Thursday 6 September 2007

Natural science

From Wikipedia, the free encyclopedia


The Michelson–Morley experiment was used to disprove that light propagated through a luminiferous aether. This 19th century concept was then superseded by Albert Einstein's special theory of relativity.
The Michelson–Morley experiment was used to disprove that light propagated through a luminiferous aether. This 19th century concept was then superseded by Albert Einstein's special theory of relativity.

In science, the term natural science refers to a rational approach to the study of the universe, which is understood as obeying rules or laws of natural origin. The term natural science is also used to distinguish those fields that use the scientific method to study nature from the social sciences, which use the scientific method to study human behavior and society, and from the formal sciences, such as mathematics and logic, which use a different methodology.

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Overview

Natural sciences form the basis for the applied sciences. Together, the natural and applied sciences are distinguished from the social sciences on the one hand, and from the humanities, theology and the arts on the other. Mathematics, statistics and computer science are not considered natural sciences, but provide many tools and frameworks used within the natural sciences.

Alongside this traditional usage, the phrase natural sciences is also sometimes used more narrowly to refer to its everyday usage, that is, related to natural history. In this sense "natural sciences" may refer to the biological sciences and perhaps also the earth sciences, as distinguished from the physical sciences, including astronomy, physics, and chemistry.

Within the natural sciences, the term hard science is sometimes used to describe those sub-fields that rely on experimental, quantifiable data or the scientific method and focus on accuracy and objectivity. These usually include physics, chemistry and many of the sub-fields of biology. By contrast, soft science is often used to describe the scientific fields that are more reliant on qualitiative research, including the social sciences.

History

Prior to the 17th century, the objective study of nature was known as natural philosophy. Over the next two centuries, however, a philosophical interpretation of nature was gradually replaced by a scientific approach using inductive methodology. The works of Sir Francis Bacon popularized this approach, thereby helping to forge the scientific revolution.

By the 19th century the study of science had come into the purview of professionals and institutions, and in so doing it gradually acquired the more modern name of natural science. The term scientist was coined by William Whewell in an 1834 review of Mary Somerville's On the Connexion of the Sciences. However the word did not enter general use until nearly the end of the same century.

According to a famous 1923 textbook Thermodynamics – and the Free Energy of Chemical Substances by the American chemist Gilbert N. Lewis and the American physical chemist Merle Randall, the natural sciences contain three great branches:

Aside from the logical and mathematical sciences, there are three great branches of natural science which stand apart by reason of the variety of far reaching deductions drawn from a small number of primary postulates – they are the mechanics, electrodynamics, and thermodynamics.

[edit] Disciplines of natural sciences

[edit] Astronomy

Main article: Astronomy
Space missions have been used to image distant locations within the Solar System, such as this Apollo 11 view of Daedalus crater on the far side of the Moon.
Space missions have been used to image distant locations within the Solar System, such as this Apollo 11 view of Daedalus crater on the far side of the Moon.

This discipline is the science of celestial objects and phenomena that originate outside the Earth's atmosphere. It is concerned with the evolution, physics, chemistry, meteorology, and motion of celestial objects, as well as the formation and development of the universe. Astronomy includes the examination, study and modeling of stars, planets, comets, galaxies and the cosmos. Most of the information used by astronomers is gathered by remote observation, although some laboratory reproduction of celestial phenomenon has been performed (such as the molecular chemistry of the interstellar medium.)

While the origins of the study of celestial features and phenomenon can be traced back to antiquity, the scientific methodology of this field began to develop in the middle of the seventeenth century. A key factor was Galileo's introduction of the telescope to examine the night sky in more detail. The mathematical treatment of astronomy began with Newton's development of celestial mechanics and the laws of gravitation, although it was triggered by earlier work of astronomers such as Kepler. By the nineteenth century, astronomy had developed into a formal science with the introduction of instruments such as the spectroscope and photography, along with much improved telescopes and the creation of professional observatories.

A fragment of DNA, the chemical sequence that contains genetic instructions for the development and functioning of living organisms.
A fragment of DNA, the chemical sequence that contains genetic instructions for the development and functioning of living organisms.

