Long ago there was a French guy name Rene. Rene wondered to himself, “What do I know?” and began to deconstruct his knowledge.
Rene realized that most claims of knowledge are grounded in sensorial input, i.e. you see the sun and so claim knowledge that the sun exists. You hear your mother’s voice and so claim knowledge of its sound. You touch burning stick, and so claim knowledge that burning your skin hurts. Rene was not convinced that his justification was sufficient for the claim however, as the senses can deceive. If you see a tornado, what ensures that you are not dreaming it? If you smell popcorn can you be sure it isn’t a hallucination? If you see your friend, isn’t it possible you’re just wrong?
To illustrate this argument forcefully Rene asks the reader to consider a scenario. In this scenario all that exists in the universe is your mind and a demon. The demon is manipulating your mind, causing it to ‘sense’ all that you experience. So the demon causes your mind to hear friends and families, to smell eggs and gasoline, see the sun, all of it, but all the while all that actually exists is the demon and your mind. Since in that universe your experiences would be identical to the experiences you have in this universe, you can’t know for sure that that universe isn’t actually this universe, i.e. you can’t know that you aren’t being entirely deceived by your senses in regards to everything, which means you can’t claim knowledge of anything. Except, Rene continues, that you exist, for no demon, no matter how powerful, could convince something that doesn’t exist that it does. So, as you can think you experience the world, that you can think at all, is sufficient justification for knowledge that, if nothing else, you exist. You think, therefore you are. Everything else? Impossible to know.
That was a long time ago, and there hasn’t really been a solid counterargument. More contemporary epistemologists suggested that knowledge of a proposition consisted of belief in that proposition, justification for that belief, and truth of the proposition. That really just moved the mystery though, what is justification anyway? Furthermore this dude Edmund Gettier blew a hole in that idea mile wide anyway.
Gettier was a professor of philosophy somewhere who hadn’t published anything, or at least not in a while. The admin said he should, so he wrote a three page paper showing that true, justified belief was not sufficient for knowledge. Imagine you come hoime, you see your mom standing in the kitchen ,and so you think, “My mom is home.” As it turns out, what you are looking at is a hologram, however, your mom is home, just in a different room. So you believe the proposition that your mom is home, it’s true your mom is home, and the belief is justified by the fact you see your mom, but it sure doesn’t seem like you know your mom is home. Another scenario like this, you are driving through farmland, barns everywhere. What you don’t know is that there are way more barn facades than actual barns, just movie set barn faces being propped up from behind with sticks. As you drive you catch a glimpse of one of the very few actual barns and think, “That’s a barn.” You believe it’s a barn, it is a barn, and it is, again, justified by having seen it. Again though, doesn’t seem like a barn.
So what the hell? How can you know anything? No worries my friend, I got you. As long as your cool with not knowing whether you know anything, I think you might know all sorts of stuff. Or maybe nothing, but who cares?
I propose that you have knowledge of a proposition when the proposition is true, you believe it, and your justification is grounded in the truth of the proposition. By the last bit I mean your evidence could not exist unless the corresponding proposition was true. This solves the Gettier issue and Rene’s whole deal as well.
Let’s look at Gettier’s examples first. In the mom scenario, you don’t know your mom is home, because the evidence isn’t grounded in your mom being home. She is, but that’s just a coincidence, you saw a hologram and so you don’t know your mom is home. You would have believed she was home anyway. In the barn scenario you do know that that is a barn because you saw the barn, and it is a barn. If you hadn’t seen that barn you would not have believed it was a barn, because you didn’t see it. If you had seen a barn facade you might have believed it was a barn and you would have been wrong, but that’s irrelevant. You see a barn, it is a barn, you believe it’s a barn, and so you know it’s a barn.
In regards to Rene and his whole thing, well if it is a demon making everything up, then you don’t know anything. Not much of a surprise there. If you see something and it is a hallucination, a dream, a mistake, then you don’t know that thing, but if it isn’t, you do.
The cost of this position is that you never get to know that you know. It has to be the case that not only is the relevant proposition true, but that your justification couldn’t exist without that proposition being true. How do you know if your justification is grounded in the truth of the proposition? You don’t. So you can say, “I know blah blah blah” about whatever, and you might be right, and you might be wrong. C’est la vie! That was already the case anyway.
So, as to an epistemological problem you probably didn’t know existed, it’s solved already. You’re welcome.
(I’m probably wrong though).