§1 Of the different species of philosophy

1. §1 Of the different species of philosophy • Hume’s goals in this section: • Put up a defense for a certain kind of philosophy: difficult, abstract, painstakingly careful philosophy. • Warn the reader that what follows might sometimes be a little “abstruse” • Reassure the reader that he will avoid unnecessary detail and jargon, and will aspire to clear and smooth prose. • Set up the aim of subverting a certain kind of philosophy: abstruse and jargon-filled metaphysics that serves to protect superstition.

2. §1 Of the different species of philosophy • Two kinds of philosophy: • “easy and obvious” • “accurate and abstruse” [the word ‘accurate’ in Hume’s day means careful, painstaking] • Comparison: • The first kind of philosophy has its advantages. • But you shouldn’t discount the second kind! There is still a real need for it. • Bringing them together: • Hume hopes to “unite the boundaries” of the two kinds of philosophy. • Solid, careful reasoning without extraneous detail, written clearly and artfully.

3. §1 Of the different species of philosophy • “Easy and obvious” philosophy • Takes humans as active. • Tries to influence the reader: make virtue look nice, capture the imagination, stir up the sentiments, etc. • [Here I think of Cicero’s De officiis and Shaftesbury’s Characteristics. Perhaps Hume means to include works that popularize the new sciences.] • Advantages • Has relevance for common life. • Garners more fame and reputation for its practitioners. • Stays within common sense, avoids error. • Avoids extremes, fits the “mixed kind of life” suitable to humans: “Be a philosopher; but amidst all your philosophy, be still a man”

4. §1 Of the different species of philosophy • “Accurate and abstruse” philosophy • Takes humans as reasonable. • Tries to anatomize human psychology, and arrive at basic psychological mechanisms. • Seeks the approval of the scholarly community, and the discovery of hidden truths. • Defense • Accurate psychological anatomy is needed for accurate descriptions of human life and virtue (just as good painters need to know anatomy). • Careful reasoning is useful for all walks of life. • Intellectual curiosity offers “safe and harmless pleasures”; new discoveries open up new intellectual vistas.

5. §1 Of the different species of philosophy • Metaphysics and superstition • Objection: Accurate and abstruse philosophy inevitably leads to “uncertainty and error”. • Reply: This is an important objection. Certain kinds of metaphysics do often provide protection for superstition, which fosters religious and political oppression. • Reply, cont’d: But the only all-purpose cure for this is investigating the limits of the human understanding, and exposing this metaphysics as a pseudo-intellectual fraud. • Defense, cont’d • Mere classification of mental operations (“mental geography”) is itself useful, and only excessive skepticism can find hopeless uncertainty in the project of looking into our own minds and organizing what we find. • And there is real hope that we can even find the basic underlying mechanisms; as Newton did in physics, so we can do in philosophical psychology.

6. So really there are three kinds of philosophy at issue: Easy and obvious philosophy (Hume approves) Careful psychological anatomy (Hume defends) Superstition-protecting metaphysics (Hume attacks) §1 Of the different species of philosophy

7. So really there are three kinds of philosophy at issue: Easy and obvious philosophy (Hume approves) Careful psychological anatomy (Hume defends) Superstition-protecting metaphysics (Hume attacks) “Happy, if we can unite the boundaries of the different species of philosophy, by reconciling profound enquiry with clearness, and truth with novelty! And still more happy, if, reasoning in this easy manner, we can undermine the foundations of an abstruse philosophy, which seems to have hitherto served only as a shelter to superstition, and a cover to absurdity and error!” §1 Of the different species of philosophy

9. §2 Of the origin of ideas • Two main points in this section: • Division into ideas and impressions. • All ideas are copied from impressions. • This is Hume’s statement of empiricism: • Impressions are a matter of experiencing: sensation, emotion, pain, pleasure, etc. • Ideas are a matter of thinking: representing, conceptualizing, imagining, remembering, etc. • All cognitive content comes from experiential content • cf. Locke, who says all the materials of knowledge come from experience

10. §2 Of the origin of ideas • Difference between experiencing and thinking: • Real sense experience is clearly different from imagined or remembered experiences (it has more “force and vivacity”) • Real emotional experience is clearly different from mere thoughts of, conceptions of, or reflections on emotions (one involves “real disorders and agitations” and the other seems “faint and dull”) • Dividing up the mind: • Use ‘perception’ to stand for any mental item. • ‘Ideas’ are the perceptions with less force and vivacity. • ‘Impressions’ are the perceptions with more force and vivacity. • The division is one of phenomenal feel (“vivacity”, “lively”) and perhaps causal power (“force”).

