Perhaps the simplest test for separating truth from falsehood is to focus upon that which is real: if something corresponds accurately to reality, then it is true. If it doesn’t correspond accurately to reality, then of course it must be false. Easy, right?
This is probably the sort of test that most people intuitively want to use, and if you ask them how they distinguish truth from untruth, they may offer something along these lines as an explanation. There’s just one problem: how do you tell what corresponds to reality and what doesn’t? After all, it may be nice in theory to assert that beliefs which correspond to reality are the true beliefs, but unless we have some means for identifying the beliefs which do so correspond, our test will remain just that: theory.
Now, there’s certainly nothing wrong with having a theory — indeed, what was just described is essentially the Correspondence Theory of Truth. One of the criticisms of that theory is also the criticism just raised: we need more than a theory about the nature of truth. What we are looking for here is some means of figuring out which of our beliefs are true and which are not. Nothing else qualifies as a criterion of truth.
A common and obvious choice here usually goes under the name Naive Realism. According to this perspective, our senses reliably produce accurate information about the world around us — and, moreover, that these are the only means that we can regularly trust. So, whatever information we receive from our senses accurately describes reality and any beliefs which correspond to the data from our senses must therefore be “true.” Beliefs that don’t correspond with that data are therefore false.
There are a lot of problems with this view — it’s not called “Naive” Realism for nothing, after all. For one thing, we know for a fact that our senses don’t always produce 100% accurate information about the world around us. A variety of factors can contribute to errors in what we perceive and how we perceive it. A simple example of this would be the fact that when we put a stick part way into the water, we perceive it as bent because of the way the light interacts with water.
Adopting the perspective of Naive Realism might incline us to accept the information of our eyes as accurate, but that would be a mistake. The stick isn’t really bent. Other optical illusions can be more complicated, and that doesn’t even begin to touch upon the fact that our perception of the world isn’t always unmediated — it isn’t as if information goes directly into storage in the brain. Our expectations, assumptions, and past experiences all combine to affect what we perceive.
Another problem with Naive Realism is that it commonly ignores the possibility of determining the truth of ideas through means that aren’t directly through our senses. We have devices, for example, that can provide us with information about objects that are too small to see, too far away to see, that make sounds too high-pitched to hear, and so on. If we relied only on our ability to use our senses to immediately perceive the world around us, we would have to disregard such data — that, however, would be a mistake.
None of this should be taken to mean that Naive Realism is valueless or that its premises should be discarded completely. It’s not so much that our senses are unreliable (if they were, how could we survive?) but rather that they aren’t perfectly reliable and need to be verified by other sources. By itself, Naive Realism is a poor means for separating true beliefs from false beliefs — we need something more that allows us to move beyond our immediate sensations.
