Metaphysics

Plato and Aristotle (right), by Raphael (Stanza della Segnatura, Rome). Aristotle is regarded as the "father" of metaphysics.

Metaphysics ( Greek: μετά (meta) = "after", φυσικά (phisiká) = "those on nature", derived from the arrangement of Aristotle's works in antiquity) is the branch of philosophy concerned with explaining the nature of the most fundamental aspects of the world. It addresses questions such as: What is the nature of reality? Does the world exist outside the mind? What is the nature of objects, events, places? Is free will possible in a world governed by causal laws?

A central part of metaphysics is ontology, which is aims to understand which things exist. Ontology is, one might say, an attempt to determine what the most basic building blocks are out of which the rest of reality is constructed. Philosophers of different times have shown different levels of optimism with respect to how much ontology can accomplish. Plato, for instance, appears to have thought that it is capable of showing the existence of entities which are outside of the sensible world, but which play some key role in determining the nature of that world. Many philosophers in the 20th century, however, saw ontology as, at best, an attempt to understand the relations between a certain set of concepts we use, such as that of substance, property and relation.

It is important to distinguish the sense of 'metaphysics' employed by philosophers from a different sense it has acquired relatively recently: one associated with spirituality and world-transcending thought. Though the latter usage has its historical roots in the former, almost all contemporary metaphysicians cringe when they walk by the 'Metaphysics' section of bookstores.

Because it concerns itself with fundamental questions, nearly every major philosopher has devoted a certain amount of thought to metaphysics. This means, however, that a history of metaphysics would be little less than a history of all of philosophy. This article will therefore survey the issues that have most concerned metaphysicians throughout history. A list of historical figures especially worth considering is provided at the end.

Central questions of metaphysics

Mind and Matter

The nature of matter was a problem in its own right in early philosophy. Indeed, it was Aristotle who introduced the idea of matter in general to the Western world, adapting the term hyle which originally meant "lumber". Early debates centred on identifying a single underlying principle. Water was claimed by Thales, Air by Anaximenes, Apeiron (the Boundless) by Anaximander, Fire by Heraclitus. Democritus conceived an atomic theory many centuries before it became scientifically accepted.

Of course, empirical science is now looked to for insights into matter. The nature of the mind and its relation to the body has been seen as more of a problem as science has progressed in its mechanistic understanding of the brain and body. Proposed solutions often have ramifications about the nature of reality as a whole. René Descartes proposed substance dualism, a theory according to which mind and body are essentially quite different, with the mind having some of the attributes traditionally assigned to the soul, in the 17th century. This creates a conceptual puzzle about how the two interact (which has received some strange answers, such as occasionalism). Evidence of a close relationship between brain and mind, such as the Phineas Gage case, have made this form of dualism increasingly unpopular.

Another rather sweeping proposal to address the mind-body problem is idealism, in which the material is eliminated in favour of the mental. Idealists, such as Bishop Berkeley, claim that material objects do not exist unless perceived and only as perceptions. The "German idealists", such as Fichte, Hegel and Schopenhauer took Kant as their starting-point, although it is debatable how much of an idealist Kant himself was. Idealism is also a common theme in Eastern philosophy. Related ideas are panpsychism and panexperientialism which say everything has a mind rather than everything exists in a mind. Alfred North Whitehead was a 20th century exponent of this approach.

Idealism is a monistic theory, in which there is a single universal substance or principles. Neutral monism, associated in different forms with Baruch Spinoza and Bertrand Russell is a theory which seeks to be less extreme than idealism, and to avoid the problems of substance dualism. It claims that existence consists of as single substance, which in itself is neither mental nor physical, but is capable of mental and physical aspects or attributes — thus it implies a dual-aspect theory.

For the last 100 years, the dominant metaphysics has without a doubt been materialistic monism. Science has demonstrated many ways in which mind and brain interact, but the exact nature of the relationship is still open to debate. Type identity theory, token identity theory, functionalism, reductive physicalism, nonreductive physicalism, eliminative materialism, anomolous monism, property dualism, epiphenomenalism and emergence are just some of the candidates for a scientifically-informed account of the mind. (It should be noted that while many of these positions are dualisms, none of them are substance dualism).

Prominent recent philosophers of mind include David Armstrong, Ned Block, David Chalmers, Patricia and Paul Churchland, Donald Davidson, Daniel Dennett, Jerry Fodor, David Lewis, Hilary Putnam, John Smart and Ludwig Wittgenstein.

Objects and their properties

Further information: Problem of universals

The world seems to contain many individual things, both physical, like apples, and abstract such as the British constitution, Greek democracy, and the number "3." Such objects are called particulars. Now, consider two apples. There seem to be many ways in which those two apples are similar, they may be approximately the same size, or shape, or color. They are both fruit, etc. One might also say that the two apples seem to have some thing or things in common. Universals or Properties are said to be those things.

Metaphysicians working on questions about universals or particulars are interested in the nature of objects and their properties, and the relationship between the two. For instance, one might hold that properties are abstract objects, existing outside of space and time, to which particular objects bear special relations. Others maintain that what particulars are is a bundle or collection of properties (specifically, a bundle of properties they have).

