Читать книгу This Is Epistemology - J. Adam Carter - Страница 16

^1.1 Imagine that a team of scientists develops a device that can scan your brain and record everything you believe. You put on the special helmet, the device scans your brain, and the scientists print it all out so you can take home Your Book of Beliefs. Thumbing through the pages, you come across many beliefs you expected to find in Your Book of Beliefs. You also discover some beliefs you didn't expect to find in there – for example, beliefs that play a role in guiding your behavior but which are for the first time being brought to your attention for critical inspection.¹ For better or worse, none of your beliefs has escaped detection by this remarkable helmet (not even the embarrassing ones).

^1.2 Your Book of Beliefs is, in one sense at least, very useful. You find out, once and for all, everything you believe – which is very helpful to know! But you realize something important is missing. You notice there is nothing anywhere in Your Book of Beliefs that tells you which of your beliefs are actually worth keeping and which ought to be abandoned.

^1.3 If you've read a bit of psychology, you probably know that certain kinds of beliefs can be helpful to have simply because thinking about them makes you feel better about yourself, allows you to cope effectively with stressful experiences, etc. Such beliefs might be good to have simply because having them helps us get by.

^1.4 While it might be nice to know which beliefs can help you to get by or find peace, the very fact that you're reading an epistemology book suggests you might not care only about whether your beliefs are useful to you in this way. If you have an inquiring mind, you might also be interested in having beliefs that actually match up with how things are, regardless of whether having them makes you feel happy or comfortable or helps you cope.

^1.5 Let's assume you're like this, and so you want to work out which of your beliefs are worth keeping and which ought to be abandoned from the specific point of view (the epistemic point of view of interest in epistemology) where what matters is things like getting to the truth and having knowledge. That is, you want to sort your epistemically justified beliefs from your epistemically unjustified beliefs – and not to have them have them unhelpfully lumped all together (as they presently are in the book the scientists have given you).

^1.6 So you begin creating a new book: Your Book of (Epistemically) Justified Beliefs.² Unfortunately, the scientists who created the helmet are simply not willing or able to help you fill out this second book. (They say that, as scientists, they are “in the business of describing, not evaluating”.) When they scan your brain, the helmet is simply unable to detect things anything that philosophers call normative – like good and bad, right and wrong, justified and unjustified.³ It simply includes in the book whatever beliefs you in fact do have, for better or worse. If you want to know which beliefs from Your Book of Beliefs belong in Your Book of Justified Beliefs (where being “justified” is a normative matter), you need to do some epistemology, which is the area of philosophy that studies this kind of thing. Epistemology, if done well, can help you figure out not only which (if any) beliefs you have are epistemically justified, but also which ones are known, and even how much knowledge you have.

^1.7 But where to start? Here it helps to take things slowly. In order to figure out which beliefs from Your Book of Beliefs should make it in to Your Book of Justified Beliefs, you'll obviously need to apply some kind of sorting method.⁴

^1.8 Fortunately, you already have a decent grip – before doing much or any epistemology – of which beliefs of yours seem already like the best candidates for justified beliefs (and which ones don't). Looking through Your Book of Beliefs, you notice the first two entries as:

B1 (Belief 1). Rental prices will continue to increase in London in the coming year.

B2. There are ghosts.

You are fairly confident that B1 is justified and that B2 is not, and this is helpful because if whatever sorting method or rule you apply doesn't get these rather easy cases right, it's – like flipping a coin – probably not a very good way to sort the justified from the unjustified beliefs.⁵

^1.9 At any rate, it seems like something must account for why B1 and B2 differ in their being justified.⁶ In a bit more detail, B1 must have some feature that B2 lacks, and this feature must surely account for the difference in justification.

^1.10 This basic idea – that any difference in justification must be explained by some other difference that is not itself just a difference in justification – is an instance of a more general philosophical principle which is helpful for thinking about normative matters. Call it the Principle of Sufficient Difference.⁷

Principle of Sufficient Difference: if there is some normative difference between X and Y, there must be some further non‐normative difference between X and Y that is responsible for this normative difference: that is, there must be some non‐normative feature F such that (i) X has F, (ii) Y lacks F, and (iii) this difference is responsible for the normative difference between X and Y.

Note that the Principle of Sufficient Difference is not itself a full‐blown method for determining which of your beliefs are justified. But it is a principle that any good method you apply with that aim in mind will have to respect. (Consider that a method that did not respect this principle would have to allow, for example, that two beliefs could have all the same properties with the exception that one of them is justified and the other is not. But that would be quite a pill to swallow.)

^1.11 Back to business. With the Principle of Sufficient Difference in hand (along with an intuitive sense that B1 is justified and B2 is not), can you think of any difference between B1 and B2 that might plausibly account for why B1 is justified and B2 is not? If so, you're in a good position to appeal to this very difference when proposing a method for sorting your justified from your unjustified beliefs.⁸

^1.12 But what might such a feature be? What seems to favorably distinguish your belief that rental prices will continue to increase in London in the coming year from your belief that there are ghosts? As you look through the pages of Your Book of Beliefs, you notice a good candidate for such a feature: you find various other entries that support B1. By ‘support’ here, what is meant is: entries that might serve as premises of good arguments, arguments that support B1. For example, you come across these entries:

 B645. There will not be an increase in the supply of housing in London during the coming year.

 B646. There will be increased demand for housing in London during the coming year.

 B87. Price will increase if there is an increase in demand without an increase in supply.

