We must believe, but we can't believe. Perhaps this is the tragedy that some of us see in Obama: a change we can believe in and the crushing realisation that nothing will change.

For me philosophy begins with these experiences of disappointment: a disappointment at the level of what I would think of as "meaning," namely that, given that there is no God, what is the meaning of life? And, given that we live in an unjust world, how are we to bring about justice?

The culture of irony is the culture of postmodernism, which I would furiously want to denounce. We have to act ethically and politically. Irony is a defensive position, against reality. It always knows what to think about reality. The idea of commitment and engagement is central to me, which is not ironic.

The thing about humour is that the super-ego is also at play, so what interested me, particularly in the last chapter which is key to the book -and no one seems to have picked this up in writings on Freud - is that, in the later Freud, the essence of humour is the ability to look at myself and find myself ridiculous. That makes me laugh.

Melancholia for Freud is the relationship that the subject takes up with respect to itself from the position of what he calls conscience or what he later calls the super-ego. And that can be lacerated - if you think of the anorexic who sees themselves from the perspective of the image they have, of the image they have of themselves in the mirror which is false - that would be the super-ego. Super-ego is what generates depression and it is what has to be dealt with in psychoanalysis.

I guess what happens to a lot of people as they get older is that they get more conservative, but with me, the opposite is the case.

There's a floating distraction in the contemporary world, life at a distance enabled by technology. I want people to commit at the level of their subjectivity. The idea of subjective commitment is at the core of ethics, something that divides the self from itself. I become an ethical self. I cannot meet that ideal, I cannot fulfill it, it divides me from myself and it makes me strive harder. This ideal subjective ethical drive is at the heart of an absolutely earnest, radical politics that insists that people will be able to engage with each other, and they're lifted from irony at that point.