11. §2 Of the origin of ideas • The bounds of thought • The imagination seems boundless; it seems like we can think about anything we like, anything except what’s self-contradictory. • But in fact, we are limited by “the materials [of] the senses and experience”; we are simply performing operations on a limited stock of experiential content. • The ‘copy principle’ • “[A]ll the materials of thinking are derived either from our outward or inward sentiment” • “[A]ll our ideas or more feeble perceptions are copies of our impressions or more lively ones”

12. §2 Of the origin of ideas • Two arguments for the copy principle: • All ideas can be broken down into simple ideas that were copied from impressions. • Even the idea of God (cf. Locke) • Anyone lacking a kind of experience always ends up lacking the corresponding ideas. • Examples: the blind, the deaf, the isolated, the meek, the selfish • One exception: the ‘missing shade of blue’ • We could probably “raise up” an idea of this color via the imagination, despite having never experienced it. • But this exception is not worth worrying about.

13. §2 Of the origin of ideas • A test for meaningless jargon • Suppose you suspect that a philosophical term is meaningless (i.e., has no connected idea). • Ideas are faint, difficult to distinguish, easy to mistake; but impressions are strong, clear, and difficult to mistake. • So just ask: “from what impression is that supposed idea derived?” (or “what experience(s) can that idea be traced back to?”) • And if the term has no connected idea that can be traced back to impressions, then the term is indeed meaningless.

14. §2 Of the origin of ideas • Footnote: what about innate ideas? • Hume hopes anti-nativists like Locke meant nothing more than the copy principle. • If ‘innate’ means natural, then everything in the mind is innate: after all, there’s nothing uncommon, artificial, or miraculous in the mind. • If ‘innate’ means there at birth, then the dispute over innateness is frivolous and uninteresting. • And when ‘idea’ is used to cover everything in the mind, then who could ever deny that ‘ideas’ like self-interest, resentment, and the libido are innate? • Probably Locke was dragged into this dispute by Scholastics, dragged into making a big deal of it and wasting a lot of time on it.

16. §3 Of the association of ideas • Principles of association • The way one idea leads to another is not random, but regular. • Trains of thought, daydreams, dreams, conversations: all involve a chain of connected ideas. • The compound words of different languages often match each other. • [Example: English deduction and its Czech synonym vývod both break down into the literal meaning ‘drawing out of’; transfer and přenéstare both ‘carrying across’] • The three principles • Resemblance: e.g., see a picture, think of what it depicts • Contiguity: e.g., mention one apartment, think of its neighbors • Causation: e.g., think of a wound, think of the pain it causes • Perhaps there are other general principles of association, but Hume hasn’t been able to find any.

18. §§4-5: Reasoning aboutmatters of fact • Our non-rational psychology • Hume’s going to argue that much of our reasoning is driven not by reason, but by habit. • This holds for all reasoning about unobserved matters of fact, all reasoning about cause and effect, and all reasoning from experience. • It works by way of natural instinct, explained in terms of the principles of association and related psychological mechanisms. • The problem of induction • Philosophers have taken away from Hume’s discussion a now-classic epistemic problem. • Can we justify our confidence that the past is a reliable guide to the future? Or is all scientific reasoning based on an unproven assumption?

19. §4 Sceptical doubts concerning the operations of the understanding • “Hume’s Fork” • Relations of ideas: • e.g., a2 + b2 = c2, 3 × 5 = ½ × 30 • intuition and demonstration (cf. Locke) • don’t depend on anything in the real world • the opposite entails a contradiction and is inconceivable (e.g., 2 + 2 ≠ 4 is self-contradictory and inconceivable) • Matters of fact: • e.g., ‘the sun will rise tomorrow’ • both it and its opposite are conceivable, neither one entails a contradiction • Unobserved matters of fact • How do we go beyond present sense experience and memory? • How do we arrive at conclusions concerning unobserved matters of fact? (e.g., distant countries, ancient history) • Hume says it all boils down to reasoning about cause and effect.