Biology

Main article: Biology

This field encompasses a set of disciplines that examines phenomena related to living organisms. The scale of study can range from sub-component biophysics up to complex ecologies. Biology is concerned with the characteristics, classification and behaviors of organisms, as well as how species were formed and their interactions with each other and the natural environment.

The biological fields of botany, zoology, and medicine date back to early periods of civilization, while microbiology was introduced in the 17th century with the invention of the microscope. However it was not until the 19th century that biology became a unified science; once scientists discovered commonalities between all living things it was decided they were best studied as a whole. Some key developments in the science of biology were the discovery of genetics; Darwin's theory of evolution through natural selection; the germ theory of disease and the application of the techniques of chemistry and physics at the level of the cell or organic molecule.

Modern Biology is divided into sub-disciplines by the type of organism and by the scale being studied. Molecular biology is the study of the fundamental chemistry of life, while cellular biology is the examination of the cell; the basic building block of all life. At a higher level, Physiology looks at the internal structure of organism, while ecology looks at how various organisms interrelate.

Chemistry

Main article: Chemistry
This structural formula for molecule caffeine shows a graphical representation of how the atoms are arranged.
This structural formula for molecule caffeine shows a graphical representation of how the atoms are arranged.

Constituting the scientific study of matter at the atomic and molecular scale, chemistry deals primarily with collections of atoms, such as gases, molecules, crystals, and metals. The composition, statistical properties, transformations and reactions of these materials are studied. Chemistry also involves understanding the properties and interactions of individual atoms for use in larger-scale applications. Most chemical processes can be studied directly in a laboratory, using a series of (often well-tested) techniques for manipulating materials, as well as an understanding of the underlying processes. Chemistry is often called "the central science" because of its role in connecting the other natural sciences.

Early experiments in chemistry had their roots in the system of Alchemy, a set of beliefs combining mysticism with physical experiments. The science of chemistry began to develop with the work of Robert Boyle, the discoverer of gas, and Antoine Lavoisier, who developed the theory of the Conservation of mass. The discovery of the chemical elements and the concept of Atomic Theory began to systematize this science, and researchers developed a fundamental understanding of states of matter, ions, chemical bonds and chemical reactions. The success of this science led to a complementary chemical industry that now plays a significant role in the world economy.

[edit] Earth science

Main article: Earth science

Earth science (also known as geoscience, the geosciences or the Earth Sciences), is an all-embracing term for the sciences related to the planet Earth, including geology, geophysics, hydrology, meteorology, physical geography, oceanography, and soil science.

[edit] Physics

Main article: Physics
This free body diagram illustrates the different forces acting on a projectile.
This free body diagram illustrates the different forces acting on a projectile.

Physics embodies the study of the fundamental constituents of the universe, the forces and interactions they exert on one another, and the results produced by these interactions. In general, the physics is regarded as the fundamental science as all other natural sciences utilize and obey the principles and laws set down by the field. Physics relies heavily on mathematics as the logical framework for formulation and quantification of principles.

The study of the principles of the universe has a long history and largely derives from direct observation and experimentation. The formulation of theories about the governing laws of the universe has been central to the study of physics from very early on, with philosophy gradually yielding to systematic, quantitative experimental testing and observation as the source of verification. Key historical developments in physics include Isaac Newton's theory of universal gravitation and classical mechanics, an understanding of electricity and it's relation to magnetism, Einstein's theories of special and general relativity, the development of thermodynamics, and the quantum mechanical model of atomic and subatomic physics.

The field of physics is extremely broad, and can include such diverse studies as quantum mechanics and theoretical physics to applied physics and optics. Modern physics is becoming increasingly specialized, where researchers tend to focus on a particular area rather than being "universalists" like Albert Einstein and Lev Landau, who worked in multiple areas.

Cross-disciplines

The distinctions between the natural science disciplines is not always sharp, and they share a number of cross-discipline fields. Physics plays a significant role in the other natural sciences, as represented by astrophysics, geophysics, physical chemistry and biophysics. Likewise chemistry is represented by such fields as biochemistry and astrochemistry.

