Perceiving is using your senses (sight, taste, touch, etc.) to “see” something. But this definition is an oversimplification of the issue, just as “having knowledge” is an oversimplified definition for knowing. These two seemingly different ideas are completely intertwined.
It is true that you see the world with your eyes, but what you see is up to your mind. You can pick a familiar face out of a crowd, or hear your name from across a noisy room. Why is that? Do we go around all day consciously listening for our name or scanning every face for the ones we are looking for? Well, I guess we could but it would seem like a rather large waste of time and energy. So if we are not consciously doing these things than that would suggest that more than our senses play a part in how we perceive the world.
Your preexisting knowledge of something affects how you perceive it. It is this knowledge that makes your ears perk up at the sound of your name, and draws your gaze to a familiar face. Along with affecting what you perceive, this knowledge can also affect how you perceive it.
Your preconceived notions make your senses more attuned to things that support your way of thinking. This affect is the foundation for stereotypes. If it’s in your head that a certain group is suppose to act a certain way, you have a tendency to only notice that group acting in that way. Lets say that you subscribe to the school of thought that believes Asian students are better at math than other races, with this in mind, you would be more likely to notice an Asian kid that got a 98 on his test than the one that got a 78. The first student reinforces the stereotype you believe in, making your senses more adjusted to it. Here your knowledge of the math skills of Asian students has skewed your perception, and in tern, you perception has skewed your knowledge.
You cant really know much, with the exception of 2+2=4, with absolute certainty, yet we seem to think that we know a lot of things. Our knowledge is largely based on our perceptions, and if those can’t be trusted, how can our knowledge be either? Taking the same example as before, by perceiving only the higher math score, you have reinforced your knowledge of the math abilities of Asian students.
It is not just familiar things that can be misperceived due to your knowledge, even your perception of something that you have never seen or heard of before is affected by what you know. When you encounter new things the first thing that brain tries to do is to relate it to other things that you do know or put it into some kind of context. In this sense, even thought you have never come across this thing before, you already know it. And it is this “knowing” that will prevent your senses from objectively perceiving it.
If you wanted “superior” knowledge, you would most likely back up your knowledge with facts. But if you accept that perception is subjective, and knowledge is based on perception, then it would seem that facts, a type of knowledge, would also be subjective. All and all, it seems like a futile pursuit if you ask me.
For further discussion of the topic of knowledge please refer to the quotation from Bill and Ted’s Excellent Adventure over to the side.