20. One billiard ball is about to knock into another: what will happen? A priori reasoning Here’s your situation: No experience: suppose you’ve never observed billiard balls in action, or anything like billiard balls Just sensible qualities: all you have to go on are the observable characteristics of the situation Given this situation, your reason cannot decide what will happen: Any guess will be completely arbitrary: examine the cause all day long, and you won’t find any hint of what the effect will be. There are lots of conceivable ways things might go (the second ball might go up in the air, or start smoking and then explode, or turn into a frog or a bee). Since all of these are consistent, reason cannot privilege any one of them over the others. Billiard balls

21. One billiard ball is about to knock into another: what will happen? A posteriori reasoning Now here’s your situation: Consistent experience: you’ve observed lots of cases just like this one, and events like this have always gone with a certain kind of effect Your reason still cannot decide what will happen: How could reason go from “C and E have always gone together in all previous cases” to “C and E will go together in this case”? What mental process is driving these ‘past-to-future transitions’? It’s not demonstrative reasoning: for there is no contradiction in this case turning out completely different from all previous cases (it’s perfectly consistent that nature will suddenly change course). Nor is it matter-of-fact reasoning: for this kind of reasoning relies on past-to-future transitions, and so it can’t be driving those transitions—otherwise, you get a vicious circularity. Billiard balls

22. One billiard ball is about to knock into another: what will happen? Reason in general A priori reasoning cannot decide what will happen You can’t figure out what will happen unless you’ve seen nature in action: you need some experience to draw on. A posteriori reasoning cannot decide what will happen. Even with experience to draw on, reason cannot make the transition from the previous cases to the current case. For, first, there’s no demonstrative connection between the previous cases and the current case. And second, matter-of-fact reasoning can’t be what explains the transition, given that it relies on that very transition. Reason cannot decide what will happen. In general, our reasonings concerning matter of fact are not based on intellectual processes (i.e., “operations of the understanding”). Billiard balls

23. §4 Sceptical doubts… the understandingThe line of argument • The main argument • Reasonings concerning (unobserved) matters of fact are founded on causal reasoning (4.1) • Causal reasoning is founded on experience (4.1) • Reasoning from experience is founded on a transition from similar previous cases to the current case (4.2) • But that transition is not driven by any process of reasoning (4.2) • The ‘lots of cases’ argument • We draw conclusions only after seeing lots of cases. But if all the cases are alike, then why would reason need to see lots of them? Why wouldn’t a single case be enough? • The ‘idiots, children, and animals’ argument • Even they are capable of learning from experience; but surely they manage to do this without any sophisticated process of reasoning. [cf. Leibniz on “simple Empirics”]

25. §5 Sceptical solution of these doubts • Harmlessness of skepticism • Skepticism, unlike other kinds of philosophy, doesn’t flatter our intellects or encourage our bad habits—maybe that’s why it’s so unpopular! • Even if skeptical philosophy undermines our common sense views, we’ll continue to accept them, because it’s our nature to do so. • Even if the transition from past to future isn’t driven by reason, it’s driven by some other natural psychological mechanism, which will still get the job done. • Why we go from past to future • We don’t have access to the secret powers connecting cause with effect, so without experience we can’t go beyond present sense and memory. • Even once we have experience to go on, we still have nothing but patterns of conjunction—experience doesn’t give us access to the secret powers. • Nevertheless, once we have experience to go on, we confidently form beliefs about what will happen in new cases—but why?

26. §5 Sceptical solution of these doubts • Habit • Reasoning from experience is driven not by reasoning, but by habit. • If two things go together again and again, this frequent repetition leads us to expect that they will continue to go together. • So far, this is just classifying the past-to-future transition under a familiar kind of explanation—Hume hasn’t given us a detailed psychological account of the mechanisms of habit. • This is the only explanation of why we need to see lots of cases before we draw any conclusions. • How it works, in brief • We start with a fact present to the senses or memory. • We draw on experience of previous cases where facts like this one have gone together with other stuff. • Habit leads us (as a matter of natural instinct) to expect that this other stuff will also be there in this case.

