Andrea Bottani Massimiliano Carrara Pierdaniele Giaretta What do we do when we do metaphysics? The aim of this introduction is to give a provisional answer to this question, and then to explain the subtitle of the volume. It is easy to observe that when we do meta­ physics we engage in a linguistic activity, mainly consisting of uttering declarative sentences that are not very clear to most people. That is true, but, of course, it is not very informative. What do we speak of when we do metaphysics? A traditional answer could be: we speak of what things really are, so suggesting that things can appear in a way that is different from the way they really are. So understood, meta­ physics is about the sense, or the senses, of "real being". A question that immediately arises is whether the sense of being is unique or is different for different types of things. Another question is whether it is possible that something could appear to be, but really not be. Modem analytic metaphysicians usually answer that the sense of being is unique, while acknowledging that there are different kinds of things, and that to say that something could appear to be but really not be is a plain contradiction, unless what is understood is that it could appear to us that there is something having such and such features, but viii Individuals, Essence, and Identity really there is no such a thing.