Metaphysics: Renaissance to the Present

Metaphysics, in its most basic sense, is an account of what exists. It may include accounts of what sorts of things exist; of what really exists as opposed to what merely appears to exist; of what exists necessarily rather than by accident; of what it is that underlies everything else; or of the most general laws governing existing things. This article will describe some of the most important metaphysical positions that have appeared since the Renaissance and, where space permits, some of the reasons that have motivated the philosophers who hold them. The dates given for different eras are particular to this discussion. They name the year of birth of the earliest philosopher covered in each section and the year of death of the latest.

The Renaissance (1433–1617)

Better and more widely available texts of the writings of Plato mark the Renaissance. The new, widespread distribution of Platonic and Neoplatonic works, due in large part to the work of Marsilio Ficino (1433–1499) led to a major revival of those views. One of Ficino's most influential views is his account of a hierarchy of perfection among existing things in which the highest thing, God, possesses the most perfection and the lowest thing, the body, the least.

The philosophy of the Renaissance remained, however, generally Scholastic. That is, it was dominated by Aristotelian views as codified by medieval commentators. Among Scholastics, Francisco Suárez (1548–1617) is notable for offering a definition of metaphysics as the science of being qua being, which distinguishes metaphysics from less lofty accounts of accidental features of existing things and focuses inquiry on the nature of being itself. Suárez's seminal work, Disputationes metaphysicae (1597), also offered an original account of the metaphysical status of universals, in which it is true that only individual things exist but contrary to nominalism—the view that universal terms are merely labels for arbitrary collections of individuals—it is also true that universals are abstractions from nonconventional similarities among individuals.

The Early Modern Period (1561–1753)

Early modern metaphysics is in large part a response to the challenges that dramatic advances in physics and astronomy presented for theology and Aristotelian philosophy. Francis Bacon (1561–1626) is the figure who perhaps best marks the transition between Renaissance and early modern philosophy. Bacon's major work, The New Organon, as its title suggests, was an attempt to supplant Aristotle's authority. Two doctrines of that work form the basis of many of the period's debates. First, Bacon asserted that a traditional part of metaphysics, the inquiry into the final causes, or purposes, of nature, is barren, thereby divesting natural science of an important theological element. Second, Bacon denied that forms, understood as abstract natural kinds, are principally what exists. Metaphysics, on Bacon's view, is the study of first and formal causes in nature. It is, in short, the study of the most general laws or reasons by which natural events may be understood.

René Descartes (1596–1650) followed Bacon in denying that explanations in terms of final causes are appropriate in the sciences. He defended the existence and perfection of God but focused his metaphysics, as Bacon did, on providing an account of the natural world. In his most important philosophical works, Meditations on First Philosophy (1641) and Principles of Philosophy (1644), he argued that there are two basic kinds of substances or things with independent existence: minds and bodies. Any substance is characterized by a property necessary for its existence, which Descartes called in different places its nature, essence, or attribute. The nature of mind is thought; of body, extension. Substances have, in addition, properties that are not essential to them and that they can gain or lose without themselves going out of existence. Such properties are called modes or affections.

Descartes's metaphysics is best known for one argument and a problem that the argument generates. He argued that the existence of the self can be known for certain just because, at the very time one doubts the proposition "I exist," one is at the same time thinking and therefore existing (Descartes, vol. 1, pp. 194–195). From this argument, often referred to as "the cogito," Descartes eventually concluded that the essence of mind—and so perhaps of the person—is thought. However, it is clear that people have and are intimately aware of their own bodies. The mind-body problem arises from an attempt to give an account of human nature. Are people essentially, minds, bodies, or both? Moreover, if people are both, the relationship between mind and body needs to be explained. For Descartes, this latter problem was especially difficult. He endorsed a view of perfection in the world much like that of Ficino, in which minds are much more perfect than bodies, so he had to explain in his theory of perception how something less perfect apparently causes changes in something more perfect.