A particular example of a scientific discipline that draws upon multiple natural sciences is Environmental science. This field studies the interactions of physical, chemical and biological components of the environment, with a particular regard to the effect of human activities and the impact on biodiversity and sustainability. This science also draws upon expertise from other fields such as economics, law and social sciences.

Natural philosophy


From Wikipedia, the free encyclopedia


Natural philosophy or the philosophy of nature, known in Latin as philosophia naturalis, is a term applied to the objective study of nature and the physical universe that was regnant before the development of modern science. It is considered the counterpart, or to positivists the precursor, of what is now called natural science, especially physics.

Forms of science historically developed out of philosophy or more specifically natural philosophy. At older universities, long-established Chairs of Natural Philosophy are nowadays occupied mainly by physics professors. Modern notions of science and scientists date only to the 19th century. Before then, the word "science" simply meant knowledge and the label of scientist did not exist. Isaac Newton's 1687 scientific treatise is known as The Mathematical Principles of Natural Philosophy.

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[edit] Origin and evolution of the term

Natural philosophy was the term whose usage preceded our current term science in the sense that prior to the replacement of the term natural philosophy with the term science, the term science was used exclusively as a synonym for knowledge or study and when the subject of that knowledge or study was 'the workings of nature', then the term natural philosophy would be used. Natural philosophy became science (scientia in Latin, which means "knowledge") when knowledge acquisition through experiments (special experiences) regulated by the scientific method became its own specialized branch over and above the analysis and synthesis of experiences of which philosophy partakes. More specifically, in the 18th and 19th centuries, natural philosophy referred to what is now called physical science. From the mid-19th century, when it became increasingly unusual for scientists to contribute to both physics and chemistry, it just meant physics, and is still used in that sense in degree titles at Oxford University. Natural philosophy was distinguished from the other pre-cursor of modern science, Natural history, in that the former involved reasoning about nature (and after Galileo, quantitative reasoning), whereas the latter was essentially qualitative and descriptive.

[edit] Scope of natural philosophy

In what is thought to be one of Plato's earliest dialogues, Charmides, the distinction is drawn between sciences or bodies of knowledge which produce a physical result, and those which do not. Natural philosophy has been categorized as a theoretical rather than a practical branch of philosophy (like ethics). Sciences that guide arts and which draw upon the philosophical knowledge of nature can of course produce many practical results, but these subsidiary sciences (e.g. architecture or medicine) are considered to go beyond natural philosophy.

The study of natural philosophy presupposes that change is a reality. Although this may seem obvious, there have been some philosophers who have denied change, such as Plato's teacher Parmenides and later Greek philosopher Sextus Empiricus and perhaps some Eastern philosophers as well. George Santayana in his Scepticism and Animal Faith attempted to show that the reality of change cannot be proven. If this is true, the soundness of physics is based on our ability to trust our senses.

In René Descartes' metaphysical system of dualism, there are two kinds of substance: matter and mind. According to this system, everything which is "matter" is deterministic and natural—and so belongs to natural philosophy—and everything which is "mind" is volitional and non-natural, and falls outside the domain of philosophy of nature.

[edit] Branches and subject matter of natural philosophy

Major branches of natural philosophy include astronomy and cosmology, the study of nature on the grand scale; etiology, the study of (intrinsic and sometimes extrinsic) causes; the study of chance, probability and randomness; the study of elements; the study of the infinite and the unlimited (virtual or actual); the study of matter; mechanics, the study of translation of motion and change; the study of nature or the various sources of actions; the study of natural qualities; the study of physical quantities; the study of relations between physical entities; and the philosophy of space and time. (Adler, 1993)

[edit] Figures in natural philosophy

While proposals for a much more 'inquisitive' and practical approach to the study of nature originated with Francis Bacon, Robert Boyle wrote what is considered to be a seminal work on the distinction between nature and metaphysics called A Free Enquiry into the Vulgarly Received Notion of Nature. This book, written in 1686, marked the point where the scene was set for natural philosophy to turn into science. It represented a radical departure from the scholasticism of the Middle Ages, and while features of natural philosophy retained some of the trappings of the elitism associated with its precursor, natural philosophy was arguably empirical while previous attempts to describe nature were not. An important distinguishing characteristic of science and natural philosophy is the fact that natural philosophers generally did not feel compelled to test their ideas in a practical way. Instead, they observed phenomena and came up with 'philosophical' conclusions.

