Metaphysics << `meht` uh FIHZ ihks >> is the branch of philosophy concerned with the basic nature of reality. Its aim is to give a systematic account of the world and the principles that govern it. In contrast to the natural sciences, which study specific features of the world, metaphysics is a more general investigation into the fundamental features of what exists. The metaphysician relies on forms of analysis that depend on pure reason rather than the experimental methods of the natural scientist. Metaphysical speculation has always focused on certain key concepts such as space and time, causality, identity and change, possibility and necessity, universals and particulars, and mind and body.
Space and time.
When philosophers want to understand the nature of the universe, they often begin by examining the nature of space and time. Such questions as “Can there be time without change?” and “Is space something distinct from the objects in the universe?” belong to the realm of metaphysics. Some metaphysicians have argued that space and time are absolute–that is, independent of any change in the arrangement of the contents of the universe. But according to the relativistic account, both space and time can be reduced to the relationships between things in the universe.
Causality.
Theories of causality attempt to answer questions about how or why events happen. The concept of causality is closely related to problems of determinism and free will. Determinism states that strict causal laws govern all events, even human actions. Nondeterministic metaphysical theories claim that events are not controlled by external causes. These theories state that people freely choose their own actions, and in any situation could choose otherwise than they actually do.
Identity and change.
Studying the relationship between identity and change helps philosophers understand how things can persist through time even though they seem to change. Most people will agree that objects can change without becoming different things. For example, a coat of paint will not transform a house into a different house. However, it is unclear to what extent changes can take place without destroying the original object. Thus, if we gradually replace all the parts of a house, it seems that we will have slowly destroyed the old house and built a new one in its place. Some metaphysical theories distinguish an object’s form, or organization, from the matter out of which it is made. They argue that the form persists through time and guarantees the identity of the object through changes.
Possibility and necessity.
When philosophers want to know how people make judgments of truth, they often examine the concepts of possibility and necessity. These questions are related to issues of necessary truths and contingent truths. That there are 9 planets in our solar system is a contingent truth, because there could be 10 planets or even no planets. On the other hand, the fact that 2 + 2 = 4 is a necessary truth, because it could not be otherwise. Once philosophers have distinguished between possibility and necessity, they can consider whether there are essential properties of objects. If it is a necessary truth that a thing have a certain property, philosophers call that property an essential property. Thus, warm-bloodedness is presumably an essential property of dogs, and brownness is only an accidental (nonessential) property of some dogs.
Universals and particulars.
Thinking about the nature of objects and their properties often leads philosophers to discussions of universals and particulars. A universal is something that many separate things have in common. A particular is an object with many properties. For example, the property of redness is common to many individuals. Some metaphysicians believe there is therefore a universal redness. Realism about universals is the doctrine that universals can exist separately from particulars and that there is a universal redness common to all red things. Thus, in a realistic theory, universal redness is something more than the totality of all red things. In contrast, nominalistic theories claim that there is no universal redness and that red is simply a word that people apply to all red things in the world.
Mind and body.
Many metaphysical problems arise from the observation that mind and body seem to interact, even though they appear to have nothing in common. These problems can be phrased in such questions as “Is the mind a physical thing?” and “Are people’s minds identical with their brains?” Dualism contends that mind and matter are two fundamentally distinct kinds of things. A basic problem for dualism is to explain how a physical process can have a nonphysical effect, or how mental events can result in changes in the physical world. Monism denies that mind and matter are two different things. Monism can be either materialistic, asserting that only matter exists, or idealistic, claiming that mind is basic to everything.
Opinions about metaphysics.
The apparent failure to reach widespread agreement on metaphysical issues has prompted some philosophers to insist that these questions are beyond the power of human beings to answer. In the early 1900’s, philosophers who called themselves logical positivists argued that metaphysical questions were meaningless because no amount of evi-dence could possibly decide them one way or another.
The positivists’ critique of metaphysics was widely accepted in the 1920’s and 1930’s, but most philosophers today are less inclined to dismiss metaphysical theories. There are no easy answers to metaphysical questions. But philosophers now believe that they can judge these theories by how well they satisfy people’s basic intuitions, and combine with accepted scientific theories to provide a unified view of the world.
