Metaphysics, History of

views updated


The word metaphysics derives from the Greek meta ta physika (literally, "after the things of nature"), an expression used by Hellenistic and later commentators to refer to Aristotle's untitled group of texts that we still call the Metaphysics. Aristotle himself called the subject of these texts first philosophy, theology, or sometimes wisdom; the phrase ta meta ta physika biblia ("the books after the books on nature") is not used by Aristotle himself and was apparently introduced by the editors (traditionally by Andronicus of Rhodes in the first century BCE) who classified and cataloged his works. Later, classical and medieval philosophers took this title to mean that the subjects discussed in the Metaphysics came "after the things of nature" because they were further removed from sense perception and, therefore, more difficult to understand; they used Aristotle's frequent contrast of things "prior and better known to us" with things "prior and better known in themselves" to explain why the treatises on first philosophy should come "after the books on physics." In medieval and modern philosophy "metaphysics" has also been taken to mean the study of things transcending naturethat is, existing separately from nature and having more intrinsic reality and value than the things of naturegiving meta a philosophical meaning it did not have in classical Greek.

Especially since Immanuel Kant metaphysics has often meant a priori speculation on questions that cannot be answered by scientific observation and experiment. Popularly, "metaphysics" has meant anything abstruse and highly theoreticala common eighteenth-century usage illustrated by David Hume's occasional use of metaphysical to mean "excessively subtle." The term has also been popularly associated with the spiritual, the religious, and even the occult. In modern philosophical usage metaphysics refers generally to the field of philosophy dealing with questions about the kinds of things there are and their modes of being. Its subject matter includes the concepts of existence, thing, property, event; the distinctions between particulars and universals, individuals and classes; the nature of relations, change, causation; and the nature of mind, matter, space, and time. In the eighteenth and nineteenth centuries metaphysics was used broadly to include questions about the reality of the external world, the existence of other minds, the possibility of a priori knowledge, and the nature of sensation, memory, abstraction, and so on. In present usage these questions are included in the study of epistemology.

The Classical Period

The history of metaphysics in Western philosophy (taking "metaphysics" in the contemporary sense) began with speculations by the Ionian cosmologists in the sixth century BCE about the origin of the physical universe, the matter or stuff from which it is made, and the laws or uniformities everywhere present in nature. Our knowledge of these early cosmologists comes mostly from Aristotle and other classical authors; the main figures were the Milesians (Thales, Anaximander, and Anaximenes), Pythagoras, and Heraclitus.


The beginning of metaphysics, however, is most conveniently dated from Parmenides (fl. c. 475 BCE), since some of the typical characteristics of metaphysics as a distinct philosophical inquiry are present in, or at least suggested by, his surviving writings. These characteristics are, first, the conception of philosophy as an attempt to understand the universe by means of a logical investigation that is a priori, appealing to meanings of terms rather than to the evidence of the senses. This method is in contrast to the method of natural science, which relies on sense perception. Second is a more or less explicit use of very general principles viewed as sufficient to arrive at a true account of reality. Such principles were, for example, noncontradiction and something like a principle of sufficient reason, which is expressed in Parmenides' poem: "Also, what necessity impelled it, if it did spring from Nothing, to be produced later or earlier? Thus it must Be absolutely, or not at all." Philosophy was therefore conceived as a deductive science like mathematics. Third is the paradoxical contrast between apparent reality and true reality and the association of the truly real with singleness and unchangingness.

Of these features of Parmenides' writings, the first is fundamental; it can be taken as a defining characteristic of metaphysics. Like the natural scientist, the metaphysician gives an account of the universe; unlike the scientist, he does not base his account on observations and experiments, at least not on any special observations and experiments made for the purpose. His account is based primarily on analysis of concepts; if he does appeal to the evidence of the senses, he appeals to something generally familiar, not to new evidence he is adding to knowledge. Parmenides himself apparently believed he had done all that could be done by way of a philosophical account of the universe. His account consists in pointing to what he believed were the logical consequences of saying "It is." He dismissed everything else either as poetic imagery with no claim to truth or as empirical science; he indiscriminately referred to both as opinion. His position was not naive; it is not easy to see how a metaphysician can give an account of reality based on logic alone unless reality in some sense has the features of necessity and vacuous generality belonging to logical truths. And doctrines similar to Parmenides' logical monism have frequently reappeared in the history of metaphysicsfor example, in Neoplatonism, in Benedict de Spinoza, and in nineteenth-century Hegelianism. There is more than a superficial resemblance between Parmenides' Being, the Neoplatonists' One, Spinoza's God or nature, and G. W. F. Hegel's Absolute as understood by a metaphysician like F. H. Bradley. Perhaps the underlying reasoning is that recognizing that metaphysics gives an account of the world based on analysis of concepts rather than on empirical evidence, these philosophers have felt that logic alone should be sufficient basis for making assertions about the world; since whatever is logically true is thought to be necessarily and always true, they have concluded that the world itself must be unchanging and in some sense necessarily what it is.

later pre-socratics

Parmenides apparently believed he had said all that a metaphysician could say about the world. Accordingly, his followers Melissus and especially Zeno are more critical than constructivea trait shown by many later metaphysicians who are more often concerned to demonstrate what they take to be logical failures in the ordinary or scientific understanding of reality than to give a positive account of reality. We learn from Plato's Parmenides that Zeno's paradoxes of motion were meant to support Parmenides' system by showing contradictions in the ordinary concept of change. (When does the arrow move? Not now, because at any given instant it is in one place and hence not moving; not at some other time, because if it is moving, it must be moving now.)

Parmenides' general effect, however, was to interest philosophers in following what seemed to be the logical implications of their assumptions. An example is Anaxagoras, who apparently argued from the assumption that reality is many and changing to the conclusion that the things we ordinarily call real are composed of unendingly smaller parts similar to the whole things, that "all things are together," that "everything contains a part of every other thing," and that although there are rearrangements of things, nothing is ever really created or destroyed. Like his contemporaries Empedocles and the atomists Leucippus and Democritus, Anaxagoras did rely on observation and experiments to give an account of nature, but the surviving fragments suggest that his cosmology was arrived at largely by a priori reasoning in the way Parmenides' was, although the resulting account of reality is the opposite of Parmenides' account. And in the same way that something like Parmenides' logical monism is repeated in Neoplatonism, in Spinoza, and in nineteenth-century Hegelianism, something like Anaxagoras's logical pluralism is repeated in Gottfried Wilhelm Leibniz's theory of monads and Bertrand Russell's logical atomism. The common feature of this kind of system is that on logical grounds reality is described as composed of elements viewed as the limit of an unending process of division; the least parts of things are, so to speak, real infinitesimalsthings smaller or simpler than any given thing one can mention. The atomism of Leucippus, Democritus, and, later, Lucretius is, by contrast, primarily a physical theory. These thinkers believed that the existence of atoms can be shown empirically; their atoms have finite sizes and such recognizable physical properties as shape and motion and, perhaps, weight, and the theory anticipates Galileo Galilei and Isaac Newton rather than Leibniz and Russell.