Identity and change

For further information, see: Identity, and Philosophy of space and time

The Greeks took some extreme positions on the nature of change: Parmenides denied that change occurs at all, while Heracleitus thought change was ubiquitous — "you cannot step into the same river twice".

Identity, sometimes called Numerical Identity, is the relation that a "thing" bears to itself, and which no "thing" bears to anything other than itself (cf. sameness). According to Leibniz, if some object x is identical to some object y, then any property that x has, y will have as well. However, it seems, too, that objects can change over time. If one were to look at a tree one day, and the tree later lost a leaf, it would seem that one could still be looking at that same tree. Two rival theories to account for the relationship between change and identity are Perdurantism, which treats the tree as a series of tree-stages, and Endurantism which maintains that the tree — the same tree — is present at every stage in its history.

Space and time

A traditional realist position in ontology is that time and space have existence apart from the human mind. Idealists, including Kant claim that space and time are mental constructs used to organise perceptions, or are otherwise unreal.

Suppose that one is sitting at a table, with an apple in front of him or her; the apple exists in space and in time, but what does this statement indicate? Could it be said, for example, that space is like an invisible three-dimensional grid in which the apple is positioned? Suppose the apple, and all physical objects in the universe, were removed from existence entirely. Would space as an "invisible grid," still exist? René Descartes and Leibniz believed it would not, arguing that without physical objects, "space" would be meaningless because space is the framework upon which we understand how physical objects are related to each other. Newton, on the other hand, argued for an absolute "container" space. The pendulum swung back to relational space with Einstein and Ernst Mach.

While the absolute/relative debate, and the realism debate are equally applicable to time and space, time presents some special problems of its own. The flow of time has been denied in ancient times by Parmenides and more recently by J. M. E. McTaggart in his paper The Unreality of Time.

The direction of time, or time's arrow, is also a puzzle, although physics is now driving the debate rather than philosophy. It appears that fundamental laws are time-reversible and the arrow of time must be an "emergent" phenomenon, perhaps explained by thermodynamics.

Common-sense tells us that objects persist across time, that there is some sense in which you are the same person you were yesterday, in which the oak is the same as the acorn, in which you perhaps even can step into the same river twice. Philosophers have developed two rival theories for how this happens, called "endurantism" and "perdurantism". Broadly speaking, endurantists hold that a whole object exists at each moment of its history, and the same object exist at each moment. Perdurantists believe that objects 4-dimensional entities made up of a series of Temporal Parts like the frames of a movie.

Necessity and possibility

See also: Modal logic  and Modal realism

Metaphysicians investigate questions about the ways the world could have been. David Lewis, in "On the Plurality of Worlds," endorsed a view called Concrete Modal realism, according to which facts about how things could have been are made true by other concrete worlds, just like ours, in which things are different. Other philosophers, such as Gottfried Leibniz, have dealt with the idea of possible worlds as well. The idea of necessity is that any necessary fact is true across all possible worlds; that is, we could not imagine it to be otherwise. A possible fact is one that is true in some possible world, even if not in the actual world. For example, it is possible that cats could have had two tails, or that any particular apple could have not existed. By contrast, certain propositions seem necessarily true, such as analytic propositions, e.g. "All bachelors are unmarried." The particular example of analytic truth being necessary is not universally held among philosophers. A less controversial view might be that self-identity is necessary, as it seems fundamentally incoherent to claim that for any x, it is not identical to itself; this is known as the principle of contradiction. Aristotle describes the principle of contradiction, "It is impossible that the same quality should both belong and not belong to the same thing . . . This is the most certain of all principles . . . Wherefore they who demonstrate refer to this as an ultimate opinion. For it is by nature the source of all the other axioms."

Determinism and Free Will

See also: Determinism  and Free will

Determinism is the philosophical proposition that every event, including human cognition, decision and action, is causally determined by an unbroken chain of prior occurrences. It holds that no random, spontaneous, mysterious, or miraculous events occur. The principal consequence of the deterministic claim is that it poses a challenge to the existence of free will.

The problem of free will is the problem of whether rational agents exercise control over their own actions and decisions. Addressing this problem requires understanding the relation between freedom and causation, and determining whether or not the laws of nature are causally deterministic. Some philosophers, called Incompatibilists view determinism and free will as mutually exclusive. If they believe in determinism, they will therefore believe free will to be an illusion, a position known as Hard Determinism. Proponents range from Baruch Spinoza to Ted Honderich.

Others, labeled Compatibilists, (or Soft Determinists) believe that the two ideas can be coherently reconciled. Adherents of this view include Thomas Hobbes and many modern philosophers.

Incompatibilists who accept free will but reject determinism are called Libertarians — not to be confused with the political sense. Robert Kane is one of the few modern defenders of this theory.

It is a popular misconception that determinism necessarily entails that humanity or individual humans have no influence on the future and its events (a position known as Fatalism); However determinists believe that the level to which human beings have influence over their future, is itself dependent on present and past.

