Metaphysics

I

Introduction

Metaphysics, branch of philosophy concerned with the nature of ultimate reality. Metaphysics is customarily divided into ontology, which deals with the question of how many fundamentally distinct sorts of entities compose the universe, and metaphysics proper, which is concerned with describing the most general traits of reality. Together, these general traits define reality and would presumably characterize any universe. Because these traits are not peculiar to this universe, but are common to all possible universes, metaphysics may be conducted at the highest level of abstraction. Ontology, by contrast, because it investigates the ultimate divisions within this universe, is more closely related to the physical world of human experience.

The term “metaphysics” is believed to have originated in Rome about 70 bc, with the Greek Peripatetic philosopher Andronicus of Rhodes (fl. 1st century bc) in his edition of the works of Aristotle. In the arrangement of Aristotle’s works by Andronicus, the treatise originally called First Philosophy, or Theology, followed the treatise Physics. Hence, the First Philosophy came to be known as meta (ta) physica, or “following (the) Physics”, later shortened to Metaphysics. The word took on the connotation, in popular usage, of matters transcending material reality. In the philosophical sense, however, particularly as opposed to the use of the word by occultists, metaphysics applies to all reality and is distinguished from other forms of inquiry into reality only by its generality.

The subjects treated in Aristotle’s Metaphysics (substance, causality, the nature of being, and the existence of God) fixed the content of metaphysical speculation for centuries. Among the medieval scholastic philosophers, metaphysics was known as the “transphysical science” on the assumption that, by means of it, the scholar could make the transition philosophically from the physical world to a world beyond sense perception. The 13th-century scholastic philosopher and theologian St Thomas Aquinas declared that the cognition of God, through a causal study of finite sensible beings, was the aim of metaphysics. With the rise of scientific study in the 16th century the reconciliation of science and faith in God became an increasingly important problem.

II

Metaphysics Before Kant

Before the time of the German philosopher Immanuel Kant, metaphysics was characterized by a tendency to construct theories on the basis of a priori knowledge, that is, knowledge derived from reason alone, in contradistinction to a posteriori knowledge, which is gained from experience. From a priori knowledge were deduced general propositions that were held to be true of all things. The method of inquiry based on a priori principles is known as rationalistic. The metaphysical theories that were developed using this method may be divided into monism, which holds that the universe is made up of a single fundamental substance; dualism, the belief in two such substances; and pluralism, which proposes the existence of many fundamental substances.

The schools of monism, while agreeing that only one basic substance exists, differ in their descriptions of its principal characteristics. Thus, in idealistic monism the substance is believed to be purely mental; in materialistic monism it is held to be purely material, and in neutral monism it is considered neither exclusively mental nor solely material. The idealistic position was held by the Irish philosopher George Berkeley, the materialistic by the English philosopher Thomas Hobbes, and the neutral by the Dutch philosopher Baruch Spinoza. The latter expounded a pantheistic view of reality in which the universe is identical with God and everything is an expression of God’s substance.

The most famous exponent of dualism was the French philosopher René Descartes, who maintained that body and mind are radically different entities and that they are the only fundamental substances in the universe. Dualism, however, does not show how these basic entities are connected.

In the work of the German philosopher Gottfried Wilhelm Leibniz, the universe is held to consist of an infinite number of distinct substances, or monads. This view is pluralistic in the sense that it proposes the existence of many separate entities, but it is monistic in its assertion that each monad reflects within itself the entire universe.

Other philosophers have held that knowledge of reality is not derived from a priori principles, but is obtained only from experience. This view of knowledge is called empiricism. Still another school of philosophy has maintained that, although an ultimate reality does exist, it is altogether inaccessible to human knowledge, which is necessarily subjective because it is confined to states of mind. Knowledge is therefore not a representation of external reality, but merely a reflection of human perceptions. This view is known as scepticism, or, in respect to the soul and the reality of God, agnosticism.

