Epistemological Disjunctivism and the New Evil Demon

The intermediate tier left the internalism and externalism debate at a standoff. Externalists, reliabilists above all, said that what makes a belief justified is that it was formed by a process that tends to produce truths, whether or not the believer can tell. Internalists said that justification must be something the believer can, at least in principle, discover by reflection. Each side had a case the other could not handle well. For externalism, the hardest was the one this article begins with.

The new evil demon problem

Descartes' demon was used to threaten knowledge: if you cannot rule out the demon, how can you know anything about the external world? The new evil demon puts the demon to different use. It grants that the demon's victim does not know. The question is whether the victim is justified.

Imagine your exact internal duplicate. They have your memories, your experiences, your reasoning habits, and they form beliefs in response to those experiences just as you do. The difference is that their experiences are produced by a demon, and none of their perceptual beliefs is true. When you see a cup and believe there is a cup, they have a cup-like experience and believe there is a cup, but there is none.

Is your duplicate justified? Most people who consider the case say yes. Their beliefs are as reasonable as yours. They are responding to their evidence exactly as they should. If you would call your belief justified, you should call theirs justified too, since from the inside there is no difference. What they lack is luck, not rationality.

Reliabilism says otherwise. Your duplicate's perceptual processes produce false beliefs nearly all the time. By the reliabilist's lights, they are not justified.

The reliabilist has tried several repairs. Alvin Goldman proposed in 1986 that reliability be assessed in the normal worlds, those that match our general beliefs about the actual world, rather than in the world the subject inhabits. Ernest Sosa distinguished two kinds of justification, one tied to the reliability of faculties in the subject's own environment and one to their internal coherence. Each repair concedes something to the internalist, and none has become standard.

The internalist's dilemma

The internalist verdict on the demon case seems right, but the internalist position has a cost of its own.

If the justifying factors must be reflectively accessible, and you and your demon-deceived duplicate are reflectively indistinguishable, then you have the same justification. That is how the internalist gets the right answer about the duplicate. But it follows that your justification for believing there is a cup is no better than the duplicate's. Your reason for believing there is a cup must be something both of you have, such as the experience of seeming to see a cup. And that reason does not entail that there is a cup, since the duplicate has it and there is no cup.

This means that for the internalist, your perceptual reasons are always compatible with your being deceived. No perceptual reason you could have would guarantee its conclusion. The sceptic then argues that since your reasons do not rule out deception, they cannot give you knowledge. Internalism about justification seems to lead directly to the view that perceptual knowledge is at best inferential from appearances, which is where the sceptical problem started.

So each side has a problem. The externalist can explain how perception gives knowledge, but gets the demon case wrong. The internalist gets the demon case right, but at the price of making every perceptual reason fall short of the truth.

Epistemological disjunctivism

The disjunctivist denies the assumption the internalist and the sceptic share: that you and your deceived duplicate have the same reasons. You have seen that there is a cup. Your duplicate has merely seemed to see a cup. These are different states. The first is a factive reason, which entails there is a cup. The second is not.

The name comes from the claim about how to describe the common case. When you and your duplicate both appear to see a cup, what the two of you have in common is not a shared experience that falls short of the fact. It is a disjunction: either you see that there is a cup, or it merely seems to you that there is. The disjunctivist says there is no more basic shared state underneath. The good case and the bad case are simply different.

McDowell introduced the idea in 1982 in a paper on criteria and defeasibility. Pritchard developed it into a full epistemological position in his 2012 book. The distinctive claim is not just that seeing that p is factive, which externalists and Williamson accept. It is that the subject can know by reflection that they are seeing that p. In the good case, your reason is both factive and accessible to you.

If this is right, the dilemma dissolves. Like the externalist, the disjunctivist says your perceptual reason entails its conclusion, so there is no gap between reason and fact for the sceptic to exploit. Like the internalist, they say your reason is accessible to you by reflection, so you are not dependent on facts you cannot see. The demon victim has a worse reason than you, but is not blamed for having it, since from the inside they could not tell.

What happens to the demon case

The disjunctivist has to say something about the victim's justification. Pritchard's answer draws on a distinction the knowledge-first article already introduced.

The victim is blameless. They have done nothing wrong, since they are responding reasonably to how things seem to them. But their rational support is worse than yours. They have only a seeming, not a seeing. This lets the disjunctivist accommodate the intuition that there is something epistemically admirable about the victim, while denying that the victim is as well supported as you.

Critics say this concedes too little to the new evil demon intuition. The intuition was that the victim is equally justified, not merely blameless. Pritchard replies that this intuition is a product of the internalist picture, which assumes the victim and the normal subject have the same reasons. Drop that picture and the intuition loses its grip.

The access problem

The most pressing objection is that the disjunctivist's key claim seems false. How can you know by reflection that you are seeing a cup, rather than merely seeming to see one? Whatever reflection reveals to you, it would reveal to your duplicate too, since reflection is internal and you are internally the same.

Pritchard's reply targets the first premise, or rather the idea that it supplies an alarming kind of a priori knowledge. What reflection gives you is knowledge of what your reason is. That knowledge is reflective, but its object, the fact that you see a cup, is an empirical fact. You come to know there is a cup by seeing it; you then know by reflection that your reason for believing there is a cup is that you see it. The empirical knowledge is prior. Reflection does not deliver facts about the world on its own; it delivers knowledge of what kind of support one already has.

A second part of the problem is the distinguishability objection. If you can know by reflection that you are seeing rather than seeming to see, you should be able to distinguish the two situations by reflection. But you cannot; you cannot tell by introspection whether you are dreaming or deceived. Pritchard answers by separating two things: discriminating between situations and favouring one over another. You cannot discriminate the good case from the bad, but you can have a reason that favours the claim that you are in the good case, namely that you see you are. The disjunctivist's reasons do not help you tell cases apart, but they do give you something the sceptic says you lack.

The highest-common-factor view

The disjunctivist's target is sometimes called the highest-common-factor conception of experience, in McDowell's phrase. On this conception, whatever reasons you have in the good case are exhausted by what you share with the bad case. The good case adds nothing epistemically, only the external fact that the experience happens to be veridical.

The highest-common-factor view is attractive because it seems obviously true. How could your reasons depend on facts you cannot detect? The disjunctivist's answer is that the view begs the question. It assumes that what you can detect is limited to what the demon victim can also detect. But in the good case you detect the cup; that is what seeing is. The fact that someone in a different situation would be misled does not show that you are not detecting what is there.

Assessment

Epistemological disjunctivism is neither internalism nor externalism, and advocates present that as its main virtue. The more cautious view is that it is a form of internalism with a much broader conception of what is reflectively accessible. The view's fate depends on whether one accepts that seeing is a state one can reflectively recognise, and that question is not settled by argument alone.

Next

Why knowledge seems more valuable than true belief, and why reliabilism has difficulty explaining this.