But there is another, more suspect, conception of individual autonomy, sometimes associated with the progressive secularisation of our culture. This is the fantasy of humanity as somehow "self-creating", in the sense that we should be able to generate our own values by an act of will. In this fantasy, there are no objective values, merely projections by human beings of their own individual preferences. Friedrich Nietzsche, who is perhaps the most significant promoter of this idea, seems to have supposed that humans (of an exalted type) could somehow create meaning and value for themselves by a grand volitional act - a notion that involves serious confusion. I cannot, of course, make something valuable by choosing or willing it (as if I could make cardboard nutritious by deciding to eat it). Indeed, this idea precisely puts the cart before the horse, since in reality my choices or acts of will can be worthwhile only in so far as their objects already have independent value.

The idea that we should create our own values was associated by Nietzsche with the death of God. Once human beings abandon the idea of an objective and eternal guarantor of value, there is no recourse but to do the job ourselves. Each of us has to tread the lonely path of the "new philosopher", as Nietzsche puts it in Beyond Good and Evil (1886), someone with a spirit "strong enough to revalue and invert eternal values".

Apart from the arrogance, the near-insanity, of this fantasy, there is the logical problem I've already referred to: it simply can't be done. We are not gods (and arguably even if we were, we could not create value by some kind of fiat of the will).

Could society fill the gap that the isolated individual cannot plug? This brings me back to Descartes and the meditator pursuing his lonely, isolated search for truth. Much of philosophy in the last 60 years has been engaged in a sustained attack on this Cartesian idea of a solipsistic, individual quest for knowledge. Ludwig Wittgenstein was the most prominent champion of the attack when he lambasted the "Cartesian privacy". Thought and language, for Wittgenstein, are inherently public, socially mediated phenomena. So it is a radical confusion to suppose that an isolated individual could construct knowledge from the inside outwards. Even in the supposed starting point, the Cogito, even in thinking and reflecting and doubting, the very fact of my using thoughts and concepts already implies that I am part of a public, language-using community.