The specific type and behavior of the receptors in our eyes determine the wavelengths that we can - and can’t - see. The shapes and structures in our ears determine the frequencies we can - and can’t - hear. And our expectations drive how we experience the world. Our senses and the parts of our brain that interpret them are our first filters. 

There are countless sights, sounds, and smells in the world that we are oblivious to, simply because we don’t have the senses to detect them. On the other hand, our senses can often detect things that aren’t actually there and distort the things that are.

In isolation, we call these optical or auditory illusions, but they parallel our broader tendency to make rapid inferences about the world. They show that often, even at a biological level, we experience things based on what we expect them to be.

This parallels the way the entire brain works. While we can’t change our senses, knowing their tricks may change what we do with the things we think we know.