B645, B646, and B87 all support B1. You don't see any other beliefs that support the ghost belief. So here's one difference between B1 and B2: B1 is supported by further beliefs, and B1 is not. Perhaps extrapolating from this difference will give us a good rule for determining which beliefs get to be entries in Your Book of Justified Beliefs:

Supporting Belief Rule: an entry in Your Book of Beliefs gets to be an entry in Your Book of Justified Beliefs iff it is supported by further beliefs.

The Supporting Belief Rule seems like a promising idea until you notice that there's another entry in the book:

 B465789. Your friends at school saw a ghost when they were camping.

You still think that B2 isn't justified, but the Supporting Belief Rule suggests that it is justified – after all, it is supported by a further belief: B465789.

^1.13 The Supporting Belief Rule isn't a good rule. If it's silly to believe in ghosts, it's silly to believe that your friends saw a ghost. If a silly belief supports another silly belief, they remain equally silly, and neither seems to be a good candidate for justification. (Compare: you can't boost the strength of a weak link in a chain by supporting it with another weak link.) The trouble with the Supporting Belief Rule, then, seems to be that it doesn't place any sensible restrictions on which beliefs could confer justification by providing this support.

^1.14 To fix this, we might modify the rule as follows:

Supporting Justified Belief Rule: an entry in Your Book of Beliefs gets to be an entry in Your Book of Justified Beliefs iff it is adequately supported by more justified beliefs.⁹

That's better, surely, for it explains why B2 doesn't get into Your Book of Justified Beliefs. It isn't justified, because the only beliefs that support it are unjustified. Notice, however, that if we move to the Supporting Justified Belief Rule, we face a new and entirely different problem.

^1.15 In explaining why B1 is justified, you cited further beliefs (i.e. B645, B646, and B87). There's a nice little argument that takes you from these beliefs to B1, but the argument doesn't justify B1 unless its premises are themselves justified. So: are B645, B646, and B87 justified or not?

^1.16 The Supporting Justified Belief Rule tells us that we need more justified beliefs (and not merely more beliefs) that support B645, B646, and B87 if these beliefs are going to justify B1. Convinced that B1 really is justified, you press on. Surely something must support B645, B646, and B87. So surely these further beliefs contained in the pages of Your Book of Beliefs will show that B1 belongs in Your Book of Justified Beliefs.

^1.17 The situation we face here is similar to the situation we faced earlier. We notice that there's a normative difference between two things (e.g. B1 and B2). The Principle of Sufficient Difference tells us that such a difference is possible only when there's some further difference that accounts for it (e.g. B1 is supported by justified beliefs and B2 is not). When we cite the factors that distinguish a justified belief like B1 from an unjustified belief like B2, the Supporting Justified Belief Rule tells us that the factors will be more justified beliefs (e.g. B645, B646, and B87). The Principle of Sufficient Difference will apply again to these new beliefs and the Supporting Justified Belief Rule will tell us that we need beliefs other than B645, B646, and B87 to justify B645, B646, and B87 (Figure 1.1). This could go on for a while, in a way that seems to threaten an infinite regress.

Figure 1.1 The Supporting Justified Belief Rule tells us that we need beliefs other than B645, B646, and B87 to justify B645, B646, and B87.

^1.18 It is beginning to look as though demonstrating that B1 is justified (which we originally thought was obviously justified) is difficult to do. And this looks like a problem – what epistemologists call a regress problem. After all, repeated application of the Supporting Justified Belief Rule tells us to find more and more justified beliefs (threatening infinite regress), but perhaps the required stock of justified beliefs just isn't there.

^1.19 One somewhat depressing move at this juncture is to abandon the attempt to show that B1 (or any other of your beliefs is justified) and simply accept skepticism about epistemic justification:

Skepticism about epistemic justification: no beliefs are justified.¹⁰

If skepticism is correct, Your Book of Justified Beliefs is (despite what you may think) empty; none of your beliefs, including B1 and other beliefs you originally took to be justified, are actually justified. Unfortunately, Your Book of Beliefs – the one the scientists gave you – is filled with entries. Its pages should be blank. Or so this view maintains.¹¹

^1.20 Although some serious thinkers have reached this skeptical conclusion,¹² the very idea that your beliefs are unjustified en masse takes us a long way from common sense, which tells us that some of our beliefs are in much better shape than others. Plus, the skeptic hasn't offered any compelling positive argument for skepticism yet, so we shouldn't be too hasty to conclude that none of our beliefs are justified. After all, doesn't the Supporting Justified Belief Rule tell us that justification is within reach? All it takes to have justified beliefs like B1 is to have more justified beliefs like B645, B646, and B87. We haven't seen any reason yet to think that these beliefs aren't justified, have we?

^1.21 In the remainder of this chapter, we'll articulate and critically discuss three non‐skeptical views: infinitism, coherentism, and foundationalism. In outline form, these views maintain the following:

Infinitism: all justified beliefs are justified because of support from further justifiers. The chain of justifiers justifies beliefs only when it forms an infinite series of non‐repeating justifiers. No belief can be justified without support from a further justifier that belongs to such a series.

Coherentism: all justified beliefs are justified because they belong to a coherent set of beliefs that support them (i.e. beliefs that are mutually supporting in that they lend deductive, inductive, or abductive support to other members). No belief can be justified without support from a further justified belief.

Foundationalism: all justified beliefs are justified because of support from further justified beliefs or because they are justified without such support. Any justified belief is either a properly basic belief or it derives its justification from such beliefs.