Final Causes

[The mind] falls back on things that are more familiar, namely final causes, which are plainly derived from the nature of man rather than of the universe, and from this origin have wonderfully corrupted philosophy. (Bacon, 1620, p. 44)

When dealing with natural things we will, then, never derive any explanations from the purposes which God or nature may have had in view when creating them and we shall entirely banish from our philosophy the search for final causes. (Descartes, 1647, vol. 1, p. 202)

Nature has no end set before it, and … all final causes are nothing but human fictions. (Spinoza, 1660s? Ethics I Appendix)

Whatever Descartes may have said, not only efficient causes, but also final causes, are to be treated in physics, just as a house would be badly explained if we were to describe only the arrangement of its parts, but not its use. (Leibniz, 1702, pp. 254–255)

May I regard purpose-like orderings as intentions… ? Yes, but … it must not matter at all whether you say, "God has wisely willed it so" or "Nature has wisely so ordered it." (Kant, 1781, p. 620)

[Spirit] is in itself the movement which is cognition—the transforming of the in-itself in that which is for-itself, of substance into subject. (Hegel, 1807, p. 488)

Benedictus, or Baruch, de Spinoza (1632–1677) published during his lifetime a well-received commentary on Cartesian philosophy. Many of his best-known metaphysical positions, which are found in their most mature form in his posthumously published Ethics, can be understood as reactions to Cartesianism. Spinoza identified God with Nature and defended against Cartesian dualism a substance monism in which God is the only substance (EIp14) and possesses all attributes (Spinoza, EId6), including both extension and thought. Spinoza rejected any purpose in nature. (Spinoza is cited here in the customary fashion. For example, EIIp7 means Ethics, Part II, proposition 7.) He defended, largely against Descartes, necessitarianism (EIp33), the view that things could not have been any other way than the way they are, and universal determinism (EIp28–Ip29), in which every existing mode is the effect of some efficient cause. Spinoza addressed the mind-body problem by means of the doctrine known as parallelism, in which mind and body do not interact (EIIp7). Instead, the chain of causes and effects may be understood equally well as a chain of exclusively mental or exclusively physical events.

John Locke (1632–1704), whose philosophy is, much like Bacon's, an attempt to vindicate mechanistic science, adopted a slightly different notion of substance. For Locke, substances are much the same things as Cartesian substances—persons, God, angels, and ordinary material objects. Substances are so designated, however, not because of their independent existence but because they form a substratum for clusters of properties in which those properties inhere and which can survive change in those properties. Although Locke, like his predecessors, described modes at length, he considered them properly ideas rather than properties of substance. The important, knowable properties of substance, in his view, are qualities. In his Essay concerning Human Understanding, Locke famously (or notoriously) defended Robert Boyle's (1627–1691) distinction between primary qualities, such as extension, which really are in substances, and secondary qualities, such as white, which are mere powers to produce certain sensations in people (Locke, 2.8.12–13). This doctrine may be a result of Locke's attempt to ground corpuscularian physical theories, in which extension and other primary qualities were supposed to explain color perceptions and other secondary qualities.

Gottfried Leibniz (1646–1716) was perhaps the most sophisticated metaphysician of the early modern period. He read his predecessors and contemporaries widely and engaged with their views in a variety of contexts. Leibniz was by temperament conciliatory, and his sympathy toward Scholasticism emerges most clearly in his attempt to reintegrate final causes into metaphysics, both at the level of scientific explanation and at the very general level (pp. 52–55). Leibniz's fundamental metaphysical principle, the Principle of Sufficient Reason, is the doctrine that there is reason for every state of affairs. At the most general level, this reason must be in terms of God's purposes: God chooses that the world be this world rather than other possible worlds because this one is the best of all possible worlds (pp. 96–97). The Principle of Sufficient Reason formed the basis for some powerful criticisms of Newtonian physics. It is also the principal target of Voltaire's satire, Candide.

From at least the 1680s, Leibniz understood substances in grammatical terms, as subjects of predication that cannot themselves be predicated of something else. For example, "a king" can be either the subject or predicate of a proposition, so it is not substance; "Alexander," however, can only be a subject, so Alexander is a genuine substance (pp. 41–42). Because Leibniz conceived of each substance as a complete concept or a subject with a comprehensive list of true predications of it, he denied that substances change. So he denied, at the strictly metaphysical level, causal interaction among substances (p. 47). His grammatical conception of substance caused him to endorse a version of idealism, the view that substances cannot be material (p. 79) and in 1714 the theory of monads, his mature metaphysics in which all things either are or are composed of simple, indivisible, inalterable, indestructible, perceiving things.

