What is Justification?

Transcription

1 What is Justification?

2 Propositional knowledge many of the most intriguing questions about knowledge turn out to be questions about propositional knowledge. It will be the focus of this book. (p. 12)

3 What are propositions? An American tourist is trekking through jungle with a local guide, who speaks little English. Tourist: Guide: Tourist: Are there snakes around here? Snakes? What is snakes? I can t believe it! He grew up in the jungle and doesn t know what a snake is!

4 TAK (JTB theory) S knows that p = df (i) S believes that p (ii) p is true (iii) S is justified in believing p. These 3 conditions are individually necessary and jointly sufficient.

5 Belief To believe p is to take p to be true. Belief is a matter of degree (subjective probability) Only good beliefs, those with nothing wrong with them, count as knowledge.

6 Truth Feldman endorses a correspondence theory of truth (as most analytic philosophers do). On this view, in addition to the many and conflicting human viewpoints about reality, there is also a single viewpoint-like entity called the facts, or the actual world. [Colourfully called the God s eye view, or the view from nowhere. ] The actual world is a proposition, or is similar to a proposition, in that it stands in logical relations like consistency and consequence with propositions. The actual world is an ultimate (i.e. indefeasible) authority for human belief.

7 Correspondence to objective facts Objective facts seem to be very much like propositions, except that they are somehow objective, or in the world rather than in the head.

8 Truth be the actual world. Proposition p is true p. Proposition p is false p N.B. All possible worlds are maximal. determines the truth value of every proposition.

9 One alternative: anti-realism there is nothing to be said about either truth or rationality apart from descriptions of the familiar procedures of justification which a given society ours uses in one or another area of inquiry. we should think of true as a word which applies to those beliefs upon which we are able to agree, as roughly synonymous with justified. (Richard Rorty, Science and Solidarity)

10 [Kuhn] has said that there is no theory-independent way to reconstruct phrases like really there. He has asked whether it really helps to imagine that there is some one, full, objective, true account of nature and that the proper measure of scientific achievement is the extent to which it brings us closer to the ultimate goal. (Rorty) Objects do not exist independently of conceptual schemes. We cut up the world into objects when we introduce one or another scheme of description. (Hilary Putnam, Reason, Truth and History, 1981, p. 52).

11 Are students anti-realists? There is one thing a professor can be absolutely certain of: almost every student entering the university believes, or says he believes, that truth is relative. If this belief is put to the test, one can count on the students reaction: they will be uncomprehending. That anyone should regard the proposition as not self-evident astonishes them, as though he were calling into question = 4. Allan Bloom, The Closing of the American Mind, 1987, p

12 Kant s idealism Kant didn t deny, of course, that there are such things as horses, houses, planets and stars; nor did he deny that these things are material objects. Instead his characteristic claim is that their existence and fundamental structure have been conferred upon them by the conceptual activity of persons. According to Kant, the whole phenomenal world receives its fundamental structure from the constituting activities of mind. Were there no persons engaging in noetic activities, there would be nothing in space and time, nothing displaying object property structure, nothing that was true or false. (Alvin Plantinga, How to be an anti-realist, Proceedings and Addresses of the American Philosophical Association, Vol. 56, No. 1. (Sep., 1982), pp

13 Thomas Aquinas and divine intellect "Even if there were no human intellects, there could be truths because of their relation to the divine intellect. But if, per impossible, there were no intellects at all, but things continued to exist, then there would be no such reality as truth." (De Veritate Q. 1, A.6 Respondeo). The actual world is the God s eye view? 13

14 True belief isn t enough A pessimist believes that it will rain during the picnic, and it does. (But the pessimist always predicts rain, and is wrong most of the time.) You get a curious feeling that your brother (who rarely calls) will call later that day. And he does! Did you know that he would call? To fill the gap between true belief and knowledge, apparently something else is needed. Justification

15 What is justification? Feldman takes an evidentialist view of justification. A belief is justified if one has good enough reasons to hold the belief, strong evidence for it, etc. Justification requires strong evidence, but not conclusive evidence. E.g. W. K. Clifford s negligent ship owner lacks evidence. N.B. Acting on a belief is sometimes rational, even when the belief is rather weak (low probability). (See decision theory)

16 Epistemic vs. moral/pragmatic justification A major league baseball player is coming to bat in a crucial situation. This player is a good hitter: He gets a hit about one-third of the times he comes to bat. Still, more often than not, he fails to get a hit. Like many other major league players, he is supremely confident: Each time he comes to bat he believes that he will get a hit. This sort of confidence, we may assume, is helpful. Players do better when they are confident (believe that they will succeed), and they do worse when they lack confidence.