In Plato's Phaedo Socrates is made to say he once studied Anaxagoras but gave up this study and all empirical investigations of nature, deciding instead to "have recourse to conceptions and examine in them the truth of realities." Anaxagoras, Parmenides, and others had also had recourse to conceptions in contrast to the evidence of the senses; what is new in the Phaedo is the theory of Ideas or Forms, which historians of philosophy sometimes ascribe to Plato (c. 427347 BCE) and sometimes to Socrates himself. For Plato, at least, ideas exist independently of the things we see and touch; moreover, they are considered the source of existence of things we see and touch, somewhat as a man is the cause of his shadow or of his reflection in a mirror or a pool of water. Popularly, Plato's metaphysics means the theory of Ideas in this sense, and in this way the theory has had a great influence in the history of thought. Plato's own evaluation, however, was considerably more critical than that of many of his followers. The theory of Ideas in this form is presented in the Phaedo as a hypothesis that cannot be known to be true; in the Parmenides its logical weaknesses are pointed out; in the Timaeus it is used as part of a "probable" or "likely" cosmology. Nevertheless, Plato does consistently argue for the existence of mind or soul as a kind of entity distinct from, and in some sense prior to, physical objects. This thesis is developed, notably in the Phaedo, where the theory of Ideas is used as a step in proving the immortality of soul, in the Phaedrus, and in Book X of the Laws. In these contexts Plato argues that since bodies cannot move themselves (apparent self-motion is reduced to one part's moving another) whereas soul can, the ultimate source of observed motions must be soul or mind. In the Laws this argument is used to prove the existence of the gods, who are understood as sources of observed motions and changes in the visible universe.

Plato's technical contributions to metaphysics are contained in the difficult later dialogues, especially the Parmenides and Sophist. Both dialogues purport to be a criticism of Eleatic philosophy, by Parmenides himself in the Parmenides and by an "Eleatic stranger" in the Sophist. In the Parmenides Parmenides is represented as illustrating the method of dialectic by scrutinizing his own hypothesis that "the One exists" and deducing the logical consequences both of asserting and of denying this hypothesis. The point is that what follows depends on how the hypothesis is understoodin particular, on how one understands unity and existence. If, for example, unity is thought to be in no way compatible with plurality, a thing that has unity can hardly have anything else. Thus, it cannot have spatial extension, for it would then have a right and a left, an up and a down. The more straightforward Sophist classifies philosophers into materialists and idealists according to their criteria of reality. A general criterion of reality as power is suggested, and a number of concepts of equal generality with that of being are introduced and discussedsameness, difference, rest, and motion. The apparent paradox in negation is explained by distinguishing absolute nonbeing (A does not exist) from relative nonbeing (A is non-B ) or otherness and by distinguishing the existential is (A exists) from the is of predication (A is characterized by B ). In the Timaeus the generic concepts are used in the mythical account of the construction of the physical universe by a godlike artisan using an ideal pattern as a blueprint.


Aristotle (384322 BCE) is indirectly the source of the term metaphysics ; he is also the source of a systematic list of metaphysical issues, a technical language in which these issues are stated, and a metaphysical system that has had followers down to the present and has proved immensely fruitful. In part, the importance of this system has been in serving as an object of criticism, although this function has been served by Plato as much as by Aristotle and Aristotle himself illustrates Plato's importance as an object of criticism in the history of metaphysics.

The problems of "first philosophy," or metaphysics, listed by Aristotle in books Beta and Kappa of the Metaphysics are partly about metaphysics itself: Does its subject matter include all the basic concepts and assumptions of all the special sciences? Does it include the principles of logic? Is there metaphysical knowledge in contrast to opinion? These questions ask, in effect, whether metaphysics is a superscience proving the assumptions made by the special sciences and also the assumptions it itself useswhether, in short, it is a logically self-contained body of knowledge contrasting with the logically incomplete special sciences. This concept of metaphysics was held, for example, by René Descartes, but on the whole Aristotle rejected this view. Metaphysics is less the capstone of a hierarchy of sciences than a discussion of problems left over by the special sciences. Physics, for example, assumes there is motion, but it is not part of the metaphysician's job as Aristotle saw it to prove this assumption; at most, he should explain it or defend it from criticism. Aristotle thought of metaphysics as explaining things we already know to be true rather than as giving reasons for the assumptions we make in the sciences and everyday life, thereby providing the underpinnings of science and common sense.

Some of the problems of metaphysics listed by Aristotle are questions about the kinds of things there are. In addition to physical objects perceived by the senses, do such abstractions as Plato's Ideas or the mathematician's numbers, points, lines, and so on also exist? Are all existing things particulars, or do universals like man or whiteness exist, too? Do particulars of the same kind have anything in common, and if so, what and how? Are physical objects something more than the material parts that compose them, and if so, what?

For Aristotle, however, the most fundamental questions of metaphysics concerned the concepts of being and unity. Are being and unity properties of things (since everything both is and is one thing), or are they entities or substances of some kind (as Parmenides seemed to have thought)? If being and unity are things in their own right, what kind of things are they? These questions are suggested by Plato's Parmenides and Sophist. Aristotle's answers are his most important contribution to metaphysics. In the Sophist Plato suggested a general definition of being as power but gave little by way of an explicit analysis of this sense of being, which does not correspond to the use of the word in ordinary language. Such an explicit analysis is the center of Aristotle's metaphysics; his contribution can be summarized as the view that although there are many ways in which things are and are one (and there are therefore many senses of being and unity) and although these ways are irreducibly distinct, they nevertheless depend on one basic kind of being. Being is neither an attribute nor a thing and cannot therefore be defined in the ways triangular or horse can be defined. But we can pick out a basic sense of being, illustrated in such statements as, "This is a horse" or "This is a man," and show how the other senses of being depend on it. "Being a horse," "being a man," and, in general, "being an X " in the basic sense of being means to have attributes and therefore to be a subject of thought and discourse without in turn being an attribute of something else; "being a horse" is not, for Aristotle, an attribute of some more basic subject of thought and discourse. Primarily, what there is, is this horse, this man, and so on when we are speaking of an individual; secondarily, what there is, is horse, man, and so on understood as species or kinds of things. Qualities, dates, locations, motions, relations, and the like are attributed to the things that exist in the basic sense; they themselves do not have independent existence and "are" only in a derivative and borrowed sense of being.

Aristotle's analysis of being is the heart of his metaphysics; it is not the whole of it or the part most stressed by his later followers. What is often referred to as Aristotle's metaphysics is his account of the universe. Roughly, it states that there are a large but finite number of things that for the most part (with exceptions such as the sun, the only thing of its kind, and biological "mistakes" resulting from mutation and crossbreeding) belong to definite kindsfor example, plant and animal species. In most cases the individual members of these kinds or classes are born and die, but the classes themselves do not change. Some thingsfor example, the starsexist forever and apart from uniform motions do not change at all. There is an ultimate prime mover that is the source of all observed motion and change but is itself completely immaterial and therefore completely motionless and changeless. This set of ideas is in the Metaphysics, and the pluralism and some theory of natural kinds do follow from Aristotle's analysis of being. But the theory of prime movers and the Unmoved Mover is also in the Physics as a scientificthat is, demonstrableaccount of the physical universe; it is not therefore a true part of his metaphysics, which is dialectical (arguing from common opinion and logic) rather than scientific.

The central chapters of the Metaphysics elucidate and defend the claim that such commonsense things as this horse, this man, and so on are the fundamental subjects of discourse. Aristotle upheld this claim against (1) the view that the ultimate material parts of things are the ultimate subjects of discourse (so that "This is a horse" would be understood as "These material elements have horselike attributes"); (2) the view that Platonic Ideas are the ultimate subject of discourse (where "This is a horse" is understood as "The horse is exemplified by these sensible qualities"); and (3) the view that the basic sense of being is illustrated in, for instance, "There is a horse in the barn"the view according to which "there is" means "it is true that" or "it is a fact that." For Aristotle to be is to be an individual, and the being of a thing is primarily its nature or identifying features rather than the fact that it is. Aristotle hardly even recognized the sense of being involved in such sentences as "There are good men, and there are wicked men," which can be read as "Among all the things that are, some arethat is, have the identifying features ofgood men; others are wicked men." Such sentences suggest that what exists primarily are featureless particulars, which can be referred to collectively as "the things that exist," not commonsense things.

