C.S. Lewis began a sermon in 1941 war-time Oxford students by remarking, “If you asked twenty good men today what they thought the highest of the virtues, nineteen of them would reply, Unselfishness.” Lewis argues, and I agree, that in reality the highest virtue is Love. At the top levels of American society in 2016, it seems to me that the virtue of Unselfishness has been thoroughly replaced with Tolerance.
In principle, Tolerance & Unselfishness are different manifestations of the same ethical orientation. The question being asked is, “How can I not hurt others?” Unselfishness answers the question in terms of how I as an individual might not be a burden to others, whereas Tolerance answers it in terms of how I might not infringe on the rights of others.
Unselfishness is about submission of self. Tolerance is about permission for others.
It may seem as though Tolerance is an advancement in the right direction, since it is more other-oriented. The Tolerance of today avoids numerous atrocities that have been committed during the reign of Unselfishness, such as the disastrous hormonal treatment for homosexuality given to the likes of Alan Turing in 1952, memorably depicted in the 2014 film The Imitation Game. If Turing were alive today, he would certainly not suffer the same fate.
At the same time, the Turing case demonstrates an important similarity between Tolerance & Unselfishness, which is that while the latter is principally self-oriented, it has very concrete ramifications for others when applied at the social level. In other words, “If you are not willing to unselfishly submit to the order of our society by refraining from certain acts, we will help you to do so by force.”
Tolerance, though other-oriented in principle, has equally concrete ramifications for individuals when applied to society at large. The student-led skirmishes between free speech & safe space at Yale & Missou last fall, for example, suggest that Tolerance can and will commit the same atrocities as Unselfishness in the next generation. It is the same logic as the Turing case: “If you are not willing as to subscribe to the social virtue of tolerance, then we will help you do so by force.”
As Lewis wrote, Love is at the center of Christian virtue. Love is both unselfish & tolerant, but it is not exclusively so. Love cannot tolerate it when you hurt others or yourself, nor is love unselfish when that means withdrawal from pain and suffering. The difference is that Unselfishness & Tolerance are both essentially negative, whereas Love is positive and dynamically other-oriented. Love is being-for others as Christ was and is for us.
The question, “How can I not hurt others?” is a noble attempt to practice the Hippocratic Oath: "Do no harm." As wise men & women have pointed out through the centuries, though, every "Thou Shalt Not" is the negative expression of something that must also be understood positively, which means that a negative ethic can only ever be partial at best. The positive side of "Do no harm" (cf. Ex. 20) is given in the Bible as Love: "Love one another" (Jn 13:34) and "Love your neighbor as yourself" (Lev 17:18) and "Love the Lord your God with all your heart and might and strength" (Dt 6:5).
Lewis prescribed an antidote for his Unselfish compatriots that we would probably do well to take: the cultivation of promise-oriented hope in God’s future for the world. That world, as the Bible affirms it, (e.g. Rev 21–22, Is 65) is characterized by peace, fullness of joy, and justice. It is a renewed heaven and earth which is so real that our present existence will be remembered as a mere shadow of the true life we shall know then. Love is the thread runs from here to there because, as Paul writes, it is the one thing that never ends (1 Cor 13).
 C. S. Lewis, The Weight of Glory: And Other Addresses (New York: HarperOne, 2001), 25.