Twenty-one years have passed between the two main parts of this book, ‘Observation’ and ‘Speculation’: the gaze on what there is and the attempt to reflect on the conditions of possibility of what there is. So what unites them, you might ask, if not the rather loose thread of the author's identity? Rest assured, there is more; or at least I hope you will think so after reading. But before I leave you to it, I would like to say a couple of words that may make things easier to follow.

At the end of the twentieth century, when I wrote ‘Observation’ (which came out in Italian in 2001 under the title Il mondo esterno (The External World), my concern was to relaunch realism – or more precisely the critical force of the real – in a context where both analytic and continental philosophers seemed persuaded that reality was not a matter for philosophy, which was supposed to deal either with reasoning (for the analytics) or ideology (for the continentals). Both kinds of philosophers were living under the weight of the Kantian saying ‘intuitions without concepts are blind’; therefore, to be a philosopher means to deal with concepts, whether to analyse them (as analytics did) or deconstruct them (as continentals did). Thus, both sides forgot about the other side of Kant's saying: namely that concepts without intuitions are empty. Above all, they both overlooked the fact that intuitions often tend to disprove concepts, expectations and rules.

The notion of ‘Unamendability’, which lies at the heart of ‘Observation’, underlines precisely this point. Intuitions may be blind, but most of the time they are more than sufficient for our being in the world, with or without concepts. I do not need to know Newton's laws to ride a bike, and I do not need to have read Keynes to use money. This is demonstrated not only by the most banal observation of human life, but also by the fact that if concepts played any constitutive role in the construction of reality, then they would be able to change reality, too: not just in the epistemological sense of what we know or believe we know, but in the ontological sense of what there is.