Epistemology: Knowledge, Skepticism, and Ignorance

1. Epistemology: Knowledge, Skepticism, and Ignorance Clark Wolf Director of Bioethics Iowa State University jwcwolf@iastate.edu

3. Argument for Analysis: Everything I believe is consistent with the hypothesis that I am being deceived by a powerful evil demon. But even a powerful evil demon could not convince me that I don’t exist when in fact I do exist. For when I doubt my existence, I immediately realize that there must be something (or someone) doing the doubting. When I doubt whether the statement “I exist” is true, I immediately realize that it cannot be false, for the act of doubting must be done by someone: by an “I” who must exist. Even if I am deceived in everything else, I cannot be deceived– cannot be wrong– about my own existence. “Thus, after everything has been most carefully weighed, it must finally be established that this pronouncement “I am, I exist” is necessarily true every time I utter it or conceive it in my mind.” (p. 493.1)

4. Everything I believe is consistent with the hypothesis that I am being deceived by a powerful evil demon. But even a powerful evil demon could not convince me that I don’t exist when in fact I do exist. For when I doubt my existence, I immediately realize that there must be something (or someone) doing the doubting. When I doubt whether the statement “I exist” is true, I immediately realize that it cannot be false, for the act of doubting must be done by someone: by an “I” who must exist. Even if I am deceived in everything else, I cannot be deceived– cannot be wrong– about my own existence. “Thus, after everything has been most carefully weighed, it must finally be established that this pronouncement “I am, I exist” is necessarily true every time I utter it or conceive it in my mind.” (p. 493.1) 1) When I try to doubt that the statement “I exist” is true, I realize that there must be some subject (me) doing the doubting. 2) If there is a subject doing the doubting, that subject must exist. 3) Whenever I doubt the statement “I exist,” it is immediately evident that I exist. 4) Conclusion: The statement “I exist” is self evidently true.

5. Argument for Analysis: I’m obviously imperfect, full of doubts and false beliefs. But I have an idea of perfection, and this idea is itself perfect. Nothing imperfect could create something perfect, so this perfect idea cannot have come from me, it must have come to me from another source. But only a perfect source could cause a perfect idea. So there must be a perfect being—God– who is the cause of my perfect idea.

6. I’m obviously imperfect, full of doubts and false beliefs. But I have an idea of perfection, and this idea is itself perfect. Nothing imperfect could create something perfect, so this perfect idea cannot have come from me, it must have come to me from another source. But only a perfect source could cause a perfect idea. So there must be a perfect being—God– who is the cause of my perfect idea. 1) I have a perfect idea. 2) Nothing perfect could come from something imperfect. 3) I am imperfect. 4) This perfect idea could not have come from me. (From 1,2,3) 5) Only a perfect being could be the cause of a perfect idea. (A new claim, but interestingly related to premise 4.) 6) There must be a perfect being. (From 1,5) 7) If there is a perfect being, that being would be God. 8) Conclusion: God Exists. (From 6,7)

7. Argument for Analysis • Mind and body are either the same substance, or they are different substances. If two things are identical, then they will have all the same properties. So if my mind and body are the same substance, they must have all properties in common. But I can doubt my body’s existence– my body is dubitable. I can’t doubt my mind’s existence– my mind is indubitable. Therefore mind and body are different substances.

8. Mind and body are either the same substance, or they are different substances. If two things are identical, then they will have all the same properties. So if my mind and body are the same substance, they must have all properties in common. But I can doubt my body’s existence– my body is dubitable. I can’t doubt my mind’s existence– my mind is indubitable. Therefore mind and body are different substances. 1) Mind and body are either the same thing, or they are different substances. 2) If two things are identical, then they will have all the same properties. 3) So if my mind and body are the same substance, they’ll have all properties in common. 4) But I can doubt my body’s existence– my body is dubitable. 5) I can’t doubt my mind’s existence– my mind is indubitable. 6) Mind and body do not have all properties in common. 7) Therefore mind and body are different substances.