Boyle, while he is the first to fully embrace such an approach in both his experimental endeavours and his writings, shares with Bacon (and Galileo who was the inspiration in these matters for both Bacon and Boyle) a conviction that practical experimental observation was the key to a more satisfactory understanding of nature than would have otherwise been sought through either exclusive reference to received authority or a purely speculative approach.

Although Galileo's 'natural philosophy' is hardly distinguishable from science in many ways, the connection between his experiments and his writings about them is characteristically philosophical, rather than being cluttered with the results of meticulously recorded observational detail of practical scientific research, in the way that Boyle subsequently advocated.

Even though Boyle described what he practiced as 'natural philosophy', the very innovations that Boyle introduced can be seen as a basis for delineating a transition from proto-science to science. Among these innovations are an insistence upon the publication of detailed experimental results, including the results of unsuccessful experiments; and also a requirement for the replication of experiments as a means of validating observational claims.

Thus Boyle's application of the term 'natural philosophy' to his own work may be regarded an anachronistic conflation with earlier proto-science, since the distinction between the terms 'natural philosophy' and 'science' only arose after Boyle's passing.

Boyle would therefore describe his work as 'natural philosophy', whereas we would describe it as 'science'; and yet Boyle's use was correct for his own time. Nonetheless, he is in many ways the architect of the modern distinction between the two terms.

The ancient emphasis on deduction has its representative in Aristotle's Organum, and the new emphasis on induction and research has its representative in Francis Bacon's treatise Novum Organum.

[edit] Revival

In the context of the creation-evolution controversy the term has been revived (or, some would claim, appropriated) by proponents of creationism, creation science, and intelligent design concerned that modern science does not accept supernatural explanations.[citation needed] Some such proponents put forward supernatural explanations as superior to natural ones. Some offer a critique of modern science.

[edit] References in Popular Culture

The writer Nat Hillard maintains a weekly column for the Stanford Daily newspaper entitled "Nat-ural Philosophy".

[edit] References

Adler, Mortimer J. (1993). The Four Dimensions of Philosophy: Metaphysical, Moral, Objective, Categorical. Macmillan. ISBN 0-02-500574-X.

Philip Kitcher, Science, Truth, and Democracy. Oxford Studies in Philosophy of Science. Oxford; New York: Oxford University Press, 2001. LCCN:2001036144 ISBN 0-19-514583-6

Bertrand Russell, A History of Western Philosophy and Its Connection with Political and Social Circumstances from the Earliest Times to the Present Day (1945) Simon & Schuster, 1972. [1]

Santayana, George (1923). Scepticism and Animal Faith. Dover Publications, 27-41. ISBN 0-486-20236-4.

David Snoke, Natural Philosophy: A Survey of Physics and Western Thought. Access Research Network, 2003. ISBN 1-931796-25-4.[2] [3] [4] [5] A textbook on physics as natural philosophy grounded in Christian theology and biblical study.

Metaphysics


From Wikipedia, the free encyclopedia



Plato (Left) and Aristotle (right), by Raphael (Stanza della Segnatura, Rome)

Metaphysics is the branch of philosophy that investigates principles of reality transcending those of any particular science, traditionally including cosmology and ontology. It is also concerned with explaining the ultimate nature of being and the world.[1] Its name derives from the Greek words μετά (metá) (meaning "after") and φυσικά (physiká) (meaning "after talking about physics"), "physics" referring to those works on matter by Aristotle in antiquity.[2] In english, though, "meta" means "beyond;over;transcending". Therefore, metaphysics is the study of that which transcends physics. Many philosophers such as Immanuel Kant would later argue that certain questions concerning metaphysics (notably those surrounding the existence of God, soul and freedom) are inherent to human nature and have always intrigued mankind. Some examples are:

  • What is the nature of reality?
  • Why does the world exist, and what is its origin or source of creation?
  • Does the world exist outside the mind?
  • If things exist, what is their objective nature?