17 Total evidence condition A person can have strong evidence for p, and see clearly how that evidence supports p, and yet not be justified in believing p. How is that possible? The person has even better evidence that p is false! A justified belief must be probable (at least) on the person s total evidence.

18 Epistemic duties Laurence Bonjour (The Structure of Empirical Knowledge, p. 8) one s cognitive endeavors are justified only if and to the extent that they are aimed at this goal [truth], which means very roughly that one accepts all and only those beliefs which one has good reason to think are true. To accept a belief in the absence of such a reason... is to neglect the pursuit of truth; such acceptance is, one might say, epistemically irresponsible. My contention here is that the idea of avoiding such irresponsibility, of being epistemically responsible in one s believings, is the core of the notion of epistemic justification.

19 Epistemic duties Feldman argues against the idea that justification requires gathering all the evidence that s easily available. (The case where a prof takes his wife to see Star Wars.) Do you agree?

20 Epistemic duties Is epistemically responsible to trust and accept beliefs that form spontaneously within one s own mind? What about strange hunches? What about pessimistic (or optimistic) beliefs? What about (apparent) clairvoyant experiences? What about (apparent) sense perceptions, memories, logical intuitions, etc.? If we do have epistemic duties to check, verify, gather more evidence, etc. then how far do they extend?

21 Assurance: What if we feel very certain? But when I turn my thought onto the things themselves the ones I think I perceive clearly I find them so convincing that I spontaneously exclaim: Let him do his best to deceive me! He will never bring it about that I am nothing while I think I am something; or make it true in the future that I have never existed, given that I do now exist; or bring it about that two plus three make more or less than five, or anything else like this in which I see a plain contradiction. (Descartes) Locke also refers to the assurance we have from our senses themselves that they don t err in what they tell us about the existence of things outside us when we are affected by them and says: As for myself, I think God has given me assurance enough of the existence of things outside me (Essay, Book IV, Ch. Xi part 3)

22 The best assurance I can have, the best my faculties are capable of, is the testimony of my eyes; they are the proper and sole judges of this thing. I have reason to rely on their testimony as being so certain that I can no more doubt that while I write this I see white and black and something really exists that causes that sensation in me, than I can doubt that I write or that I move my hand. This is a certainty as great as human nature is capable of concerning the existence of anything except oneself and God (Locke, Essay, Book IV, Ch. Xi part 2)

23 In a similar vein, Thomas Reid criticises Descartes approach to sensory knowledge, namely giving a rational proof that the senses are reliable. (Thomas Reid, IHM 6.20, , publ. 1764)

24 The sceptic asks me, Why do you believe the existence of the external object which you perceive? This belief, sir, is none of my manufacture; it came from the mint of Nature; it bears her image and superscription; and, if it is not right, the fault is not mine: I even took it upon trust, and without suspicion. Reason, says the sceptic, is the only judge of truth, and you ought to throw off every opinion and every belief that is not grounded on reason. Why, sir, should I believe the faculty of reason more than that of perception? they came both out of the same shop, and were made by the same artist; and if he puts one piece of false ware into my hands, what should hinder him from putting another?

25 Control freak or laissez faire? Some managers are control freaks, or micro-managers. They don t trust their workers to do anything properly, and so check up on everything. Other managers are hands off, or laissez faire. They trust their workers, to the extent of not really knowing what s going on. The conscious part of the mind can manage to some extent, its own belief formation. What duties do we have to oversee (and in some cases overrule) these processes? When is it legitimate to relax and trust our cognitive mechanisms (e.g. perception) to do their job?

26 Epistemic duties Is epistemically responsible to trust and accept beliefs that form spontaneously within one s own mind? What about strange hunches? What about pessimistic (or optimistic) beliefs? What about (apparent) clairvoyant experiences? What about (apparent) sense perceptions, memories, logical intuitions, etc.? If we do have epistemic duties to check, verify, gather more evidence, etc. then how far do they extend?

27 Duties require internal access? Suppose you take on a new job at the nuclear power plant and I instruct you to press a certain button if the temperature of the reactor core goes above a certain point. You see a dial which is labeled Reactor Core Temperature. You ask me, So what you mean is, I should press this button whenever the indicator on that dial goes above that line? Now suppose I respond, No, that's not what I mean. That dial might not be working properly. I want you to press the button whenever the reactor core is above the danger point, regardless of what that dial says. (Jim Prior, on his web site) Can you do that?