9. Argument for Analysis: According to Descartes, we can’t know something unless we are so absolutely certain that it is true that we can’t doubt it. But if we accepted this, we would be forced to conclude that we know nothing at all, or almost nothing. It’s just wrong to say that we don’t know something just because we can doubt that it’s true, or just because it’s possible that it’s false: this isn’t what we mean by the term ‘know.’ For example, when I say “I know where I parked my bike, because I remember doing it.” I don’t mean to indicate that I can’t possibly be wrong about where I parked my bike, even if it turns out that I’m a brain in a vat. So to know something isn’t to be certain about it. So the Cartesian analysis of knowledge doesn’t capture what we typically mean by ‘knowledge.’

10. Argument for Analysis: 1) According to Descartes, we can’t know something unless we are so absolutely certain that it is true that we can’t doubt it. 2) But if we accepted this, we would be forced to conclude that we know nothing at all, or almost nothing. 3) But we know more than the Cartesian view would support. 4) So to know something isn’t to be certain about it. 5) Descartes was wrong to believe that certainty is necessary for knowledge.

12. SKEPTICISM: Sextus Empiricus • Plato distinguished “knowledge” from “opinion,” urging that we know only things we discover through reason. • Aristotle and others call into question Plato’s claim that we know the things Plato thinks we know “through reason.” • So what do we know?

13. SKEPTICISM: Sextus Empiricus • Question: What is knowledge? • CLAIM: You don’t know something unless you have good evidence that it is true. • Question: Do you know that you are in a philosophy classroom in Ames Iowa on a cold March morning?

14. SKEPTICISM: Sextus Empiricus Thought Experiment: • (1) Do you know that the world did not spring into existence four seconds ago. • (2) Do you know that you are not a brain in a vat?

17. An Argument for Skepticism: • 1) You have no evidence that you’re not a “brain in a vat.” • 2) If you have no evidence for X, then you don’t know X. • 3) Therefore, You don’t know you’re not a brain in a vat. • 4) If you don’t know that X is false, but your belief Y would be unsupported if X were true, then you don’t know Y. • 5) Therefore, you don’t know any of the things that depend on the fact that you’re not a brain in a vat. • 6) If you’re a brain in a vat, then everything else you believe is false. • 7) Therefore, you don’t know any of those things. • 8) Therefore you don’t know anything at all.

18. An Argument for Skepticism: • 1) You have no evidence that you’re not a “brain in a vat.” (Is this true? What evidence might you offer?) • 2) If you have no evidence for X, then you don’t know X. • 3) Therefore, You don’t know you’re not a brain in a vat. • 4) If you don’t know that X is false, but your belief Y would be unsupported if X were true, then you don’t know Y. (Is this a questionable premise?) • 5) Therefore, you don’t know any of the things that depend on the fact that you’re not a brain in a vat. • 6) If you’re a brain in a vat, then everything else you believe is false. • 7) Therefore, you don’t know any of those things. • 8) Therefore you don’t know anything at all.

19. Skepticism: • Skepticism: We do not have knowledge of anything at all.

20. Epistemology: Theory of Knowledge • What is ‘knowledge?’ What is it to know something? • What does it mean to say that a belief is ‘justified?’ • What can we know? We might start by listing the things we believe:

21. Knowledge and Belief • We have a vast collection of beliefs, and some of them are false:Some people believe that astrology can inform us about our futures. …mind is constituted by the physical operation of the brain. …mind is soul, an entity separate from brain activity that will survive the death or our bodies. …the universe is ultimately describable in terms of physical laws. …a full description of the universe will include magic and super-natural entities. …aliens from outer space are in contact with human beings. …human beings are the product of natural evolutionary selection. …there is a God who created everything and who cares about us. …human beings will make settlements on Mars. …human beings are more likely, in the next millenium, to deplete the earth of its resources and destroy the ecosystems on which we depend for our lives. • Sifting and sorting: We don’t agree on all of these (at least, it’s unlikely that we do.) Those beliefs about which we're less certain are less likely to count as knowledge than those we're more certain of. Are there any beliefs of which we are absolutely certain?

22. Knowledge and Belief • We believe many things. • Not all of the things we believe are things we know. • Among the things I believe, which are the things I know? • Sextus? • Descartes?