In general, the question "What is being?" became for Aristotle "What is an individual?," a horse, a man, a house, and so on being understood as paradigms of an individual. And, positively, the central argument of the Metaphysics is that an individual is primarily the distinguishing features by which we identify and classify it. Aristotle himself believed that these classifications are learned through experience; he was a realist in the sense that he thought the groups and classes of things are there to be learned by observation and are not simply mental constructions. Therefore, there is a sense in which we learn empirically what being is. But metaphysics is not itself an empirical study of being; Aristotle did not, for instance, think of metaphysics as a science of high-level generality describing the properties that all beings (individuals) have.

Aristotle's Metaphysics in its present formand there is no reason to think it ever had a very different formis barely readable in large stretches. Other parts read like outmoded astronomy; still other parts read like rather tedious lexicography. The devastating criticism of Plato is largely borrowed from Plato himself. However, the Metaphysics gives a surprisingly coherent set of answers to the questions it raises, and the questions themselves are those that metaphysicians still ask.


The Neoplatonists in the late classical period were metaphysicians of great power and originality. They were also of great importance in the development of metaphysics since they formed a link between ancient and medieval philosophy. The main figure of this movement, Plotinus (c. 204270), associated metaphysics with mysticism and personal asceticism. The mystical and religious side of his philosophy was stressed by his disciple and editor Porphyry (c. 232304), and such later Neoplatonists as Iamblichus and Proclus gave a further religious and even occult and superstitious emphasis to the movement. But the intellectual power of the movement is shown in as late a philosopher as Ancius Manlius Severinus Boethius (c. 480524), and through Boethius Neoplatonism had a very strong influence on medieval philosophy and, therefore, indirectly on modern philosophy.


Plotinus's philosophy is a paradigm case of a metaphysical system according to one common conception of metaphysics. It asserts the unreality or half reality of the things of everyday experience; the illusory character of change, motion, and even space and time; the superior reality of soul or mind over matter. It conceives of goodness and intelligence as substantial things and stresses personal mysticism and an ascetic way of life. The line of thought by which Plotinus arrived at this position is not easy to follow, but, briefly, it seems to have been somewhat as follows. Whatever is, is one thing (even a collection of things is said to "be" only when counted as one thinga collection); the answer to the question "What is being?," understood as a request for a description of being, is therefore unity or singleness. But unity or singleness cannot be described any further, although a direct, intuitive experience of it is in some sense possible. Since being is equivalent to unity and since things can have unity to a greater or lesser degree, we can speak of degrees of being. Although unity is itself ineffable, it does duplicate itself in a kind of descending series of thingsin goodness and intelligencein a lesser way in disembodied spirits, in a still lesser way in human souls, least of all in physical objects and their properties and relations. The emanation of successively less real things from unity is to be understood in a logical rather than a physical sense. Speaking accurately, unity or singleness (the One) is not a cause at all, although it can be described metaphorically, for example, as an inexhaustible fountain of being bringing existence to all the things that are by its continuous overflow. Plotinus's writings are full of these metaphors, but he recognized them as metaphors, and the underlying position is rigorously argued, granting the not implausible identification of being with unity or singleness.

Plotinus's line of thought begins with the assumption that being and unity are properties that things haveproperties of utmost generality, to be sure, but still properties in the same way that black or being four-legged are properties of a horse. Combined with this seems to be the Platonic assumption that properties are not simply modifications of particulars or ways that particulars exist; properties are entities in their own right that particular things instance or exemplify. The first of these two assumptions is clearly made in the Isagoge, Porphyry's short introductory treatise on Aristotle's Categories. In Porphyry's accountand in this account he is presumably expressing a typically Neoplatonic point of viewthe theory of categories or types of predication is a theory of kinds of predicates: genus, species, difference, property (that is, essential property), and accident. These kinds of predicates (the predicables) are distinguished from individuals. But even expressions designating individuals are predicates of a sort according to Porphyry; such expressions as "Socrates," "this man here," and "this thing here" are attributes, differing from the predicables because they are "only said of a single thing" whereas the predicables "are said of several things." The distinction is between attributes belonging to several things and attributes belonging to only one thing. But of individuals themselves, in contrast to attributes, nothing is said; they can apparently be characterized only indirectly, as the ultimate subjects of predication.

This account of predication makes the distinction between thing and property peripheral to metaphysics. The important distinction is between relatively less general and relatively more general attributes, culminating in the most general attributes, being and unity. Porphyry spoke of substance as "the most general genus" and in a sense the only real genus, since unlike animal, for example, which is a genus relative to man but only a special case relative to "living thing," substance is not itself a special case of some higher genus. Neoplatonic metaphysics is largely an analysis, similar to Plato's Parmenides, of these ultimate genera; the main force of Plotinus's writings is the argument that the ultimate genera cannot be described in any ordinary way but are in some sense manifest in lower orders of being. Neoplatonism thus easily lends itself to religious interpretation; in the late classical world it actually was a theological system associated with a religious way of life competing with Christianity.

The Middle Ages

Porphyry's Isagoge, translated into Latin by Boethius in the sixth century, gave philosophers some basic tools and stimulated speculation on two questions in particular: (1) What is a thing considered just by itself, as a bare existent, apart from all its attributes? (2) Do attributes exist (or subsist) separately from human thought and discourse and from the things that are said to have attributes? The first question, implicit in Porphyry's account of predication, is roughly the problem of distinguishing essence from existence, what a thing is from the fact that it is. The second question (really, group of questions) was explicitly raised but not answered by Porphyry; it is the problem of universals much discussed throughout medieval philosophy.

For Aristotle the contrast between what a thing is and the fact that it is, is at best peripheral to metaphysics. Aristotle recognized that the question "Does X exist?" is distinct from "What is X ?," but he attached no metaphysical importance to the distinction. Particular questions of the form "Does X exist?" are decided by sense perception or by proof; there is no general metaphysical question about the nature of existence ("thatness") in contrast to essence ("whatness"). The metaphysician is concerned with what things are rather than with their existence or nonexistence. Aristotle's position was that what things arethat is, their beingis primarily what is contained in their definitions; the definition of a thing describes its essence, which is equivalent to its species (the traits that identify it as the kind of thing it is) which is in turn identified with its genus, differentia, and essential properties. But when, as in Porphyry, genus (mammal), difference (solid-hoofed), species (horse), property (neighs), and accident (gray) are indiscriminately called attributes of the thing itself, it is natural to ask what it is that has these attributes or what it is that gives this collection of attributes an actual rather than a merely possible existence.

The problem of universals dominated metaphysics in the early Middle Ages; it was discussed by metaphysicians from Boethius in the sixth century to Roscelin and Peter Abelard in the twelfth century. The main philosophical tradition during this period was the Augustinian tradition, represented by Boethius himself, John Scotus Erigena (c. 810c. 877), St. Anselm (10331109), William of Champeaux (d. c. 1120), St. Bonaventure (c. 12171274), and many others. This tradition favored realism; species and genera like horse and animal were thought to exist not only apart from human thought and discourse (epistemological realism) but also apart from particular horses and animals. Species and genera were regarded as paradigms, archetypes, or exemplars of particular things; as such, they exist in the mind of God and are used by him as models in creating nature. As in St. Augustine and Plato, the fundamental contention is that particulars cannot be recognized and identified as one of a general type unless we first have independent knowledge of the type; the inference is that these general types must exist apart from, and in some sense prior to, the particulars exemplifying them.