27. §5 Sceptical solution of these doubtsPart 2: More detail The nature of belief • What’s the difference between believing an idea and merely conceiving an idea? • It’s not anything in the idea • Otherwise we could voluntarily believe in anything we liked just by tinkering with the idea. • And the very same idea can be both believed and disbelieved. • So it’s the way the mind conceives the idea: a “feeling or sentiment” • A believed idea is more “vivid, lively, forcible, firm, steady” or something like that. • Hence it has more effect on our behavior.

28. §5 Sceptical solution of these doubtsPart 2: More detail Associative boosting • Remember the principles of association • Ideas naturally lead to certain related ideas. • Resemblance, contiguity, causation • Transferring force and vivacity • Suppose that something is present to the senses or memory, and hence very strong and lively to the mind. • And suppose that some principle of association leads you to think of a related thing. • Your conception of the related thing will also end up being very strong and lively. • This works for all three principles of association.

29. §5 Sceptical solution of these doubtsPart 2: More detail • Resemblance • See a picture of a friend, and your idea of the friend will be strong and lively. • Visible religious icons make your religious ideas strong and lively, with more influence on your behavior. • Contiguity • Being near one’s home, as opposed to being far away from one’s home, makes your ideas of friends and family more strong and lively. • Causation • Relics of saints and holy men enliven religious devotion. • Seeing the son of a long-absent friend calls up strong and lively thoughts of the friend.

30. §5 Sceptical solution of these doubtsPart 2: More detail • Reasoning from experience • Suppose x is present to the senses or memory, and x has been repeatedly conjoined with y in lots of previous cases. • This naturally (by association) leads you to think of y. • And it also takes the liveliness of your idea of x and transfers it to your idea of y. • Indeed, it makes this idea so strongly conceived as to become a belief—you will expect y to be there in the present case. • Recap: how habit produces beliefs • Any objects habitually conjoined in one’s experience will enter into the associative principle of causation. • Principles of association will transfer the liveliness of one idea to any related ideas. • Believed ideas are distinguished from merely conceived ideas by their greater liveliness, firmness, steadiness, etc. • Reasoning from experience always starts with something present to the senses or memory.

32. §6 Of probability • Probable reasoning supports Hume’s account • Even though chance isn’t real, and even though there are always hidden explanations for unexpected results, still we have to reason on the basis of incomplete information. • Hume’s theory of belief and his account of causal reasoning can make sense of probable reasoning. • ‘Chance’ • e.g., throwing a die • The mind considers each possible outcome; if one outcome is far more frequent, then (somehow) we end up believing it. • This can be nicely explained if belief is just forcefully conceiving something. • Consistent evidence, mixed evidence • When the pattern of evidence is consistent (a proof), we have full belief. When it’s mixed (mere probability), we give different degrees of confidence to different possibilities. • Again, Hume’s theory of belief and of how we reason from experience explains this.

34. §7 Of the idea of necessary connexion • Where do we get our idea of causal force? • “power, force, energy, or necessary connexion” • Try to trace the idea back to its original impression. • It’s not experienced as out there in the world. • It’s not experienced in our mind’s power over our bodies, or in our mind’s power over our thoughts. • Nor do we experience God’s power over the world. • From experiencing the workings of habit • After seeing two things go together again and again, if we see one of them, habit leads our minds to believe that the other one is also there. • The idea of causal force is taken from the felt experience of our own minds making this move.

36. §9 Of the reason of animals • Explanatory unity • If Hume’s theory of causal reasoning also applies to animals, then it is more likely to be true of humans. • Animals do causal reasoning • They learn from experience. • They can be trained. • But this isn’t driven by reasoning • It would have to be very sophisticated reasoning. • We usually call psychological forces that are insensitive to environment instincts. • But the capacity for causal reasoning is itself an instinct.

38. §10 Of miracles • You can’t establish a religion on human test-imony of miracles. • He has an argument similar to one used by John Tillotson (moderate Archbishop of Canterbury, 1691-1694) against transubstantiation. • He’s writing in a context where Protestants are already skeptical of miracle reports coming from Roman Catholics in continental Europe. • The argument is supposed to convince his Protestant audience that they should be skeptical of any miracle reports in religious contexts.