George Berkeley (1685–1753) formulated an influential version of idealism. He was influenced by Leibniz's views on material objects and also by the Cartesian Nicolas Malebranche's (1638–1715) criticisms of accounts of causal influence among bodies. His most explicit target, however, was Locke's version of the distinction between primary and secondary qualities. Berkeley argued that Locke was right to think that sensations such as pain and white that are caused in people do not resemble their objects but that Locke had no reason for thinking that the perception of extension and other purported primary qualities is different. In either sort of case, one has access only to one's sensations, and these are certainly ideas. Berkeley identified ordinary objects and the physics of ordinary objects, then, as concerning ideas rather than their cause, which can only be God.

Kant's "Copernican Revolution" in Metaphysics

Up to now it has been assumed that all our cognition must conform to the objects; but all attempts to find out something about them a priori through concepts that would extend our cognition have, on this presupposition, come to nothing. Hence let us once try whether we do not get farther with the problems of metaphysics by assuming that objects must conform to our cognition, which would agree better with the requested possibility of an a priori cognition of them, which is to establish something about objects before they are given to us. (B xvi, p. 110)

David Hume (1711–1776) followed Berkeley in construing ordinary objects as ideas (1.2.6). He was, however, skeptical about the causes of ideas and indeed is best known for his skepticism about causality generally. Hume denied that any sort of necessary connection could be known through experience and so denied all causal connections of the sort asserted by many of his predecessors. He redescribed causal relations as laws concerning the causal conjunction of events of one sort with events of the other. Hume has traditionally been understood as moving from causal language in the description of nature, in which events of one sort are said to cause events of another sort, to the language of laws, in which, more modestly, events of one sort are said to follow events of another sort with lawlike regularity.

German Idealism (1724–1831)

German idealists attempted to preserve causal laws and other necessary truths about objects by emphasizing the role of the self in understanding objects. As the movement developed, figures such as Gottlieb Fichte (1762–1814) went further, arguing that, in a sense, the self creates objects.

Immanuel Kant (1724–1804), in his Critique of Pure Reason, defended the view, largely against Hume, that there are basic a priori laws, including causal laws, governing all objects of experience. Kant's "Copernican Revolution" in metaphysics changed the focus of metaphysical inquiry from nature exclusively to the thinking self as it understands nature. He argued that there are concepts—Categories—and space and time—Forms of Sensible Intuition—by which one understands and experiences things. Because one cannot but think things under these Categories and Forms, they are a priori conditions of different kinds of thought and therefore form the basis for judgments of necessity. Kant described his view as "transcendental idealism" because, although the Categories and Forms make possible objectively valid and necessary laws governing objects of experience, they cannot be ascribed to objects except insofar as those objects are experienced.

In experience, Kant rescued the traditional metaphysical distinction between form and matter: form is the a priori aspect of experience that mind imposes on matter in cognition. The inquiry into the nature of objects independent of experience by means of concepts, however, which Kant understood as the project of traditional metaphysics, cannot produce knowledge. However, Kant allowed that such inquiry, which he called "dialectic," is founded upon important human interests, such as the quest to understand practical freedom or to find purposiveness or systematic unity in nature.

Georg Hegel (1770–1831) held that ultimately only spirit is real. Hegel argued that history, in particular the history of human society, is a history of dialectical thought. Hegel, then, moved mind out of the individual altogether and eventually into an account of stages of human consciousness that are at once a kind of progression of reasoning, steps of psychological development, and social structures. Dialectic had a very different meaning for Hegel from that which Kant gave it. Hegel retained a focus on the process of reasoning that characterized Kant's dialectic and continued to consider the question of the invalidity of particular applications of a concept. The invalidity of a particular kind of reasoning is, however, of interest principally not because it makes a category mistake in applying concepts inappropriately but as itself a flawed way of being or experiencing objects in the world, which, because of its flaws, leads also to a particular new way of being.

The End of Metaphysics (1839–1980)

Kant himself rejected metaphysics, considered as an attempt to know objects outside experience. Forms of that position characterized three major recent philosophical movements that drew on his emphasis on the thinking self and his devotion to empiricism.

