There seems to be a paradox in the nation’s thinking about privacy. On the one hand, people want it; they are going ex-directory in increasing numbers because of mobile databases and they object to their houses being visible on Google Earth. On the other hand, millions are splashing their thoughts, personal details and pictures on to social networking internet sites and tweeting to whomever wishes to read. But the self-publicising mania of Facebook and the like is mostly about projecting an image, not revealing truths. Not many teenagers who appear daily on YouTube would choose to take the webcam into the loo with them or reveal their address for fear of the weirdos who prowl cyberspace. The internet is more comparable to the schoolyard than the bathroom, which shows that the apparent self-baring of chatrooms and blogsites is not quite as privacy-destroying as it seems.

There is good reason for this. Privacy is an important possession. People need a psychological space where they can be in touch with themselves, deal with feelings, sort out thoughts.

If we lived naked in glass houses with our every thought broadcast to the world, we would be as prisoners trapped in the glare of others’ scrutiny, unable to grow, think, relax or relate to others. Even the temptations to self-revelation that today’s electronic media offer will not overcome the desire for genuine privacy that remains as an instinct in almost all of us.

A.C. Grayling is Professor of Philosophy at Birkbeck, University London