There are none so empty as those who are full of themselves. Those who live for themselves are those that live in vain. B. Living Selflessly. Look not every man on his own things, but every man also on the things of others. In Physics there is what is known as Centripetal force and Centrifugal force.
Centripetal force moves inward with everything directed toward the center.
Centrifugal force moves outward with everything directed toward the circumference. When we look at our own things and live selfishly we live centripetally. But when we look on the things of others we live centrifugally. When Paul spoke of esteeming others better than themselves he is not saying that PhD's should defer to freshman, Elders to novices, Parents to children, Generals to sergeants, but is speaking of an interest in promoting others, encouraging others, and caring for others. There are some things in which one is better than others.