Wittgenstein's emphasis on the social dimension of language harks back to an interpersonal strand in Kant's philosophy. Despite Kant's emphasis on autonomy, my individual rational will is, for Kant, constrained by the fact that I am in a community of similarly rational agents: it is only rational for me to will a certain course of action on the assumption that everyone has similar authority to exercise their own will in a like manner. So Kant's project implicitly rejects Cartesian "privacy". What Kant calls the "tribunal, which will assure to reason its lawful claims" is from the start a public tribunal. Modern philosophy comes of age as the Cartesian "I" gives way to the Kantian "we".

Let us draw the threads together, before seeing how far this Kantian line can get us. First, we have the Cartesian ideal, that each of us should try to use the powers of reason to seek the truth according to our own lights, free from the burden of preconceived opinion or received doctrine. This is a noble ideal, which defines much that is precious in the emergence of modern Western culture. Second, and flowing from this, we have the Enlightenment ideal of autonomy. This also deserves to be respected, in so far as it upholds the significance of individual choice, free from external bullying and the internal tyranny of irrational emotion. So despite the current fashionable denigration of modernity and the Enlightenment, its core values of individuality and independence still have much to teach us. But, third, that exalting of the individual carries serious risks, if it degenerates into the Nietzschean fantasy that anyone can create value for themselves by an act of individual choice. Individual choice is valuable only if it is directed to an object that is independently good.

But how do we decide what is independently and objectively good? Descartes was a sincere religious believer, a devout Catholic, who never doubted that his individual reason was illuminated by the eternal divine source of truth and goodness, whose spark was innate in all of us. Whether such resonant, theistically-based objectivism is tenable is far too big a topic to embark on here. Suffice it to say that the so-called post-modernist climate of our own age is highly suspicious of grand claims of ethical objectivity, preferring instead to stress the contingency of various forms of local discourse, each with its own criteria for value. But that seems to leave us in a kind of limbo - a fluctuating ebbing and flowing of different competing currents, with nothing to rescue the individual from being carried away by whatever eddy or flow happens to drag him about from moment to moment.