I teach a number of Ethics courses each semester. These courses are very enjoyable for me, and I hope for my students as well. Each time I introduce an ethical theory I look for its foundational principle: its central proposition from which it determines the rightness or wrongness of particular actions. For instance, Libertarians ground all of their determinations about what is right and wrong in a principle of self-ownership, Deontologists in a list of universal moral rules, Utilitarians in the greatest amount of happiness that can be produced, Human Rights Theorists in some list of basic rights.
The problem with all of this is that it is terribly abstract. Traditional moral theories propose a solution to the problem or right and wrong that fails to take into account the genuine motivation behind human goodness. Conceiving of morality as something like a math problem to be solved by the dry and impersonal calculations of reason, such theories forget that our our initial impulse toward acting morally is concern for and empathy with our fellows.
Compassion for others (be they human or animal) is the fire from which morality burns. The reason we strive to be good is that we care about others. We desire to help them, to keep them from harm, to accord them the same treatment we would like for ourselves. Without this initial compassion for others, the spark of morality fails to ignite and considerations or right and wrong are not possible.
Consider the activities of the most deranged among us: Do mass shooters, serial killers, and other sociopaths care for others? Clearly they do not. Could the SS guards have had compassion for their Jewish prisoners? The American slave-owners empathy for their slaves? Perhaps there was a flicker here and there, but without ignoring, repressing, or just plain not having the natural impulse to feel for others pain and rejoice with them in their happiness, they could not have acted in the reprehensible and inhuman manner that they did.
The origin of morality is feeling, not reason. Furthermore, it is not feeling for humanity in the abstract, but feelings for others that we actually encounter, that we actually have relationships with, that creates morality. Unless we start here, until moral theories take as their departure the central role of feelings and relationships in creating morality, we cannot hope to provide a satisfactory account of right and wrong.
This is not to say, however, that reason is irrelevant or unimportant to morality. Reason is extremely important, It is not enough to feel compassion, we must think out how best to demonstrate our compassion. We will encounter conflicts in our relationships with others and we need reason to manage them.
We cannot figure out how to act morally without reason. But reason cannot provide the initial burst that makes us moral. Without a feeling of solidarity with others, reason is a cold, calculating tool; capable of helping the Nazi gleefully persecute his victims or the serial killer calmly stalk his prey.
Where the feeling of compassion and solidarity with others is absent, there can be no morality. When it is present, there must be.