28 Internal access needed for justification? A person has a justified belief only if the person has reflective access to evidence that the belief is true.... Such examples make it reasonable to conclude that there is epistemic justification for a belief only where the person has cognitive access to evidence that supports the truth of the belief. Justifying evidence must be internally available. [My emphasis] Earl Conee (Monist, July, 1988 p. 398)

29 Internalism in epistemology refers to 3 related claims: i. Access internalism: knowledge requires actual or ii. possible access to one s evidence for the belief. Duty ( deontological ) internalism: knowledge requires that the belief is formed in an epistemically responsible way. iii. Mentalist internalism: what ultimately justifies any belief is some mental state of the epistemic agent holding that belief.

30 Various kinds of access internalism Actual Access KI: One knows some proposition p only if one is also aware of one s knowledge basis for p. Accessibility KI: One knows some proposition p only if one can become aware by reflection of one's knowledge basis for p.

31 Mentalism Bob and Ray are sitting in an air-conditioned hotel lobby reading yesterday's newspaper. Each has read that it will be very warm today and, on that basis, each believes that it is very warm today. Then Bob goes outside and feels the heat. They both continue to believe that it is very warm today. But at this point Bob s belief is better justified. Comment: Bob s justification for the belief was enhanced by his experience of feeling the heat, and thus undergoing a mental change which so to speak internalized the actual temperature. Ray had just the forecast to rely on. (Conee and Feldman 2001, p. 236)

32 Brain in a vat case The normal woman s sensory beliefs are justified (I guess?) What about the other woman s beliefs?

33 Clairvoyance case Suppose that Bob and Carol have clairvoyant experiences that are internally indistinguishable. Carol is (unknown to her) a true clairvoyant. Bob is mentally ill, and hallucinating. Let s say they both trust their spontaneous clairvoyant beliefs, since they feel the assurance that Locke spoke of. Are Carol s spontaneous clairvoyant beliefs justified? Are Bob s?

34 Duty vs. Authority The notion of justification is based on the idea of doing your duty. This notion of duty can be contrasted to that of being authorised. Note that the notions of duty and authority are both normative. Doing your duty (being responsible, etc.) is a good thing. But acting under proper authority is also a good thing of a rather different kind.

35 Duty vs. Authority E.g. imagine that police detective A is working for an inspector who seems honest and straight. His reputation is excellent. There s no evidence of corruption. The inspector provides detective A with what looks like a search warrant for some property, and the detective searches the property. Did detective A do his duty? Did A act responsibly? (Surely he did.)

36 As a matter of fact, however, A s inspector is crooked, and the warrant is a forgery. Was detective A s search of the property authorised (by a judge)? (Clearly not.)

37 In another city, detective B has an inspector who has a bad reputation. Everyone suspects he s corrupt. B asks his inspector for a warrant to search a suspect s property, and one is provided in a surprisingly short time. B thinks the warrant is probably fake, but searches the property anyway. Did detective B do his duty? (Arguably, he had a duty to investigate further, in which case he failed to do his duty.)

38 As a matter of fact, B s inspector is honest, and the warrant is genuine, signed by the judge. Was detective B s search of the property authorised? (Clearly, yes.)

39 Authority is an external matter A s search was justified, but unauthorised. B s search was unjustified, but authorised. N.B. Authority is something that the detectives have no cognitive access to. It concerns external states of affairs, outside the mind.

40 Externalism Externalists think that the gap between knowledge and true belief can only be filled by something external, i.e. something that we have no cognitive access to. Some such suggested external states of affairs are: 1. The belief that p is caused by the fact that p. 2. The belief is formed by a reliable cognitive process. 3. The cognitive process that formed the belief was working properly.

41 What about animal knowledge? Externalists regard Emma (an intelligent dog) as knowing things, even though she has no reason to think that her spontaneous beliefs are true. Surely, it is argued, Emma was justified in believing and, perhaps even more clearly, knew such things as that there was a squirrel on the other side of the quad (as she skulked carefully toward it, freezing if it should happen to look in her direction) or that the person at the front door was her good friend Marc (as her initial hostile barking at the person s approach gave way to yelping and jumping with excitement and joy). (BonJour, p. 207)

42 ... it is doubtful whether Emma could have even understood the basic idea of having a reason for a belief, an understanding that seems to be required for her to have had fully explicit access to any reasons at all. Thus it is hard to avoid the conclusion that Emma had no justified beliefs

43 It seems clear that Emma s beliefs are not justified, in the sense of being epistemically responsible. What epistemic duties could dogs have? Some externalists conclude from this that justification isn t a matter of doing your epistemic duty, but is something else, something external. Other externalists (e.g. Alvin Plantinga) want to leave the traditional meaning of justified unchanged, as being epistemically responsible. Plantinga defines the term warrant as whatever turns a true belief into knowledge. Warrant may include justification, but also depends on external factors.