There are two types of order that exist. There is the established order of things. Examples of this would be ranks in the military. A private always answers to a Lieutenant and everyone always answers to a General. Or, in a business, there are established hierarchies of bosses up a ladder of power. The other kind of order is informal. It is not established on paper or even vocalized in any orderly form. It exists primarily in our own minds.
Lewis would say that both types of order are necessary and niether one is better than the other. The less formal of the two, however, stems from our desire to belong. This is our desire to be a part of the "inner ring". We want to be wanted and included in something. It is inherent in our nature. I believe that this order stems completely from this desire that is always present in our nature.
Our desire to belong to the "inner ring" is not a bad desire. It will never be satisfied, however, by things of this world. We will never be a part of the inner ring until we do not desire it especially since there is always a deeper part of the inner ring to reach. Therefore, to become satisfied by the inner ring it is completely necessary to find our belonging in the Kingdom of God and fulfill our desire there.