Seeing this beam of light, and meditating on it Lewis says that we have to see things from many different angles before we are able to understand that which we are observing or feeling. Lewis uses the example of being in love. Looking "along" the beam, you must have been in love at one point in order to really understand what it feels like. When you are in love you can feel the love and the pain and love entails. When you are looking "at" the beam of light in love, you see the psychological happenings, such as the neurons and hormones. In order to fully understand the things that people are feeling you must look "along" their issue instead of just looking "at" the issue and try to figure out what the person in feeling or experiencing.
Lewis also touches on how we need to stop brow-beating. When we engage in this activity we think that we are right just based upon our experiences. It is hard to understand what a person is feeling just by looking at them. Some people continually attempt to go back and understand what things mean or question why someone is feeling the way that they are. We need to understand that there are other ways to see things, and we need to take both into account.