There are many things, aside from surfing, that we may care about, and many ways of caring. We care about people, ideals, places, sports, activities and non-human animals. Within these categories, and undoubtedly others, we have particular objects of care. We have friends, loved ones and close acquaintances. We care about justice or equality or decency or duty or happiness or some combination of these. We might care about Peru or England or Japan or Brunei or Sierra Leone or Norway. Basketball, hockey, curling, handball and baseball are all objects of care for many. And we care about our pets or our environment or the Brazilian rain forest or the continued existence of Siberian tigers.

Moreover, across these particular objects of care are different kinds of caring: love, concern, rooting (in the case of sports teams), enjoyment, pride, protectiveness, and the various forms of engagement that these and other types of care involve.

The objects and types of care listed here – along with many others you undoubtedly thought of while reading these – although extensive, don't capture the most significant aspect of care. Care is what ties us most profoundly to the world. It is our way of binding ourselves to the world through our passionate engagement with particular things in particular ways. It reveals who we are by revealing our most important relationships with what is outside of us.

And even to use the phrase “outside of us” doesn't capture the pervasiveness of the world through our caring. In caring, not only do we reach out both emotionally and behaviourally to the world; the world reaches into us. Our caring happens out there, to be sure. But it also happens in here, where my thoughts and my emotions are born and nourished. It is the profoundest form of commerce between me and the world in which my life takes place. Were there no caring, both me and the world would be diminished, impoverished in numerous ways.

This book has been only an introduction to the philosophy of caring. But the philosophy of caring is, in many ways, itself only in its infancy. Frankfurt's writings on care date from the early 1980s, as does care ethics.