When we discover that we have been wrong, we say that we were under an illusion, and when we no longer believe in something, we say that we are disillusioned. More generally, analogies to vision are ubiquitous in the way we think about knowledge and error. People who possess the truth are perceptive, insightful, observant., illuminated, enlightened, and visionary; by contrast, the ignorant are in the dark. When we comprehend something, we say I see. And we say, too, that the scales have fallen from our eyes; that once we were blind, but now we see.

This link between seeing and knowing is not just metaphorical. For the most part, we accept as true anything that we see with our own eyes, or reg­ister with any of our other senses. We take it on faith that blue is blue, that hot is hot, that we are seeing a palm tree sway in the breeze because there is a breeze blowing and a palm tree growing. 

We are all prone to regarding the ideas in our own heads as direct reflections of reality, and this particularly true in the domain of perception. Heat, palm trees, blueness, breeziness: we take these to be attributes of the world that our senses simply and passively absorb.

For a different example of the utility of interpretation, consider your blind spot—the literal one, I mean. The blind spot is that part of the eye where the optic nerve passes through the retina, preventing any visual pro­cessing from taking place. If perception were just unembellished sensation, we would experience a chronic lacuna where this nerve interrupts our visual field. Buv we do not, because our brain automatically corrects the problem through a process known as coherencing.  

No matter what these processes do, though, one thing remains the same: we have no idea that they are doing it. The mechanisms that form our perceptions operate almost entirely below the level of conscious aware­ness; ironically, we cannot sense how we sense. And here another bit of meta-wrongness arises. Because we can’t perceive these processes in action, and thereby take note of the places where error could enter the picture, we feel that we cannot be wrong. Or, more precisely, we cannot feel that we could be wrong. Our obliviousness to the act of interpretation leaves us insensitive—literally—to the possibility of error.