III

The Metaphysics of Kant

Several major viewpoints were combined in the work of Kant, who developed a distinctive critical philosophy called transcendental idealism. His philosophy is sceptical in that it denies the possibility of a strict knowledge of ultimate reality; it is empiricist in that it affirms that all knowledge arises from experience and is true of objects of actual and possible experience; and it is rationalistic in that it maintains that it is possible to have a priori knowledge of the structural principles of this empirical knowledge.

These principles are held to be necessary and universal in their application to experience, for in Kant’s view the mind by its nature furnishes the archetypal forms and categories (space, time, causality, substance, and relation) to its sensations. These categories are logically prior to and necessary for experience, although manifested only in experience. Their logical priority to experience makes these categories or structural principles transcendental; they transcend all particular experiences, both actual and possible. Although these principles determine all experience, they do not in any way affect the nature of things in themselves, that is, things as they are independent of being experienced by people. The empirical knowledge that is structured by these principles must not be considered, therefore, as providing a revelation of things as they are in themselves. This knowledge concerns things only insofar as they appear to human perception or as they can be apprehended by the senses. For Kant, the description of the system of categories and structural principles governing experience is itself a metaphysics, but it is a metaphysics of reality as it is for human beings, that is, a metaphysics of the only reality that can ever be known, rather than of reality as it is in itself.

The argument by which Kant sought to fix the limits of human knowledge within the framework of experience and to demonstrate the inability of the human mind to penetrate beyond experience strictly by reason to the realm of ultimate reality constitutes the critical feature of his philosophy, expounded in Critique of Pure Reason, Critique of Practical Reason, and Critique of Judgement. In the system propounded in these works, Kant also sought to reconcile science and religion in a world of two levels, comprising “noumena”, objects conceived by reason although not perceived by the senses, and “phenomena”, things as they appear to the senses that are accessible to material study. He maintained that, because God, freedom, and human immortality are noumenal realities, these concepts are understood through moral faith rather than through scientific knowledge.

IV

Metaphysics Since Kant

Some of Kant’s most distinguished successors, notably Johann Gottlieb Fichte, Friedrich Schelling, G. W. F. Hegel, and Friedrich Schleiermacher, negated Kant’s criticism in their elaborations of his transcendental metaphysics by denying the Kantian conception of the thing-in-itself. They thus developed an absolute idealism in opposition to Kant’s critical transcendental idealism.

Since the formation of the hypothesis of absolute idealism, the development of metaphysics has resulted in as many types of metaphysical theory as existed in pre-Kantian philosophy, despite Kant’s contention that he had definitely fixed the limits of philosophical speculation. Notable among these later metaphysical theories are radical empiricism, or pragmatism, a native American form of metaphysics expounded by Charles Sanders Peirce, developed by William James, and adapted as instrumentalism by John Dewey; voluntarism, the foremost exponents of which are the German philosopher Arthur Schopenhauer and the American philosopher Josiah Royce; phenomenalism, as it is exemplified in the writings of the French philosopher Auguste Comte and the British philosopher Herbert Spencer; emergent evolution, or creative evolution, originated by the French philosopher Henri Bergson; and the philosophy of the organism, elaborated by the British mathematician and philosopher Alfred North Whitehead. The salient doctrines of pragmatism are that the chief function of thought is to guide action, that the meaning of concepts is to be sought in their practical applications, and that truth should be tested by the practical effects of belief; according to instrumentalism, ideas are instruments of action, and their truth is determined by their role in human experience. In the theory of voluntarism the will is postulated as the supreme manifestation of reality. The exponents of phenomenalism, who are sometimes called positivists, contend that everything can be analysed in terms of actual or possible occurrences, or phenomena, and that anything that cannot be analysed in this manner cannot be understood. In emergent or creative evolution, the evolutionary process is characterized as spontaneous and unpredictable rather than mechanistically determined. The philosophy of the organism combines an evolutionary stress on constant process with a metaphysical theory of God, the eternal objects, and creativity.