For World Philosophy Day, we've asked leading thinkers around the world about the philosophical idea that has had the greatest impact on them, and set their responses alongside the big ideas posited by their recent forebears - renowned philosophers of the twentieth century. Discover the concepts behind the cutting edge of ideas, and trace their evolution through history.

Judith Butler on Hegel

Judith Butler is an American social and political philosopher, and co-director of the International Consortium for Critical Theory Programs, whose first book Subjects of Desire investigated Hegelian reflections in twentieth-century France. Butler has made major contributions to political philosophy, ethics, and literary theory, and her theory of gender performativity is highly influential.

It is probably odd to think that Hegel has something to tell us about our lives, but what if our most basic obligations toward one another and the planet could be illuminated by this early 1800s philosopher? In Phenomenology of Spirit, Hegel shows us that we are not solitary creatures, disconnected from one another, although he knows we sometimes see ourselves that way.  He makes the claim that only as a social being can I begin to reflect upon myself. Only by encountering others do we stand a chance of knowing ourselves, and once we come to know ourselves, we grasp the way in which we are fundamentally tied to others, in a network of living processes.

So if we thought we could know ourselves by turning inward we were mistaken. My life is never mine alone, since it belongs to living processes that exceed and sustain me. I cannot destroy another’s life without attacking the set of living processes of which I am a part. The ethical imperative that emerges is to keep oneself and the other alive. Hegel understands the fury of the individual who wants no one to be like him or equal to him. Yet he leads us to the realization that I cannot do away with this other without also doing away with myself.

For me, reading Hegel illuminated our status as living creatures, our bodily interdependency, and a sense of reciprocal ethical obligation that is also an obligation to sustain the world that makes our lives possible and livable.

Simon Blackburn on Hume

Simon Blackburn is an English academic philosopher best known as the proponent of quasi-realism in meta-ethics. He has made major contributions to the fields of meta-ethics and the philosophy of language.

The greatest of British philosophers, David Hume thought that belief in God was both uncertain, and useless. Uncertain because ordinary reasoning from experience could not guide us reliably into the misty regions of theology. Useless, because even if we thought we could obtain reasonable belief in such an area we could not properly infer anything from it. If we wished to know what God planned for the world, we would have to look at the world as we have it. If that is not very nice, then we must resign ourselves to a God that makes not very nice worlds.