23. Knowledge and Belief • Among the things I believe, which are the things I know? • Hypothesis: The things I know are the beliefs that are true. • Problem: What if I have true beliefs by accident or for bad reasons?

24. Knowledge: Platos’s Analysis • Plato, Euthyphro: Knowledge is Justified True Belief. • A person S knows a proposition P If and only if: 1) S believes P2) S is is justified in believing P3) P is true

25. Knowledge: Platos’s Analysis • A person S knows a proposition P If and only if: 1) S believes P2) S is is justified in believing P3) P is true 1a) What is belief? (Mental attitude associated with accompanying dispositions) 1b) What are the objects of belief? (Propositions: Statements that can be true or false.) 2) When is belief justified? (There are alternative theories of justification)3) What is it for a proposition to be true? (There are alternative theories of truth)

26. Knowledge: Platos’s Analysis JUSTIFICATION AND BELIEF: The 'Why?' game...: at a certain point in a child’s development, she gets the idea that there are reasons for things, and start asking why. Justification: A theory of the justification of beliefs must provide us with a model of how to play the why game, or as it is sometimes called, the justification game.

27. Skeptical Scenareos Sextus Empiricus' Trilemma (Also called Agrippa’s Trilemma, after Agrippa the Skeptic. This is a Modern Rendition): 1) We have knowledge only if our beliefs are justified. 2) 'justification' can take three possible forms: A) We justify our total belief set by reference to some foundational belief or set of such beliefs, which are not themselves justified by any further beliefs. B) Our beliefs mutually justify one another. C) There is an endless regress of justifying reasons. 3) Not A: A foundational belief could not justify other beliefs unless it were itself justified. 4) Not B: Circular justification is no justification at all. 5) Not C: An endless regress of reasons could not provide justification for our first-level beliefs. 6) Therefore, we don't have knowledge.

28. Skeptical Question: • Do we know anything at all? • If I might be dreaming, might be a brain in a vat, might be systematically deceived by an evil genius… …then can I know anything?

29. Many epistemic theories, like that of Descartes, are attempts to show that skepticism is false, and that we can have justified beliefs in spite of the force of skeptical arguments.

30. A Coherent Skepticism? • Skepticism: The view that we don’t have any knowledge. “Nothing can be known, not even this.” -Carneades ~214-129 BCE “The skeptical dictum is like a purgative: when we take it, the dictum itself is thrown up along with all our other dogmatic beliefs.” -Miguel de Montaigne

31. Sextus Empiricus: • Skepticism is an ability to place reasons in opposition to one another, so as to achieve a balance that leaves us free of dogmatic beliefs. • Is skepticism self-contradictory? The skeptic claims we have no knowledge (?), but isn’t making that claim a violation of the skeptical imperative to avoid making positive claims?

32. Sextus, Epicurus, and Epictetus: • All three urge that philosophy can provide us with peace of mind, and protect us from unhappiness. • Ataraxia- (Epicurus and Sextus) Freedom from worry, created by passions or dogmatic convictions. • Apatheia (Epicurus, Seneca) Freedom from passions, and the false beliefs that generate passions. • Acatalepsia (Sextus) The ability to withhold both assent and denial from doctrines that are presented to us for belief.

33. Sextus: • Goal of skepticism is freedom and peace of mind. • Skepticism is an ability to withhold assent, that can be mastered with practice and study. • We exercise this ability by considering all the evidence against a proposition alongside the evidence for it.

34. Sextus Empiricus: Q: Why is skepticism characterized as an “ability?” A: It would be inconsistent for a skeptic to have a “doctrine,” since adherence to a doctrine involves belief and commitment. (Connect this with the common charge that skepticism is inconsistent…)

35. A Coherent Skepticism? • Skepticism: The view that we don’t have any knowledge. “Nothing can be known, not even this.” -Carneades ~214-129 BCE “The skeptical dictum is like a purgative: when we take it, the dictum itself is thrown up along with all our other dogmatic beliefs.” -Miguel de Montaigne

36. Sextus: • Question: In denying that we know anything, is the skeptic denying ‘knowledge’ in the Platonic sense, or merely denying that we have certainty about things? (Fallibilism)

37. Sextus and the Modes: • The modes are methods we can use to achieve the suspension of judgment (aporea or acatalepsia) that allows us a kind of freedom we would not have if we were to submit to dogmatic beliefs.