St. Anselm's proof of God's existence (anticipated by St. Augustine), has had an important history in its own right; it is also an illuminating example of Christian Platonism in the early Middle Ages. The argument cannot be appreciated apart from its context of religious meditation, but it can be picked out and studied (as it has been by philosophers to this day) as a kind of supreme test case of Platonic (or Neoplatonic) metaphysical assumptions. Briefly, the argument is that (1) we have a concept of a supreme being (a being "than which nothing greater can be conceived") so that (2) the Supreme Being "exists in the understanding." Since (3) it is greater to exist in reality than merely in the understanding, it is contradictory to say the Supreme Being exists only in the understanding; hence, we can infer that (4) the Supreme Being does exist in reality. Kant's objection seems decisive. The existence (as contrasted with the concept of existing) of the Supreme Being cannot be a part of our concept of the Supreme Being. If it were, our concept would be the Supreme Being, not its concept. But the argument seems inevitable if one assumes, as the Neoplatonists did, that existence is an attribute that things have and, in consequence of having it, are, as things are red in consequence of having the attribute redness. Combined with the assumption that attributes have an independent existence, this line of thought leads to the conclusion that existence or being is itself an existing thing; the existence of things in nature is thought of as being due to their receiving a part of the inexhaustible thing, being, somewhat as an illuminated object receives its light from a source of illumination. Furthermore, it seems to follow that existence must itself necessarily exist as an analytic consequence of what it is (just as "Redness is red" seems to state an analytic necessity). Given these assumptions, the Ontological Argument for God's existence, as Kant later called it, is at least a strong temptation; the argument has had a history identical with the history of logical monism in metaphysics, from Parmenides to Hegel and beyond, as well as a close association with Christian theology.

Revival of Classical Philosophy

Although the realism-nominalism controversy occupied philosophers in the eleventh and twelfth centuries, new ways of thinking in metaphysics were being prepared by translations of Greek and Arabic texts into Latin, especially translations of Aristotle and his Arabian commentators. In the early Middle Ages there was very little firsthand knowledge of the Greek philosophers. Plato's Timaeus, Phaedo, and Meno were known, but the important later dialogues, including Parmenides and Sophist, were not. The Greek texts had been preserved, however, and, especially after the capture of Constantinople by crusaders in 1204, were slowly recovered in the West. In the thirteenth century William of Moerbeke made a literal Latin translation of Proclus's Commentary on the Parmenides ; the commentary contained the text of the Parmenides through the first hypothesis, thereby giving philosophers some firsthand knowledge of that important dialogue.

Aristotle was even less known and understood in the early Middle Ages. Only his logic, the text of De Interpretatione, and the other logical treatises in Neoplatonized versions through Boethius were known. As late as the thirteenth century, two Neoplatonic textsthe "Theology of Aristotle" (actually a compilation from Plotinus's Enneads, IVVI) and the Liber de Causis (a work based on Proclus's Elements of Theology )were wrongly attributed to Aristotle. However, Aristotle's writings had been translated into Syriac by Nestorian Christians in the fifth century and from Syriac into Arabic in the ninth century; Latin translations of Arabic texts were made in the twelfth century and directly from Greek texts by Robert Grosseteste and William of Moerbeke in the thirteenth century. By the end of the thirteenth century most of Aristotle was translated into Latin and was generally available to philosophers. In effect, Aristotle was a new philosopher who appeared on the scene and dominated it as if he were a contemporary; the Metaphysics was the stimulus for such metaphysicians as Albert the Great, St. Thomas Aquinas, John Duns Scotus, William of Ockham, and others in the thirteenth and fourteenth centuries.

thomas aquinas

Thomas Aquinas's metaphysics is an attempt to explain the distinctions between essence and existence, necessary and contingent existence, and particulars and universals, using the language and much of the metaphysical outlook of Aristotle. For Thomas commonsense things like horses and houses do exist in a literal and straightforward sense apart from human observers and also apart from God and paradigms of things in the mind of God. The existence of these commonsense things is not an attribute that they receive from outside; it is not like the light the earth receives from the sun. The existence of finite things in nature is an intrinsic act of existing that these things exercise. But Thomas also held that the ordinary things we experience exist contingently in the sense that their existing is not an analytic consequence of what they are; it is not something they do by nature. There must therefore be a cause (in a metaphysical, not a physical, sense of "cause") of their existence; this must be a necessary being, identified with God, who exists by his own nature. Contingent beings, like horses and houses, are obviously contingent because being composed of matter, their existence is finitethey begin to exist and cease to exist. Matter also accounts for the individuality of things; things that are identical insofar as what they are, or, in other words, things that have the same nature, are still different things because the matter of which they are composed is different. God, on the contrary, is immaterial and, hence, one and unchanging. Thomas, like the Neoplatonists, associated finitude, contingency, plurality, and change with matter. He differed from the Neoplatonists chiefly in his view that finite thingsin particular, human personsexist in their own right (by virtue of a delegated power, as it were) and do not merely participate in the existence of a higher order of being. In this view Thomas agreed with Christian theology and was close to Aristotle.

duns scotus

John Duns Scotus (c. 12661308) seems to have agreed with Thomas that being is not an attribute or a thing in some sense shared by all the things said to be. On the other hand, he criticized Thomas's contrast of essence with existence, arguing that whatever we are aware of must be an essence in some sense, including even individuality or "thisness," which he treats as an attribute of individuals ("this horse here"), distinguishing them from indeterminate beings ("a horse" or "the horse" in general).

william of ockham

William of Ockham (c. 12851349) held that general or indeterminate expressions like "a horse" or "the horse" do not correspond to general beings either in the mind or in reality but refer indifferently to individual horses. He was therefore conventionally called a nominalist in contrast to Duns Scotus, a realist. But William of Ockham's main point seems to be that logical distinctions between universal, particular, and singular are not distinctions between kinds of thingsnot an enumeration of what there isbut are, rather, ways of referring to the one and only one kind of thing that does existnamely, the commonsense things we encounter in everyday experience. For this reason William was probably closer to Aristotle's own view than either Thomas or Duns Scotus; unlike them his explicit aim was to state Aristotle's original position as accurately as he could. But William's successorsnotably, John of Mirecourt and Nicholas of Autrecourtpushed William's views in a direction that anticipated Hume and even twentieth-century logical positivism. We can talk meaningfully only about what we are acquainted with through the senses, and we are acquainted only with particulars, so that all discourse about things refers ultimately only to particulars. The existence of a particular is never an analytic necessity or an analytic consequence of the existence of some other; hence, all meaningful statements about things are only probable.

Descartes to Kant


The revival of metaphysics in the seventeenth century begins with René Descartes (15961650), who has been traditionally considered the originator of modern philosophy. The ideas most commonly associated with Descartes are not original with him. In St. Augustine's writings can be found the cogito ergo sum argument and the view that our own existence is the ultimate certainty since we can be certain of it while the existence of all other things is in doubt. The argument that nothing less than God could have produced the idea of God in the human mind can also be found in St. Augustine. The Ontological Argument had a famous history in the Middle Ages, and the view that physical objects have only geometrical attributes of shape and motion was held by early Greek atomists. The concept of mind as a substantial thing more or less externally attached to the body is hardly original with Descartes. But to say this is to say only that Descartes used a good deal of material from old ruins in his work of "building from the foundation" in metaphysics in order "to establish a firm and abiding superstructure in the sciences."

Descartes was most original in his conception of philosophical method and philosophical truth. No metaphysical assertion is to be believed unless (1) it is understood with the kind of clarity and distinctness that mathematical propositions have and (2) its truth is either so intrinsically obvious that, like the postulates of geometry, it cannot be doubted or it is proved with the same rigor with which theorems are proved in geometry. Descartes's philosophy can be viewed in large part as an effort to reduce the second criterion to the firstthat is, to show that at least in the case of metaphysical propositions, if we understand them clearly and distinctly, we are thereby certain of their truth. These claims made for his or any other metaphysical assertion were revolutionary and most influential. As Descartes and his followers understood them, they amounted to a demand that metaphysics be scientific, understanding by the word scientific being subject to a kind of rigorous intellectual discipline best illustrated in mathematics and the exact physical sciences.