Criticisms of metaphysics

Though some metaphysical projects have no ambitions beyond conceptual analysis, others have, to varying degrees, attempted to make substantive claims about the nature of reality (Plato again being a prime example). But the very suggestion that philosophers are in a position to discover substantive conclusions about the fundamental aspects of reality has struck many thinkers of an empiricist bent as patently absurd. This most frequently takes form as a challenge to whether such metaphysical claims can be justified, but an important movement known as logical positivism denied that metaphysics claims could even be meaningful.

Criticisms of justification

The line of thought that has lead some philosophers to claim that metaphysical statements cannot be justified runs roughly as follows: (1) metaphysical statements are about the world, and (2) all we know about the world we learn through our senses. Yet, as metaphysicians themselves admit, (3) metaphysical claims cannot be justified merely on through our senses. Therefore, metaphysical claims cannot be justified. Such a sentiment is especially obvious in some of the writings of the Scottish philosopher David Hume:

"If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion".

- An Enquiry Concerning Human Understanding

The obvious premise for the metaphysician to reject in the above argument is (2), the claim that all we know about the world is based in our senses. Plato, for instance, held that prior to birth, we encountered more fundamental aspects of reality, and merely need sensory promptings to recall those aspects. Descartes held that God had imprinted certain basic ideas in our minds in creating us, and that we could draw substantive conclusions from those ideas.

Kant, while being sympathetic to the basic anti-metaphysical argument, only accepted a qualified form of premise (1), the claim that metaphysical statements are about the world. He held that some metaphysical claims (such as 'every change has a cause') are not about a world that is completely independent of us, but rather about how objects appear to us. Moreover, the way that objects appear to us is partially determined by features of our own minds, and it is by knowing about those features that we can be justified in substantive claims about how objects will appear to us.

Criticisms of meaningfulness

Logical positivism, a movement started in Vienna that held a strong following in Britain, advanced a strong form of 'verificationism,' the view that the only meaningful statements were those that could in principle be verified by some set of observations. The positivists intended to use this view, which has at least some intuitive appeal, to do away with a large portion of religious doctrine and metaphysical disputes.

Three important features of most substantive metaphysical statements, such as 'every event has a cause', are their universality, necessity and non-analyticity. In other words, they say that, with respect to entire group of things (e.g. events), that each member of that group cannot exist without having some feature (e.g. 'having a cause'), even though that feature wouldn't be mentioned in a fully adequate definition of the group. The most experiential observations can show us, however, is that some particular thing actually has some feature. No set of observations can establish any non-definitional property of everything in a group, so all metaphysical claims would fail the verificationist test.

While it enjoyed considerable popularity for a time, the positivist project was eventually abandoned, for it became apparent that core statements of scientific theories (e.g. the statement of universal gravitation) share some of the features of metaphysical statements, and so cannot be directly verified by observations. In the wake of positivism, their lessons were taken instead to show that metaphysical statements are not meaningless statements, but rather that they are generally not fallible, testable or provable statements (see Karl Popper).

Major metaphysicians

Peter Abelard Aristotle Thomas Aquinas St. Augustine Avicenna (Ibn Sina) George Berkeley Boethius

René Descartes Georg Wilhelm Friedrich Hegel Martin Heidegger Immanuel Kant Gottfried Leibniz John Locke Plato

Plotinus Willard Van Orman Quine Bertrand Russell Jean-Paul Sartre Arthur Schopenhauer John Duns Scotus Baruch Spinoza

References

ISBN links support NWE through referral fees

• Butchvarov, Panayot (1979). Being Qua Being: A Theory of Identity, Existence and Predication. Bloomington and London: Indiana University Press.
• Kant, I (1781). Critique of Pure Reason.
• Gale, Richard M. (2002). The Blackwell Guide to Metaphysics. Oxford: Blackwell.
• Lowe, E. J. (2002). A Survey of Metaphysics. Oxford: Oxford University Press.
• Loux, M. J. (2006). Metaphysics: A Contemporary Introduction (3rd ed.). London: Routledge.
• Kim, J. and Ernest Sosa Ed. (1999). Metaphysics: An Anthology. Blackwell Philosophy Anthologies.
• Kim, J. and Ernest Sosa, Ed. (2000). A Companion to Metaphysics. Malden Massachusetts, Blackwell, Publishers.

External links

• Aristotle's Metaphysics trans. by W. D. Ross
• Aristotle's Metaphysics trans. by Hugh Tredennick (HTML at Perseus)
• Aristotle's Metaphysics at Stanford Encyclopedia of Philosophy
• Hume's Enquiry Concerning Human Understanding: Mirrored at eBooks@Adelaide
• E-text (The Norman Kemp Smith translation of Kant's Critique of Pure Reason)
• March of Metaphysics Historical overview orientated to Process thought
• Stanford Encyclopedia of Philosophy on metaphysics, by Peter Van Inwagen
• Metaphysics: Multiple Meanings A page that succinctly differentiates between various uses of the term "metaphysics."

Credits

New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:

• Metaphysics  ^history

The history of this article since it was imported to New World Encyclopedia:

• History of "Metaphysics"

Note: Some restrictions may apply to use of individual images which are separately licensed.