The Rejection of Metaphysics

[Pragmatism] will serve to show that almost every proposition of ontological metaphysics is either meaningless gibberish,—one word being defined by other words, and they by still others, without any real conception ever being reached,—or else is downright absurd. (Peirce, "What Pragmatism Is")

The fundamental faith of the metaphysicians is the faith in opposite values.… one may doubt, first, whether there are any opposites at all, and secondly whether these … opposite values … are not perhaps merely foreground estimates, only provisional perspectives, perhaps even from some nook, perhaps from below. (Nietzsche, section 2)

The non-theoretical character of metaphysics would not be in itself a defect.… the danger lies in the deceptive character of metaphysics; it gives the illusion of knowledge without actually giving any knowledge. This is why we reject it. (Carnap, "The Rejection of Metaphysics," from Philosophy and Logical Syntax, 1934, section 5)

American Pragmatism.

This movement emphasized, following Kant and in some cases Hegel, the role of concepts in experience. John Dewey (1859–1952) argued that concepts distort our understanding of the unity of nature. Charles Peirce (1839–1914) similarly took conceptual analysis to demonstrate that the propositions of traditional metaphysics are nonsensical. William James (1842–1910) defended the use of concepts and took metaphysics to be the task of understanding why people organize experience the way they do. Some traditional metaphysical notions remained in American Pragmatism. Peirce, for example, defended an account of generals, a theory of natural kinds. However, the movement was generally critical of traditional, a priori metaphysics.

Phenomenology and existentialism.

These movements, which started perhaps with the works of Nietzsche, emphasized the importance of perspective for undermining or perhaps reassessing metaphysics.

Phenomenology is the study of things as one experiences them. In Ideas, Edmund Husserl (1859–1938) argued that this project requires setting aside questions of existence, which amounts to making questions of metaphysics secondary to questions of experience. Martin Heidegger (1889–1976), slightly differently, made questions of existence, or being, just questions of experience. The study of being is not, for Heidegger, then, the study of the being of fundamental things in the universe that are independent of experience but instead the study of the being of things as they are experienced and, perhaps more important, formed and conceived by the thinker. Existentialism, perhaps best known from the works of Jean-Paul Sartre (1905–1980), in the most general terms is the conclusion, from either of these positions, that there are no metaphysical facts about the world, with the result that if one really needs such facts, as Kant suggested, one must either create them or insist upon what one has no claim to know.

Logical positivism.

Ludwig Wittgenstein (1889–1951) and Rudolf Carnap (1891–1970) derived, largely from Kant, the view that knowledge is only of objects of experience. Logical positivists held, furthermore, that as terms apply meaningfully only to objects of experience, metaphysical claims are not merely false or mistaken but nonsensical. The movement was largely responsible for making language and its meaning the focus of a great deal of recent philosophical inquiry in metaphysics and also in epistemology and ethics.

Twenty-First-Century Developments

It is difficult to predict the debates and positions for which the early twenty-first century era will be remembered. A result of the focus on language and meaning produced by logical positivism is perhaps that many important metaphysical debates at the beginning of the twenty-first century have centered not on the question of what existence is or is like generally but on the question of whether particular sorts of things exist. A response to the positivist challenge to ethics, for example, has been to claim that terms in ethics are meaningful in the sense that they refer to real, existing things in the world, good and evil. In modal metaphysics, questions about the meaningfulness of possibility have produced debates over the metaphysical status of possible worlds: are possibilities real, and if so, how are they different from actual existents? Finally, the mind-body problem, now recast as the question of the relationship between the mind and the brain, and the existence of general or natural kinds, often a problem for set theory, have remained hotly debated matters.

The tradition of phenomenology and existentialism has given way to the movements of structuralism and deconstructionism. Proponents of these methods might, like many phenomenologists, deny that they study anything like traditional metaphysics. Structuralists abstract from the genesis and subject of a particular kind of world or experience and analyze it as a product of thought, or text, without a thinker, who, it is argued, is irrelevant to meaning. Deconstructionism is the view that largely as a result of the fact that texts are created by thinkers, the relevant structures are binary and can be understood in terms of opposition within the structure. The aim of deconstruction is to show how, like the self and the world for Fichte, the opposed units in the structures depend upon one another.

See also Knowledge ; Philosophy ; Pragmatism .

bibliography

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Michael LeBuffe