Benedict de Spinoza (16321677), following one interpretation of Descartes's demand for clarity and distinctness in metaphysics, thought of metaphysics as a deductive account of the universe to be developed from a few definitionsnotably, the definition of substance as a being that requires nothing outside itself to be or to be conceivedand self-evident assumptions. His inferences are that there must logically be one and only one substance, uncreated and everlasting; there are an infinite number of attributes of the one substance, only two of which, thought and extension, are known to us; attributes are faces of the one substanceself-contained ways of describing itrather than properties inhering in it the way we commonly think of colors as inhering in physical objects; the universe, described in terms of the attribute extension, is a mechanical system in which all happenings are links in a chain of physical causation; an equally complete causal determinism holds when the universe is conceived in terms of the attribute thought.


Gottfried Wilhelm Leibniz (16461716) was also a follower of Descartes in the sense that he agreed with the demand for a rigorously scientific metaphysics and for clear and distinct ideas in contrast to scholastic verbiage. But while Leibniz agreed that metaphysical assertions are true if clearly and distinctly understood, he interpreted this to mean that metaphysical truths (and truths of reason generally, in contrast to contingent truths of fact) are logically necessary; their denial involves a self-contradiction. Leibniz understood clarity and distinctness in a logical rather than a psychological sense; for him "the true mark of a clear and distinct notion of an object is the means we have of knowing therein many truths by a priori proofs." And we know a truth by an a priori proof when "by the help of definitions or by the resolution of concepts" we "reduce" it to an explicit tautology of the form "A is A " or "A is not non-A. "

Leibniz's metaphysical system is, in effect, an effort to get a clear and distinct idea of the universe in his own rather special sense of clarity and distinctness. And his technical writings in metaphysics consist largely of a series of somewhat different a priori proofs of a number of metaphysical assertions, including the following: There are an infinite number of substances, each of which is logically complete in that it contains in some sense all the properties it ever has exhibited or will exhibit; no two substances exhibit exactly the same properties ("identity of indiscernibles"); a complete description of any one substance would be a description of the entire universe "from a point of view"; space and time are relations among things, not things in their own right; the appearance of causal relations between things is illusory, reflecting God's deliberate prearrangement rather than any real influence exerted by one thing on another. In proving these assertions, Leibniz relied on a principle of sufficient reason stating, in effect, that there is always a rational explanation for a fact. But the principle of sufficient reason is not really a description of the universe for Leibniz. What it really expresses is the idea that in principle any truth can be given an a priori proof; the underlying thought is that when any statement is understood with perfect clarity and distinctness, it will be seen to be an explicit tautology.


Spinoza and Leibniz are usually grouped with Descartes as rationalists, as contrasted with British empiricists, represented in the seventeenth century by John Locke (16321704). But in an important way Locke, too, was a follower of Descartes; he was also mainly interested in replacing scholastic jargon with clear and distinct ideas and opening the way for the sciences. Locke's main contribution to metaphysics lies in his critical discussion of substance and essence. Descartes had laid it down as an indubitable common notion that "nothing is possessed of no attributes, properties, or qualities," so that "when we perceive any attribute, we therefore conclude that some existing thing or substance to which it may be attributed, is necessarily present." Locke did not deny that this is a valid inference; he does not question the distinction between thing and property. But he asked what we know (or, as he phrased it, "What is our idea") of a thing beyond its attributes, powers, and so forth. His answer was that we have no clear and distinct idea at all; we know only what the common notion itself saysnamely, that if there are attributes, there must be something underneath that has them. We have no clear idea what is underneath or what "underneath" means in this context. We know only the attributes, powers, and so on (indiscriminately called qualities by Locke) of things, not the things in themselves.

Here, however, Locke was criticizing only the notion of substance as substratum underlying properties. And this is a concept of substance minimized by Aristotle and never stressed by metaphysicians. Thomas Hobbes, for example, argued that the accidents of body, such as shape or hardness, are the very "manner of our conception of body." To ask for a description of body apart from its accidents would be, for Hobbes, a senseless request. Locke's more important and original criticism concerns the notion of essencethe notion of what a thing is in contrast to what it is made of, how big it is, its location, its age, and the like. Locke argued at length that the distinction is a useless one; the question "What is X ?" can be answered only by enumerating X 's observed properties, and (most important) we cannot see any logical necessity for the coexistence of just these and not some other combination of properties. We do not therefore have any knowledge of real essences except in cases where we ourselves construct the thing in question, as in mathematics. Locke reasoned, roughly, that we know the attributes and powers of things only through the simple sense impressions we have of them. Since, for the most part at least, there are no noticeable necessary connections between simple sense impressions, we cannot explain why things appear as they do but can only describe how they do appear. Locke never denied there is a reason for things' having just the attributes and powers they have and not some others, but he denied our ability ever to have clear and distinct ideas of these reasons. The effect of Locke's view is to deny the possibility of metaphysical knowledge when metaphysics is conceived of in the way Francis Bacon, for example, conceived of it, as a very general but still empirical and even experimental study of the formal causes of things, as distinguished from natural science, which studies material and efficient causes.

berkeley and hume

Locke never questioned the distinction between ideas of things and the qualities in things that cause ideas, and he thought we have at least a "relative and obscure" idea of a thing in contrast to its qualities. But George Berkeley (16851753) questioned both distinctions, partly on grounds of fact but more especially on grounds of a general theory of meaning. For Berkeley the grammatical distinction between subject and predicate has no counterpart in a distinction between things and properties; we can talk meaningfully only about what we are acquainted with, and we are acquainted only with individual colors, sounds, tastes, and the like. Since these individual colors, sounds, and tastes have characteristics that are admittedly mental, such as pleasantness and painfulness, and are relative to the human observer in various ways, Berkeley concluded we can talk meaningfully only about mental entities or, as he called them, following the usage of Descartes and Locke, ideas in the mind. In this way Berkeley arrived at phenomenalism (things exist exactly as they appear to the senses) and idealism (things exist only as objects of conscious perception; their being consists in being perceived). Berkeley was not thoroughgoing in these positions; he thought it meaningful to talk about other minds and about God even though we cannot directly perceive such phenomena.

These qualifications, however, were swept aside in the thoroughgoing phenomenalism of David Hume (17111776). Hume criticized the notion of a mind as distinguished from the ideas said to be in the mind for the same reasons that Berkeley criticized the notion of matter. According to Hume, the notion of existence itself signifies nothing beyond a greater or less degree of force and vivacity attaching to sense impressions and mental images. Our beliefs in the continuous existence of physical objects and the presence of causal connections between them are explained as effects of habitual associations of ideas for which there is, strictly speaking, no evidence. Although Hume is usually and correctly called an empiricist in contrast to speculative metaphysicians like Leibniz or Spinoza, there is a sense in which he was as much a rationalist as his contemporary Christian Wolff. Hume assumed that the ultimate subject of thought and discourse must be something we are directly conscious of, that we are directly conscious only of individual sensations (or their more or less faint copies), and that whenever we can discriminate one sensation or feeling from another, these exist separately and hence count as different things. These assumptions amount to a theory of empiricism, but they are not themselves empirical assertions. Nor, on the other hand, are they necessary truths in Leibniz's sensepropositions whose denial involves a self-contradiction. In effect, they demonstrate how Hume understood Descartes's demand for clarity and distinctness in metaphysics and are analogous to Leibniz's principle of sufficient reason, which expressed his understanding of the same demand. For Leibniz clarity and distinctness meant, in the end, reduction to an explicit tautology; for Hume clarity and distinctness meant, in the end, reduction to directly verifiable assertions about sensations and feelings.


