Here’s one standard way to formulate the skeptical paradox.
- I know that I have hands.
- I don’t know I’m not a brain-in-a-vat.
- If I don’t know that I’m not a brain-in-a-vat, then I don’t know that I have hands.
These three sentences cannot all be true, and yet each one seems plausible. Here are the standard replies.
The Standard Replies
Option One: Skepticism
We deny (1.)Option Two: Dogmatist
We deny (2.)Option Three: Closure Hater
Most people think that knowledge is closed under entailment. If we deny that, we’re in a position to deny (3.)Option Four: Contextualist
Utterances of (1.) and (2.) are never true in the same context. Which of the two we deny will depend on the context in which the sentences are uttered.
All of these responses treat the knowledge relation (or relations if you’re a contextualist) as binary relations between a person and proposition.
Enter Contrastivism
Contrastivism holds that knowledge ascriptions do not express a binary relation. Knowledge ascriptions express a ternary relation between a person, a proposition, and a second contrast proposition. (see Contrastive Knowledge.)
I won’t get into the details of the constrastivist resolution of the paradox just yet, I’m more interested in a passage from Schaffer criticizing the skeptic and dogmatist.
I object to skepticism and dogmatism on two parallel counts. First, the denials of [1] and [2] strike me as absurd. At least, some explanation is needed of their plausibility. Second, skepticism and dogmatism collapse distinctions. Suppose that Student, Assistant, and Professor are visiting the zebras at the zoo. Student is remarkably ignorant, and can’t even discern a zebra from a mule; Assistant can discern a zebra from a mule by its stripes, but cannot discern a zebra from a cleverly pained mule; Professor can discern a zebra even from a cleverly painted mule by anatomical features that no mere paint job can disguise. The skeptic confuses Student with Assistant, denying that either knows that the beast is a zebra, since neither can eliminate the painted mule hypothesis. The dogmatist confuses Assistant with Professor, maintaining that both know that the beast is a zebra, since both can eliminate the unpainted mule hypothesis. Both skepticism and dogmatism thereby distort partial knowledge. [emphasis added]
I’m interested in the last few sentences. My money is on dogmatism, so maybe I’m missing something rather simple here. Why can’t the dogmatist capture intuitions about partial knowledge in the following way?
A. The student doesn’t know it’s a zebra
B. The assistant knows it’s a zebra, but the degree of justification (or warrant) is moderate.
C. The professor knows it’s a zebra, and the degree of justification (or warrant) is really high.
The basic idea is that I would not need contrastivism to capture any intuitions that someone like Schaffer has about partial knowledge – all I would need is that justification (or warrant) comes in degrees. Am I overlooking something here?
Additionally, I don’t think that it is any major breakthrough to state that skepticism has issues with knowledge. Obviously, if you deny (1), you are violating common intuition about knowledge. Skepticism is not hurt any more after writing this paragraph than before it, he just points out something that we all know no one likes about skepticism anyway.