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Introduction

Metaphysics, or first philosophy, is that branch of philosophy concerned with the nature of reality in its most fundamental aspects: existence, the part/whole relation, space, time, causality, possibility and necessity, similarity and dissimilarity. It includes ontology, the study of what exists, as well as the investigation of the most general features of reality. Metaphysicians seek to understand the real structure and the unity of the world and to catalog the ways in which its parts relate to each other.

In this chapter, we begin with a short history of metaphysics (1.1), followed by a discussion of some reasons why metaphysics matters (1.2). We conclude with some guidance about how best to use this book (1.3).

1.1 A Brief History of Metaphysics

Metaphysics is the oldest branch of philosophy. The early, pre-Socratic philosophers of Ionia (off the coast of Turkey) and southern Italy proposed theories about the universal nature of things and about change and the explanations of change. Many of the early philosophers, including Empedocles (c. 490-430 BC) and Democritus (c. 460-370 BC), approached these questions from a materialistic point of view, assuming that wisdom comes primarily from understanding what things are made of. In the fourth century BC, the great Greek philosopher Plato (428/427 or 424/423-348/347 BC) developed a theory of "forms" as a deep explanation for what makes things of a kind similar to each other, as an alternative to the earlier materialism. Plato's student, Aristotle (384-322 BC), built upon the work of all of his predecessors in creating the first comprehensive and systematic metaphysical theory in a work that acquired (for the first time) the title Metaphysics. Aristotle describes his subject as "primary" or "first" philosophy and as the study of being as such. Aristotle examined the nature of change and of powers to change, and he built a theory of categories to use in classifying all of the constituents of reality. Like Plato, Aristotle rejected simple materialism and emphasized the qualitative and holistic features of the world, especially of living organisms.

Both Plato and Aristotle founded schools of philosophy, and their students and their students' students extended their philosophical work over many generations. During the Hellenistic period (between the conquests of Alexander and the rise of Rome), three additional major schools of philosophy appeared-the Stoics, the Epicureans, and the Skeptics. Both the Stoics and Epicureans revived a more materialistic approach to understanding life and human action. During the Hellenistic and Roman periods, such metaphysical investigations continued, but gradually attention turned to ethics, politics, and the theory of knowledge (epistemology). The problem of defending the very possibility of knowledge against the challenge of the Skeptics became a major preoccupation, and Plato's Academy began to defend (at least in public) a moderate form of skepticism.

In Late Antiquity and the Middle Ages, philosophical work in the Mediterranean basin and in Europe fell predominantly into the hands of Christians, Jews, and Muslims, and during this period philosophers returned to metaphysics as their central focus. Aristotle's influence grew, as more of his work was translated and commented upon in both Arabic and Latin. The resulting philosophical movement, known as 'scholasticism', achieved the status of being the consensus view for many hundreds of years.

This consensus began to dissolve in the seventeenth and eighteenth centuries, as a result of the success of modern science, which returned in important respects to the materialism of Democritus and the Epicureans. At the same time, the French philosopher René Descartes (1596-1650) re-introduced a fixation on the problem of refuting the skeptics. Descartes recommended answering the skeptics by turning inward, building the foundations of science and philosophy firmly upon the indubitable contents of one's own mind and experience. This inward or subjective turn profoundly affected the course of metaphysics for hundreds of years, leading to the dominance of various forms of idealism, according to which all of reality is fundamentally mental or experiential in character.

In the early twentieth century, a number of philosophers began turning away from idealism and from any attempt to build an indubitable foundation for knowledge that would be immune to the challenge of the skeptic. The British philosopher G.E. Moore (1873-1958) argued that our ordinary knowledge of the world is rationally more secure than any skeptical challenge. Ludwig Wittgenstein (1889-1951), an Austrian who made his career in England, pointed out that doubt stands in no less need of justification than does belief. Wittgenstein concluded that skeptical doubts lacked adequate justification. Many philosophers, in Britain, the United States, and continental Europe, argued that science requires no foundation other than that provided by ordinary observations, which embody knowledge about our physical environment. Thus, philosophy began to turn outward again, in a way that supported the revival of more traditional approaches to metaphysics-materialistic, Platonic, and Aristotelian or scholastic.

For a brief period at the end of the nineteenth century and beginning of the twentieth century, metaphysics fell out of favor among philosophers. Some (such as Friedrich Nietzsche (1844-1900), Karl Marx (1818-1883), William James (1842-1910), and Søren Kierkegaard (1813-1855)), because of theories in psychology and cultural studies, raised doubts about the ability of the metaphysician to escape the prejudices and interests of one's class and time or the idiosyncratic influence of one's personal constitution. Others (such as those in the Vienna Circle and Ludwig Wittgenstein) embraced an extreme empiricism, arguing that all meaningful assertions must be directly verifiable or falsifiable by the senses, a standard which relegated metaphysical theory to the category of the nonsensical. Yet another group limited the task of the philosopher to analyzing the underlying grammar and logic of ordinary language.

But the middle of the twentieth century witnessed one of the most remarkable rebirths in Western philosophy: a dramatic renaissance of interest in pure metaphysical theory. The impetus for this revival came in part from circles that had once been hostile to the metaphysical enterprise and in part from philosophers working within older traditions that had survived despite that hostility. Some philosophers of physics found themselves inquiring into the structure of space, time, and causation in ways that revived ancient debates. Some who had studied the logical structure of ordinary language found that they could not avoid questions about ontology-questions about which sorts of things really exist. Others returned to the Aristotelian and scholastic traditions that had survived. Significant circles of metaphysical research began in the 1940s in Australia, at Oxford and Cambridge, and at Harvard. Logical research that had dominated philosophy in the early twentieth century matured naturally into metaphysical investigations into the nature of possibility and necessity and of time. By the early twenty-first century, metaphysics had reclaimed its place at the very center of philosophy.

1.2 Why Do Metaphysics?

The practice of metaphysics is controversial within philosophy itself. This controversy stems from two primary sources: skepticism and pragmatism. Anti-metaphysical skeptics question whether it is possible to reach knowledge or even reasonable opinion about metaphysical questions. Our response to the skeptic is simply that the proof is in the pudding. The best rebuttal of those who claim that metaphysics is impossible is simply to do it.

The pragmatic challenge to metaphysics is perhaps even more widespread. Even if metaphysics is possible, the pragmatist asks, why is it important? There are many more urgent philosophical questions, questions about ethics and politics (the good and the right), and questions of epistemology (what do we know, and how do we know it?).

Our response to the pragmatist is twofold. First, we would argue, with Aristotle, that philosophy begins with a sense of wonder and curiosity about the world, a wonder and a curiosity that inevitably led to puzzling over the metaphysical questions: what sorts of things really exist, and how do these things relate to one another? Much of what we do in science and scholarship generally is motivated by pure curiosity about our selves and our world. Not everything can be evaluated in terms of cash value.

Second, metaphysical questions are relevant to other questions, both in value theory and in epistemology and philosophy of science, as we will argue in this chapter. Even when philosophy is primarily engaged in ethical or epistemological reflection, the issues of metaphysics cannot be avoided.

1.2.1 Fatalism and alternative possibilities

The making of decisions is a characteristic feature of human life. Much of our time is consumed in considering and deliberating about what to do, and our emotions are much engaged with questions of the correctness of our past, present, and future choices. The practice of making choices seems to presuppose that the future could take any one of many alternative courses, and that which course it takes is to some extent up to each of us. This...