Look around you right now. You’re surrounded by things that exist, like your tea mug, your chair, and the walls around you. But, according to many philosophers, you are also surrounded by innumerable things that don’t exist, like omissions, absences, holes, and negative properties. For example, in your crumpet are tiny holes—tiny “lacks” of crumpet. There is neither a big purple monster sitting behind you nor a rain cloud contained in your tea mug: both are absences, if strange ones. And almost everything in your world has some negative properties. For example, your kidney has the negative property not a hat, and you have the negative property not the number four.

     Non-Being: New Essays on the Metaphysics of Non-existence, edited by Tyron Goldschmidt and me,brings together 17 new philosophical papers on the topic of non-existence. Specifically, the volume addresses the metaphysics of nonexistence. In philosophy, metaphysics is the study of fundamental reality. Metaphysics is different than epistemology, which addresses what we can know, and different from ethics, which addresses what is right and wrong.

     My own paper, “Ontological Pluralism about Non-Being”, begins the volume. We can begin by breaking down the title. The “ontological” means that the view set forth in the paper is about what exists, a topic philosophers call ontology. (Note that this is different from oncology, the medical study of cancer.) The “pluralism” indicates multiple forms of something—in this case, multiple forms of non-being.

     In order to understand the philosophical view set forth in the paper, first consider that there might be totally different ways of existing. For example, the number seven is totally unlike a blanket. One can never be the other, no matter how much each one changes. These differences between types of things lead some philosophers to posit ontological pluralism, the view that there are multiple fundamental ways of being that are very different from each other. Ontological pluralists come in a variety of philosophical flavors. Some believe in fundamental differences between the mind and the body. Some believe in fundamental differences between concrete objects, like chairs, and abstract objects, like numbers. Some believe in fundamental differences between God and everything else. And so on. There are many applications of the view, which has become trendy in academic philosophy in the past 15 years or so. (Yes, academic philosophy has trends, just like everything else!)

     My paper explores the idea that there are several ways of non-being, just as there might be several ways of being. On the surface, this idea might seem very strange: non-existence doesn’t seem like it has a sort of character, let alone the sort of character that permits distinctions. If the iPod 59 doesn’t exist and manned lunar colony don’t exist, it seems like they don’t exist in exactly the same way.

     But some kinds of nonexistent things do seem to differ from each other. For example, consider omissions, events that are close to happening but don’t happen. Suppose that you narrowly avoid striking a deer with your car on the way to work. Hitting the deer very well could have happened, but it did not. Now imagine events that aren’t even close to happening, like a mathematician proving that 2+2 = 5. These absences seem different than the sorts of events that were close to happening, like you hitting the deer. Ontological pluralism about non-being can account for the difference between omissions and absences, for it says that these two sorts of non-being are fundamentally unalike, just as numbers and chairs are fundamentally unalike.

     The view has another application in accounting for differences between past and future times. To see why, let’s take a brief foray into the metaphysics of time. One central question in the metaphysics of time is which times exist: if one were to have a bird’s eye-view of reality, exactly what would one see? Philosophers give a few different, and competing, answers. One answer, eternalism, holds that all times exist. According to this view, time is a lot like space: all times are in some sense “out there” in a four-dimensional diorama, perennially existing. From a bird’s-eye view of an eternalist universe, one would see past events, like the existence of dinosaurs; present events, like your reading this article; and future events, like manned Mars colonies. Another answer, presentism, holds that only the present moment exists. From a bird’s-eye view, one would just see a minimal slice of reality. And an intermediate theory, growing block, holds that the past and present are real, and existence expands at every moment with the passage of time.

     One problem for presentists and eternalists is how to explain the apparent differences between the past and the future. The past seems fixed while the future seems open. Moreover, events seem ordered in a particular way. For example, your alarm clock sounded, which caused you to wake up. But reversing these events would not make causal sense: waking up doesn’t cause your alarm to sound. We cannot just rearrange events like a card deck and maintain the causal coherence of the world. Causation orders events in such a way that they run from past to future. Causes are in the past; effects are in the future.

     What does this have to do with pluralism about non-being? The pluralist about non-being can hold that past and future times are fundamentally different sorts of things. The past is fixed and changeless; the future is open. This view is particularly appealing to presentists, who (recall) hold that only the present moment exists. Since past and future moments don’t exist, presentists have traditionally had a hard time maintaining any sort of metaphysical difference between the past and the future. But the pluralist about non-being can hold that non-existent past times and non-existent future times are fundamentally different sorts of things.

     This is just one chapter out of seventeen chapters in the volume. The metaphysics of non-being is a surprisingly rich topic: the papers in the volume span many different perspectives and areas of focus. There is a chapter on what, exactly, constitutes a hole in a ballot, an issue that plagued the 2000 United States presidential election. There is a chapter on the moral status of omissions versus actions, and the differences between the two. There is a paper on whether death—what some consider the ultimate form of non-being—is harmful to a person. There is a paper on the Buddhist conception of non-being. And there is a paper on the old riddle of Thales, whether day or night is older.

     Nothingness, it turns out, isn’t nothing. If you’re interested in taking a deep dive into the void, pick up a copy of Non-Being: New Essays on the Metaphysics of Nonexistence from Oxford University Press.

Sara Bernstein is Associate Professor of Philosophy at the University of Notre Dame in Indiana, USA. She teaches and writes mainly in metaphysics, including ontology, causation, time, space, and time travel. She has held the Thomas J. and Robert T. Rolfs Professorship at the University of Notre Dame, the Philip L. Quinn Fellowship at the National Humanities Center, the Andrew W. Mellon Assistant Professorship at Duke University, and has been a visitor at Arché at the University of St. Andrews, the Australian National University, and the University of Milan. Prior to her current position, she was assistant professor of philosophy at Duke University.

You can buy Non-Being: New Essays on the Metaphysics of Nonexistence here: https://oxford.universitypressscholarship.com/view/10.1093/oso/9780198846222.001.0001/oso-9780198846222