If we don't think that the possibility of error is what creates the need for justificatory support, we probably wouldn't think that the regress stoppers have to provide certainty. We might think of the justified beliefs as the beliefs that it makes sense to form given the end of forming true beliefs and avoiding false ones, say. On this way of looking at things, the adequacy of evidence doesn't turn on whether it's impossible for this evidence to lead you astray. If it makes truth sufficiently probable or shows that your beliefs are not held arbitrarily, this might be sufficient. The Cartesian might complain that nothing can provide adequate support if it's fallible, but this is one of those issues that we'll have to try to sort out as we work through a range of other discussions in the book. At any rate, the question for the modest foundationalist is whether experience can provide adequate (albeit fallible) support for our beliefs about the external world.
2.11 Now that we have two views concerning regress stoppers on the table, we can turn our attention to perception and perceptual experience. We need to know more about perceptual experience to determine whether it could stop the regress of justification on either of the foundationalist views just introduced.
2.3 How to Talk about Experience
2.12 We need to talk about talking about perception and perceptual experience. You see the page and the words on it. You see the black marks on the page and you see them as words, words that you're familiar with because you're an English speaker. In speaking about perception in the pages that follow, it will be helpful to remember the distinction between seeing something and seeing something as something:
1 Agnes sees the marks on the page.
2 Agnes sees the marks as words.
2.13 If Agnes could read, both (1) and (2) might be true. If Agnes were a dog, she could see the marks but would not see the marks as words. She would lack the requisite recognitional capacities. In this case, (1) would be true, but (2) wouldn't be.
2.14 The difference between seeing the words and seeing these marks as words is epistemically significant. If (2) is true, it should be easy for Agnes to tell that there's a causal process that connects these pages to a speaker of English. If (1) is true but (2) isn't, it might not be all that easy. (Again, if Agnes is a dog or a small child, she cannot rationally or justifiably believe that these marks are strings of English sentences. This isn't because she has trouble seeing them.)
2.15 Whether something you see is seen as being a certain way depends, in part, upon what you see, but also upon whether you have further capacities to recognize what you see as being a kind of thing (e.g. a word, a barn, a cardinal) or an individual (e.g. Agnes, your best friend). By contrast, whether you see something doesn't depend upon how it strikes you or how it registers with you. If you see a building that's a barn that's been disguised to look like a bank, you see a barn but you don't see it as a barn if the disguise is convincing. In this situation, it wouldn't be reasonable for you to judge that the building is a barn unless you had some further information (e.g. an informant who told you about this fiendish plot to disguise barns so that they look like banks). Seeing differs from seeing‐as in that the latter requires capacities to recognize the things you see as being kinds of thing (e.g. English words, barns, a friend's happiness, etc.)4. Still they share something important in common. Both involve awareness of something external to you (i.e. what you see).
2.16 When we see things, things are there to be seen. These things are typically as they seem to be. You see the words on this page and there is a conscious episode in which it seems to you that a white page is covered in black marks. Although it would be very difficult to arrange things this way, you could have had a very similar conscious episode, one that you couldn't yourself distinguish from this present episode, in which things don't go well for you. One possibility might be that there are things that you see, but they aren't as they appear to you to be (e.g. the letters are not black but they appear to be, or the page is not white and rectangular but it appears to be). Another possibility might be that you have a conscious episode that's just like the conscious episode that you're now undergoing where there's simply nothing in the external world that we'd want to say is the thing that you see (e.g. God annihilates this book but causally intervenes to sustain your present experience so that you couldn't notice its absence). The first possibility involves illusion. The second involves hallucination.
2.17 We need a way to talk about the conscious episode that you're undergoing right now without any commitment to whether you see things that are there and see them as they are. We'll call this stretch of perceptual consciousness in which it looks as if there's a book before you an experience and reserve the term perception for just those experiences in which you're aware of some external object. On this way of talking, a hallucination is a kind of experience but it is not a perception. If you see a straight stick that looks bent, you'll have the experience as of a bent stick, but you'll see a stick that is actually straight. This is a case of perception.
2.18 Philosophers find this notion of perceptual experience useful because they want to capture something that's an aspect of perception or a part of perception without saying whether that conscious episode is one of perceiving, suffering an illusion, or suffering a hallucination. It might be helpful to think about the relationship between perceptual experience and perceiving as similar to the relationship between trying and succeeding. In successfully jumping across a puddle, you try to jump across the puddle. In saying that you tried, we aren't saying whether you succeeded or failed. Think of trying as something that successful attempts and unsuccessful attempts share in common. We will use the term “experience” to cover the conscious episodes involved in seeing things (e.g. a chair, a sleeping dog, etc.) and in indistinguishable cases of illusion and hallucination. In so doing, we'll assume that (3) is neutral between things like (1) and (4):
1 Agnes has an experience as of black marks on a white page.
2 Agnes hallucinates and has an experience as of black marks on a white page.
2.19 The difference between seeing and hallucinating is not always obvious to the subject undergoing experiences like (3). When subjects undergo experiences like (3), we expect them to form beliefs about their surroundings in light of these experiences. In cases of perception, we naturally expect that the perceptual beliefs they form will turn out to be true. In cases of hallucination, we don't expect this.5
2.20 It's worth noting that while philosophers often love to use examples involving perfectly convincing hallucinations, it's certainly possible to know that you're hallucinating or to have serious doubts about whether you perceive something or merely hallucinate it. Recall Macbeth's soliloquy:
Is this a dagger which I see before me,
The handle toward my hand?
Come, let me clutch thee.
I have thee not, and yet I see thee still.
Art thou not, fatal vision, sensible
To feeling as to sight? or art thou but
A dagger of the mind, a false creation,
Proceeding from the heat‐oppressed brain?
It seems to him that he sees a dagger, but he cannot feel it. In such a state, it might look as if something is there. But he does not believe it to be there. This illustrates something important about the relationship between perceptual experience and perceptual belief. They are distinct things. A subject can have an experience and not believe that things are as they appear to be. The experience might dispose