38. Modes of Skepticism: 1) The same objects don’t produce the same impression in different animals. 2) Differences between individuals lead to differences in perception of the way things are. 3) Different senses give us very different information about the objects we perceive. 4) Differences in our circumstances cause things to appear differently to us. (sleep/wake, drunk/sober)

39. Modes of Skepticism 5) When we perceive objects from different positions, they appear different to us. 6) We perceive objects in groups, and the “admixture” of different objects causes each to be perceived differently by us. 7) When substances are in different states, they appear differently to us. (snow/water) 8) Our perception of objects is relative to ourselves and circumstances. (?)

40. Modes of Skepticism 9) Our perception of objects changes depending on whether we see them frequently or seldom. 10) Ethical judgments appear to be based on custom, and different people with different backgrounds make different judgments.

41. Sextus’s Instruction: • Whenever you are tempted by dogmatism, line up reasons for and against the proposition until they balance out. • At this point, you will be free from convictions (acatalepsia) having lost the propensity to dogmatic adherence. • In this state, you will be free trouble (in a state of ataraxia) since we are only bothered when our dogmatic convictions or judgments are thwarted by the world.

42. Compare Skepticism and Stoicism: • Skeptics and stoics (and Epicureans too) agree that our goal should be to free ourselves from troubles arising from false beliefs. • While the stoics recommend extirpation of desires and aversions, the Skeptics recommend extirpation of dogmatic convictions. • The stoics agree that disturbances (desires and aversions) arise from false beliefs. But they do not recommend eliminating our beliefs.

43. Skeptical Ataraxia? • Abandoning dogmatic convictions will leave us free and happy: we will be undisturbed by things that disturb other people. Their disturbance rests on a mistake: they have allowed themselves to believe where they should instead have withheld belief and judgment.

45. Knowledge and Belief: Descartes’s Problem • Descartes's Problem: How can I have knowledge of anything, and which are the things I know? • Sifting and sorting: Those beliefs about which we're less certain are less likely to count as knowledge than those we're more certain of. Are there any beliefs we're absolutely certain of?

46. Knowledge and Belief: Descartes’s Problem • DF of "undermining:" A proposition P undermines another proposition Q just in case the truth of P would be good evidence either (i) that Q is false, or (ii) that our reasons for believing Q are not good reasons for believing Q. • Proposed Principle for Negative Justification: Take any propositions P and Q where P undermines Q. If you have no evidence that P is false, then you are not fully justified in believing Q. • But: If you have no evidence that the “Demon hypothesis” is false, then you are justified in believing none of the things that would be undermined by this hypothesis.

47. Knowledge and Belief: Descartes’s Problem • Descartes, Meditation I: The Dream Argument 1) In Meditation 1, Descartes believes that he is sitting before a fire.2) But if Descartes is in bed dreaming, then he's not before a fire.3) Descartes argues that he has no evidence (or inadequate evidence) to justify his belief that he's not dreaming. 4) So he doesn't know that he's not dreaming. 5) So he doesn't know that he's sitting before a fire.

48. DESCARTES: Meditations on First Philosophy • Meditation One: Introduces Skeptical Problem, Method of Doubt, distinguishes among different sources of belief. • The Project: Wholesale reconstruction of a belief system: Descartes wants to tear it to the ground and build it back from solid foundations.

49. DESCARTES: Meditations on First Philosophy • THE SKEPTICAL PROBLEM: • The starting point: recognition that many previously held beliefs are either false or unfounded. We need, he believes, a firm foundation on which to place our knowledge, to insure that our beliefs will be true.

50. DESCARTES: Meditations on First Philosophy • Method of Doubt: Test beliefs according to their "doubtability." If I can doubt one belief, but I cannot doubt another, then surely my belief in the second is firmer than my belief in the first. For the moment, Descartes recommends that I admit only those truths (if any) which I can immediately perceive clearly and distinctly. Any others whose truth I can derive from this basic set will also be justified.