By the time of Hume's death, in 1776, the difficulties and ambiguities in Descartes's program for metaphysics were apparent. Cartesianism inspired both the speculative constructions of Spinoza, Nicolas Malebranche, Leibniz, and others and the critical andat least, on the surfaceincreasingly skeptical philosophies of Locke, Berkeley, and Hume. This, at least, was the view taken by Immanuel Kant (17241804). It led Kant to ask whether metaphysics could be scientificwhether metaphysical knowledge is even possible and if not, how the questions that gave rise to metaphysics in the past could be answered. In discussing these problems, Kant made a very penetrating analysis of metaphysics as a discipline and a set of assertions and as a "human propensity"; Kant's contribution, apart from his own system, was to raise questions about what metaphysical assertions, as distinguished from scientific assertions, are, about the sense in which they claim truth, and about the grounds on which they are to be believed or disbelieved.

From Kant's point of view the history of metaphysics (insofar as metaphysics had claimed to be a science) had been a story of dogmatism versus skepticism. Dogmatists like Leibniz have held that metaphysics can, on the basis of purely logical or conceptual considerations, answer with absolute certainty questions about the origin of the universe, the existence of God, and the immortality of the soul. "Dogmatists," as Kant used the word, can be materialists, panpsychists, or dualists, monists or pluralists. What they share is a confidence that a metaphysician can give an account of the nature of reality using a priori reasoning. Skeptics, on the other hand, are empiricists; for them there are no universal and necessary truths of fact and reasoning alone, in contrast to observing and experimenting, is of no use whatsoever in answering questions about the existence or natures of things. For Kant this alternating dogmatism and skepticism was the effect of alternating overconfidence and lack of confidence in the abilities of the human mind. Accordingly, his critical philosophy is an effort to show what human knowledge is like and what its limits must necessarily be.

Dogmatic metaphysics in Kant's sense is not mere ad hoc speculation; it is an understandable and correctable misuse of basic concepts. The dogmatic metaphysician rightly sees that we actually use concepts like substance (in contrast to accidents) or causation (in contrast to mere succession). He also correctly saw that we are a priori certain of such things as the irreversibility of time or the impossibility of two physical objects' occupying the same space. But he uncritically concluded that we have a power other than sense perception of knowing what things are like, whereas the true conclusion is that we ourselves determine in advance what any object of knowledge must be like. The questions we ask about things and the answers we look for are determined by our own a priori forms of perceiving (space and time) and of judging (every attribute must belong to some substance, every event must have some cause and so on). Mistaking these a priori forms of perceiving and judging for descriptions of things-in-themselves, the dogmatic metaphysician is led to speak of ultimate subjects and first causes. In Kant's view these speculations are misguided and even meaningless. But metaphysical ideas, such as an ultimate subject or a first cause, do have a regulative use in encouraging us never to be satisfied with what we actually know at any given time. And Kant did not infer that the beliefs that metaphysicians have tried to provebeliefs in personal immortality or in the existence of Godare illusory. These beliefs are not like belief in perpetual motion machines; they can be justified and can even be supported by argumentsbut by moral arguments, not speculative arguments. Dogmatic metaphysics can thus be explained and even in a sense vindicated. It cannot be taken seriously as a source of knowledge, however.

Metaphysics since Kant

Kant's own metaphysical position was idealistic. Aristotle's categories reappear somewhat altered in Kant's philosophy as forms of judgment. The most immediate and obvious effect of Kant's thought can be seen in the idealistic systems of his younger German contemporaries and successors, Johann Gottlieb Fichte (17621814), Friedrich Schelling (17751854), Arthur Schopenhauer (17881860), and, above all, Georg Wilhelm Friedrich Hegel (17701831).


Among the idealists, however, it was Hegel whose metaphysical outlook has probably had more general intellectual influence than that of any other single recent philosopher. Kant's critical idealism assumes a clear-cut contrast between what is given in experience (sense impressions) and the forms we use to arrange and interpret what is given. In general, Kant assumed a clear distinction between what is directly perceived and what is inferred or constructed by the mind. Hegel's absolute idealism consists largely in denying this contrast; for him the underlying notion of a plurality of separately existing particulars, uniquely located in space and time (conceived as containers in which things are unambiguously placed), was a false, even a logically incoherent notion. He appears to have arrived at this conclusion from the assumptions that things-in-themselves cannot be distinguished meaningfully from things as we know them and that things as we know them gradually take shape in our consciousness and become defined only in contrast to other things. On this basis he concluded that all things shade off into their opposites and that the connections between things we establish in thought are as much a part of the things as their so-called inherent properties. Hegel was thus led to the monistic position that there is only one kind of substance and only one truly substantial entity. His idealism is an evolutionary pantheism in which the only self-subsistent reality is spirit; it contrasts not only with materialism in the traditional sense but with any metaphysical position associating reality with some kind of hard definiteness.

Outside of philosophy proper Hegel's influence was apparent mainly in inspiring a view of things as phases of a living and growing history; institutions, languages, ideas, even philosophies themselves, were seen as quasi-living and even quasi-personal phenomena whose histories were to be sympathetically grasped and appreciated rather than appraised by themselves on the basis of a priori standards. This widely held view has been encouraged by Hegel's absolute idealism, in which reality is associated with self-expression and all-inclusiveness, not with given things or facts. Within philosophy Hegel's influence can be seen in the many evolutionary idealisms of the nineteenth and early twentieth centuries. It can also be seen in the more rigorous and critical thought of Hegelians like F. H. Bradley (18461924) and J. M. E. McTaggart (18661925). Bradley in particular stressed the negative side of Hegelianism, finding logical antinomies in the ordinary concepts of things, properties, relations, causation, and space and time. McTaggart, on the other hand, attempted to rephrase Hegelianism as a clear and straightforward speculative system. This tradition is continued by such contemporary metaphysicians as Brand Blanshard.

metaphysics and pragmatism

Largely through the influence of German idealism and especially of Hegel, metaphysics in the nineteenth century generally meant a priori cosmology and, in particular, an idealist cosmology contrasted and even opposed to the alleged mechanistic and materialist assumptions of science. Auguste Comte's positivethat is, nonmetaphysicalphilosophy did not attack metaphysics as such; it attacked speculative philosophy as a way of providing substitutes for religious beliefs. Popularly, metaphysics was associated with religion, idealism, and spiritualism and opposed to science, which was associated with empiricism and materialism. But this concept of metaphysics, although still popular, was only a temporary alignment in the history of metaphysics and was strongly challenged even in the nineteenth century.

A notable example is the American philosopher C. S. Peirce (18391914). Peirce was a Hegelian to the extent that he believed there are no self-identical particulars that can be unambiguously located or identified. Reality is indeterminate both in the sense that it is characterized by novelty and unpredictability and in the sense that things are not just what they are but shade off continuously into other things; reality is an evolutionary process that is in some sense rational. But for Peirce this outlook is required by reflection on experience and the sciences, metaphysics itself being an observational science whose job is "to study the most general features of reality and real objects" and whose backward condition is due chiefly to the fact that "its leading professors have been theologians." Science and experience force us to give up the concept of definite, unambiguous facts and fixed a priori assumptions; science is a community of inquirers sharing methods and a kind of moral and intellectual discipline rather than a body of knowledge or a set of assumptions (as Kant, for example, had thought). Metaphysics for Peirce was an attempt to describe how reality must seem to men imbued with science; reality is what will eventually be agreed on by the community of inquirers; general laws and relations among things are real since these, rather than particular facts, are the objects of scientific research. Peirce's concept of metaphysics influenced John Dewey (18591952), and largely through Dewey it has had considerable importance in recent American philosophy. Like Peirce, Dewey hoped metaphysics could be a descriptive account of generic traits exhibited in all experience.

logical positivism

The mainstream of metaphysics in the nineteenth and early twentieth centuries was idealistic; metaphysicians responded to Kant by constructing systems meant to extend or deepen Kant's critical idealism. But another response was to question dogmatic metaphysics more profoundly than Kant himself. This more radical questioning was begun by such nineteenth-century philosophers of science as Ernst Mach (18391916), who criticized the notion that general concepts of science (for example, force) described unobserved entities or that scientific laws are more than convenient formulas for summarizing observations.

