Sosa’s latest account of safety is:
S’s belief that p is safe iff S holds it on a basis that this belief would not have without being true.
He offers this new account to avoid the Kripke red-fake/green-barn counterexample. Here’s how it works with that case. S believes that there’s a green barn in the field, and deduces that there’s a barn in the field. In that case, the first belief is safe, having a perceptual basis, and the second is safe as well, have a deductive basis. Had S simply formed the perceptual belief that there’s a barn in the field, however, it would not have been safe.
What’s interesting is Sosa’s explanation of the intuition that we don’t know that the object in the field is a barn. We have that intuition, according to Sosa, because of the way our perceptual phenomenology works: we are appeared to barn-in-the-field-ly, and also are appeared to greenly, so that the basis of the belief that there’s a barn in the field is the first appearance state. Were the phenomenology different, so that we are appeared to green-barn-in-the-field-ly, no violation of safety would occur either for the belief that there’s a green barn in the field or that there’s a barn in the field.
To appreciate Sosa’s proposal, we must first distinguish between what is in our visual field and what we attend to within this field. It is possible for one’s visual field to contain a green barn, and yet one attend only to the barnishness of the experience. But Sosa needs more than this point. He needs there to be a distinction between unified noticing or attending, where one attends to the green-barnishness of the experience, and conjunctive noticing or attending, where one attends to the barnishness of the experience and in a separate attending, to the greenishness of the experience.
I can make sense of sequentially noting the barnishness of an experience and the color of it. I can also make sense of simultaneously noticing two aspects of my experience, where one part has a property and another part has a different property, such as when there are two objects in my visual field. But I’m not convinced that I abstract away from color in a way that would result in a simultaneous, independent noticing of the greenish character of my experience of an object and the barnishness of that same object.
Suppose we let this point go, however. Even so, I don’t see why one phenomenological account over the other should somehow indicate a difference in safety. I know that the account above implies that they are different, but I don’t see why we should accept that. Take two barn-believers, one of whom has the conjunctive abstraction experience Sosa indicates, and the other of whom has a unified experience. I don’t see why that should make a difference as to whether either knows, and I’m pretty strongly inclined to think that neither knows. Either way, however, if safety is necessary for knowledge, we should expect an adequate account of safety to treat them the same.