Through reading the chapter, I found it really interesting how even though a person is blind, they still need the presence of light to be on their retinas to trigger internal processes that regulate the sleep-wake cycle and in order to avoid depression. But even with light we can be blinded if we are exposed to too much of it, too much than our eyes can handle, just as if we were in the complete darkness. Too much of light or of darkness can cause us to become disoriented and blind. I also found it interesting how the color that is produced by light can be used to represent emotions as well as the four elements. Often times we relate red with anger and fire, blue with sadness and water, green with envy and earth, and yellow with cowardice and air. While these emotions may not match up with the element with which they are paired with, it is still amazing to see how something that is produced from light is used to connect with certain things in our environment and with the feelings within us.