This line of criticism has been most forcefully and systematically carried out by twentieth-century logical positivism. For the logical positivists metaphysics has a special meaning; an assertion is metaphysical if it purports to make a statement of fact but fails to do soand therefore fails to have a meaningsince no observations count as evidence for or against it. This special use of metaphysics should be understood in the context of the belief of logical positivists that traditional questions of metaphysics do have a point, but a point that traditional formulations of the questions obscure. They are not questions about things at all but about languagein particular, about the types of words and sentences and the logical vocabulary needed to express the findings of the sciences.

The hope of some logical positivists was that if traditional metaphysical questions were translated into questions about the language of science, the answers would be immediately and clearly seen. If, for example, "Does nonbeing exist?" is phrased as "Are sentences of the form 'X is not an F ' ever true?," the answer is obviously "Yes." But it became increasingly clear that in the construction of languages expressing the findings of the sciences problems analogous to traditional metaphysical problems occur. For example, some positivists suggested that sentences such as "Two plus two equals four" owe their truth to linguistic usage rather than to a necessary connection between things, perceived by reason, as past metaphysicians often assumed. Critics pointed out, however, that since it is an empirical fact that we use language as we do, the substitution of "true by virtue of linguistic convention" for "necessary truth" threatens to make "Two plus two equals four" a merely empirical statement. Thus, a distinction is needed between what we merely do not say and what our language will not allow us to say. This does not, of course, mean that nothing was gained over traditional metaphysics, but it does mean that the achievement of logical positivism has been to elucidate or reconstruct traditional metaphysical issues rather than give a method for easily solving them. Accordingly, logical positivists now tend to accept metaphysics in its conventional sense, as the name of a legitimate part of philosophy, along with the special use of metaphysical to refer to pseudoinformative assertions that in reality are meaningless.

ordinary-language philosophy

The logical positivists were strongly influenced by Bertrand Russell's view that much of traditional metaphysics resulted from a superficial and hasty analysis of ordinary language as well as by the view of Russell and Peirce that past failures of metaphysicians were due to a narrowly restricted logic that prevented them from analyzing ordinary language correctly. The notion that traditional metaphysics resulted from a superficial understanding of ordinary language has been developed independently of logical positivism (although sometimes popularly confused with it) by Ludwig Wittgenstein, Gilbert Ryle, and a large number of contemporary British and American philosophers. Like the logical positivists the ordinary-language philosophers agree that traditional metaphysical questions are in some sense intelligible but need to be radically reformulated; unlike the positivists they are not concerned with rephrasing them as questions about the language of science. They want to show, rather, how metaphysical questions can be solved (or dissolved) by exhibiting the less obvious but essential presuppositions that give linguistic expressions the meanings they actually have in ordinary discourse. Positively, ordinary-language philosophers use linguistic analysis (for example, naming, referring, describing, and so on) to deal with traditional metaphysical issues, and like logical positivists they accept metaphysics in this positive sense as a legitimate area of philosophy.

phenomenology and existentialism

Both logical positivism and ordinary-language philosophy could be viewed as extensions of Kant's criticism of dogmatic metaphysics; they both sharply contrast with Hegelianism and, in general, with the more or less speculative metaphysical systems inspired by Kant's idealism. A third major development in nineteenth-century and twentieth-century metaphysics, represented by phenomenologists and existentialists, agreed with Hegelians that metaphysics is not an observational science in any ordinary sense and also agreed with analytically minded philosophers that a priori reasoning cannot establish anything about the nature of reality. Accordingly, these philosophers sought new and unconventional ways of experiencing or encountering reality. This response is shown by more conventional metaphysicians like Henri Bergson (18591941), who stressed the inability of spatializing and static conceptual thinking to represent correctly the reality of immediate experience, especially its temporal flow, or by Alfred North Whitehead (18611947), who stressed imaginative feeling and emotion as a way of gaining access to the inner natures of things. Phenomenologists hold that common sense and science presuppose a more primitive experience that can be grasped by a deliberately naive description of how things actually appear to us; existentialists argue that the subject of metaphysics is a reality that cannot be described in an emotionally neutral way but is in some sense possessed or encountered in personal commitment to a cause or in facing the certainty of one's own death. Phenomenology and existentialism have been combined by systematic philosophers like Martin Heidegger and Jean-Paul Sartre, whose systems attempt to express an intuitive understanding of time, contingency, and particularity as these are experienced in human life.

philosophical analysis

In the English-speaking world at least, the most original and important contributions to metaphysics at the present time come from analytic philosophers largely influenced by logical positivism or ordinary-language philosophy. These philosophers see the present situation in metaphysics somewhat as Aristotle did when he reviewed the history of metaphysics up to his own time. In a sense, Aristotle thought, everything had been said, but in a sense nothing had been said because the early philosophers were vague and inarticulate. Contemporary metaphysicians, however, are in a better position to review and analyze the history of their subject than was Aristotle, partly because the history itself is so much richer and partly because contemporary insights make the work of past metaphysicians more intelligible.

See also Albert the Great; Analysis, Philosophical; Anaximander; Anaximenes; Anselm, St.; Aristotle; Augustine, St.; Bergson, Henri; Berkeley, George; Blanshard, Brand; Boethius, Anicius Manlius Severinus; Bonaventure, St.; Bradley, Francis Herbert; Comte, Auguste; Descartes, René; Dewey, John; Duns Scotus, John; Erigena, John Scotus; Existentialism; Fichte, Johann Gottlieb; Galileo Galilei; Grosseteste, Robert; Hegel, Georg Wilhelm Friedrich; Heidegger, Martin; Heraclitus of Ephesus; Hobbes, Thomas; Hume, David; Iamblichus; Idealism; Kant, Immanuel; Leibniz, Gottfried Wilhelm; Leucippus and Democritus; Locke, John; Logical Positivism; Mach, Ernst; McTaggart, John McTaggart Ellis; Melissus of Samos; Metaphysics, Nature of; Neoplatonism; Newton, Isaac; Ontological Argument for the Existence of God; Parmenides of Elea; Peirce, Charles Sanders; Phenomenology; Plato; Plotinus; Porphyry; Pragmatism; Proclus; Pythagoras and Pythagoreanism; Russell, Bertrand Arthur William; Ryle, Gilbert; Sartre, Jean-Paul; Schelling, Friedrich Wilhelm Joseph von; Schopenhauer, Arthur; Spinoza, Benedict (Baruch) de; Thales of Miletus; Thomas Aquinas, St.; Whitehead, Alfred North; William of Champeaux; William of Moerbeke; William of Ockham; Wittgenstein, Ludwig Josef Johann; Wolff, Christian; Zeno of Elea.


general works

Copleston, F. C. A History of Philosophy, 7 vols. London: Burns, Oates and Washbourne, 1946. A careful, detailed work requiring close study; probably the most comprehensive and scholarly general history available. Includes excellent bibliographies and sections on metaphysics in chapters on individual philosophers.

