'S INQUIRY