39. Experience, evidence, and belief • When it comes to matters of fact, experience is our only guide. • And it is a fallible guide. • So we have to proportion our belief to the evidence. • Sometimes we have a perfectly consistent pattern of evidence (a proof), and sometimes we have a mixed pattern of evidence (mere probability). • With proofs, we should have (something like) complete confidence. With probabilities, we should have less confidence.

40. Testimony • Testimony is one source of evidence. • It works the same way: our confidence in certain testimony should be tailored to how often testimony of this kind faithfully represents the facts. • If our experience has shown a certain kind of testimony to be perfectly reliable, then we should be completely confident in it. • And if our experience has shown a certain kind of testimony to be less reliable, then we should be less confident in it.

41. Two factors thatshould lower our confidence • Sometimes our confidence should be lowered because of the nature of the testimony. • Witnesses contradict each other • Only a few witnesses • Doubtful character • They have an interest in what they claim • They hesitate, or they “protest too much” • Other times our confidence should be lowered because of the nature of the event attested to.

42. Nature of the event • Inasmuch as the event attested to “partakes of the extraordinary and marvellous”, we should lower our confidence. • If someone tells you that President Bush gave a State of the Union address wearing a Speedo, you should be highly skeptical. • Why? Because the event itself seems highly unlikely. • Even if the testimony looks pretty credible, the extreme improbability of the event ought to lower our confidence. • Even if you were told this by a proven and trustworthy friend, you should still be skeptical.

43. Miracles • Miracles, by definition, are highly unlikely events – even more unlikely than Bush in a Speedo! • A miracle is a violation of the laws of nature by supernatural agency. • The laws of nature are the most consistent patterns of natural phenomena available to us. • So a miracle is an event whose credibility is threatened by the strongest amount of evidence possible. • “there is here a direct and full proof, from the nature of the fact, against the existence of any miracle”

44. Belief in miracles • So, for belief in a miracle to be reasonable, the testimony in its favor must be so reliable and so credible that it outweighs the intrinsic improbability of the alleged miraculous event. • Hume writes that “no testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous, than the fact, which it endeavours to establish” • The event itself is so incredible, we need extremely credible testimony. • Slogan of the skeptic’s movement: “Extraordinary claims require extraordinary evidence”

45. How strong is the evidence? • Hume says that “there never was a miraculous event founded on so full an evidence”. • He thinks that the quality of the evidence (i.e., the credibility of the testimony) is never strong enough to outweigh the intrinsic improbability of miracles. • But why does he think this? • He raises four points.

46. Point 1 – The testimony itself • We need extremely credible testimony: • lots of witnesses • with good sense, education, and learning • with integrity • with a reputation to lose • attesting in public, where any deception will be found out • But, Hume says, you’ll never find this, not anywhere in history.

47. Point 2 – Human nature • Humans are naturally drawn to tall tales and urban legends and old wives' tales and ghost stories and the like. • We enjoy hearing about them and we enjoy spreading them around. • Religious enthusiasm especially leads us to deceive ourselves and renounce our judgment, and sometimes even to lie to others. • You can see these passions operating in the history of forgeries and frauds.

48. Point 3 – Ignorance • These stories are found in the ignorant distant past, or in ignorant cultures of today. • Ancient histories are filled with wild stories, but as you advance from ancient histories up to modern histories, the wild stories show up less and less. • And even today, we can ask ourselves: who tends to be abducted by aliens? who tends to believe urban legends? who tends to spread ghost stories?

49. Point 4 – Conflicting religions • Each religion has its own testimony of miracles. • If the testimony of this miracle established this religion, then the testimony of that miracle would establish that religion. • And then we’d end up with all religions being true, which is impossible – after all, different religions contradict each other.

50. Hume’s argument • For testimony of a miracle to establish a religion, the testimony would have to be so credible as to outweigh the intrinsic improbability of the miracle. • But testimony of miracles is never that credible (remember Hume’s four points). • Therefore, “no human testimony can have such force as to prove a miracle, and make it a just foundation for any such system of religion”