De George, Richard T., ed. Classical and Contemporary Metaphysics: A Source Book. New York: Holt, Rinehart and Winston, 1962. A book of readings emphasizing contemporary authors but also including selections from classical texts.

Gilson, Étienne. Being and Some Philosophers, 2nd ed. Toronto: Pontifical Institute of Mediaeval Studies, 1952. A challenging essay on the history of metaphysics argued with great subtlety by an outstanding Roman Catholic philosopher.

Kaufmann, Walter, ed. Philosophic Classics, 2 vols. Englewood Cliffs, NJ: Prentice-Hall, 1994. A comprehensive sourcebook for the history of philosophy, with some excellent introductory essays.

Lovejoy, Arthur O. The Great Chain of Being. Cambridge, MA: Harvard University Press, 1936. Traces some main themes of metaphysics from the Greeks to the nineteenth century; a wide-ranging essay in the history of ideas rather than the conventional history of philosophy.

Smith, T. V., ed. Philosophers Speak for Themselves, 4 vols. Chicago: University of Chicago Press, 1956. A collection of readings from Thales to Kant.

Whitehead, A. N. Adventures of Ideas. New York: Macmillan, 1933. Suggestive and sometimes profound nontechnical essays on movements in science and philosophy by a great twentieth-century metaphysician.


Burnet, John. Early Greek Philosophy, 4th ed. New York, 1930. Lucid and authoritative; contains translations of some important fragments.

Freeman, Kathleen. Ancilla to the Pre-Socratic Philosophers. Cambridge, MA: Harvard University Press, 1948. English translations of the surviving pre-Socratic writings collected in Hermann Diel's monumental Fragmente der Vorsokratiker.


Cornford, F. M. Plato and Parmenides. New York: Liberal Arts Press, 1957. Translations with running commentaries of Parmenides' Way of Truth and Plato's Parmenides ; for advanced students.

Cornford, F. M. Plato's Theory of Knowledge. New York: Liberal Arts Press, 1957. Translations with running commentaries of Plato's Theaetetus and Sophist.

Lynch, William F. An Approach to the Metaphysics of Plato through the Parmenides. Washington, DC: Georgetown University Press, 1959. An attempt to see the Parmenides as a straightforward assertion of "basic positions in Platonic metaphysics."

Ryle, Gilbert. "Plato's Parmenides." Mind 48 (1939): 129151, 302325. Article by a leading contemporary British ordinary-language philosopher; suggests a modern reading.

Vlastos, Gregory. "The Third Man Argument in the Parmenides." Philosophical Review 63 (3) (1954): 319349. Technical but clear and acute analysis of the third-man argument against the theory of ideas in the first half of the Parmenides.


Aristotle. Metaphysics. Translated by Richard Hope. New York: Columbia University Press, 1952. With an analytical index of technical terms; a useful edition for advanced students. Index contains Greek terms with Latin equivalents.

Brumbaugh, Robert S. "Aristotle's Outline of the Problems of First Philosophy." Review of Metaphysics 7 (3) (1953). A brief but very helpful analysis of the organization of the Metaphysics.

Owens, Joseph. The Doctrine of Being in the Aristotelian Metaphysics. Toronto: Pontifical Institute of Mediaeval Studies, 1951. Highly technical but original and forcefully argued interpretation of the Metaphysics.


Bréhier, Émile. The Philosophy of Plotinus. Translated by Joseph Thomas. Chicago: University of Chicago Press, 1958. Readable sympathetic account of Plotinus and his school by a modern French historian of philosophy.

Porphyry. Isagoge. Translated by J. Tricot. Paris: J. Vrin, 1947. A translation into French of the complete text, with introduction and notes.

early middle ages

Anselm. Proslogium and Monologium. Translated by S. N. Deane. La Salle, IL: Open Court, 1962.

Malcolm, Norman. "Anselm's Ontological Arguments." Philosophical Review 69 (1) (1960): 4162. A closely reasoned analysis of Anselm's argument and medieval and modern criticisms.

late middle ages

Copleston, F. C. Aquinas. Harmondsworth, U.K.: Penguin, 1955. Clearly written, relatively simple introduction to Thomas; contains a useful bibliography.

Moody, Ernest A. The Logic of William of Ockham. New York: Sheed and Ward, 1935. A scholarly study of William of Ockham and medieval logic and metaphysics; difficult but searching and persuasive.

Thomas Aquinas. Concerning Being and Essence. Translated by George C. Leckie. New York: Appleton, 1937. Difficult but important treatise on a basic distinction in Thomistic metaphysics.

seventeenth century

Aaron, R. I. John Locke. London, 1955.

Balz, A. G. A. Descartes and the Modern Mind. New Haven, CT: Yale University Press, 1952.

Beck, Leslie J. The Method of Descartes. Oxford: Clarendon Press, 1952.

Descartes, René. Selections. Edited by R. M. Eaton. New York, 1927.

Hampshire, Stuart. Spinoza. Harmondsworth, U.K.: Penguin, 1987. An excellent exposition and criticism with a general concluding chapter on the nature of metaphysics.

Jackson, Reginald. "Locke's Distinction between Primary and Secondary Qualities." Mind 37 (1929): 5676. Explains and criticizes Locke's contrast between ideas in the mind and qualities in things and between primary and secondary qualities.

Leibniz, Gottfried Wilhelm. The Monadology and Other Philosophical Writings. Edited by Robert Latta. London, 1948.

Leibniz, Gottfried Wilhelm. New Essays concerning Human Understanding. Translated, with notes, by Alfred G. Langley, 3rd ed. La Salle, IL, 1949. A standard edition containing some very interesting but little-known essays by Leibniz in an appendix.

Locke, John. An Essay concerning Human Understanding. New York: Dover, 1958.

Whitehead, A. N. Science and the Modern World. New York: Macmillan, 1925. Early chapters contain a brilliant critique of seventeenth-century and eighteenth-century science and philosophy.

eighteenth century

Kant, Immanuel. Prolegomena to Any Future Metaphysics. Edited by Lewis White Beck. New York: Liberal Arts Press, 1951. A good introductory text by a leading authority on Kant; contains a useful bibliography.

Smith, N. K. Immanuel Kant's Critique of Pure Reason, 2nd ed. New York, 1933. A classic translation of Kant's major work.

Warnock, G. J. Berkeley. Harmondsworth, U.K.: Penguin, 1953. An exceptionally good introductory work; highly critical of some of Berkeley's leading arguments.

metaphysics since kant

Ayer, A. J., ed. Logical Positivism. Glencoe, IL: Free Press, 1959. A collection of the most important and influential papers in the logical positivist movement; includes an unusually complete bibliography covering the entire range of twentieth-century analytic philosophy.

Findlay, J. N. Hegel. New York: Humanities Press, 1964. A very clearheaded sympathetic exposition of Hegel's system.

Passmore, John. A Hundred Years of Philosophy. London: Duckworth, 1957. A useful and very well written survey of philosophy since 1860; emphasizes metaphysics and theory of knowledge in English-speaking countries.

Royce, Josiah. The Spirit of Modern Philosophy. Boston and New York, 1926. Lectures on post-Kantian philosophy, especially nineteenth-century German idealism.

White, Morton. Toward Reunion in Philosophy. Cambridge, MA: Harvard University Press, 1956. A forceful and lively essay on main issues in recent British and American philosophy; Part I is devoted to recent metaphysics.

Wolheim, Richard. F. H. Bradley. Harmondsworth, U.K.: Penguin, 1959. An introduction to Bradley; quite critical but closely and skillfully argued.

Roger Hancock (1967)