A central branch of metaphysics is ontology, the investigation into what types of things there are in the world and what relations these things bear to one another. The metaphysician also attempts to clarify the notions by which people understand the world, including existence, objecthood, property, space, time, causality, and possibility.

More recently, the term "metaphysics" has also been used more loosely to refer to "subjects that are beyond the physical world". A "metaphysical bookstore", for instance, is not one that sells books on ontology, but rather one that sells books on spirits, faith healing, crystal power, occultism, and other such topics.

Before the development of modern science, scientific questions were addressed as a part of metaphysics known as "natural philosophy"; the term "science" itself meant "knowledge". The Scientific Revolution, however, made natural philosophy an empirical and experimental activity unlike the rest of philosophy, and by the end of the eighteenth century it had begun to be called "science" in order to distinguish it from philosophy. Metaphysics therefore became the philosophical enquiry into subjects beyond the physical world. Natural philosophy and science may still be considered topics of metaphysics, if the definition of "metaphysics" includes empirical explanations.

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[edit] History of metaphysics

One of the founders of metaphysics is Parmenides of Elea. He held that the multiplicity of existing things, their changing forms and motion, are but an appearance of a single eternal reality (“Being”), thus giving rise to the Parmenidean principle that “all is one.” From this concept of Being, he went on to say that all claims of change or of non-Being are illogical. Because he introduced the method of basing claims about appearances on a logical concept of Being, he is considered one of the founders of metaphysics. [3]

Referred to as the subject of "first philosophy", the term "metaphysics" is utilized in the works of Aristotle. The editor of his works, Andronicus of Rhodes, placed the books on first philosophy right after another work, Physics, and called these books τα μετα τα φυσικά βιβλια (ta meta ta physika biblia) or, "the books that come after the [books on] physics." This was misread by Latin scholiasts, who thought it meant "the science of what is beyond the physical."[citation needed] In the English language, the word comes by way of the Medieval Latin metaphysica, the neuter plural of Medieval Greek metaphysika.[4] While its Greek and Latin origins are clear, various dictionaries trace its first appearance in English to the mid-sixteenth century, although in some cases as early as 1387.[4][5]

Aristotle's Metaphysics was divided into three parts, in addition to some smaller sections related to a philosophical lexicon and some reprinted extracts from the Physics, which are now regarded as the proper branches of traditional Western metaphysics:

Ontology
The study of Being and existence; includes the definition and classification of entities, physical or mental, the nature of their properties, and the nature of change.
Theology
The study of God; involves many topics, including among others the nature of religion and the world, existence of the divine, questions about Creation, and the numerous religious or spiritual issues that concern humankind in general.
Universal science
The study of first principles, which Aristotle believed to be the foundation of all other inquiries. An example of such a principle is the law of noncontradiction and the status it holds in non-paraconsistent logics.

Universal science or first philosophy treats of "being qua being" — that is, what is basic to all science before one adds the particular details of any one science. Essentially "being qua being" may be translated as "being insofar as being goes", or as, "being in terms of being". This includes topics such as causality, substance, species and elements, as well as the notions of relation, interaction, and finitude.

Metaphysics as a discipline was a central part of academic inquiry and scholarly education even before the age of Aristotle. Long considered "the Queen of Sciences",[cite this quote] its issues were considered no less important than the other main formal subjects of physical science, medicine, mathematics, poetics and music. Since the beginning of modern philosophy during the seventeenth century, problems that were not originally considered within the bounds of metaphysical have been added to its purview, while other problems considered metaphysical for centuries are now typically relegated to their own separate regions in philosophy, such as philosophy of religion, philosophy of mind, philosophy of perception, philosophy of language, and philosophy of science.

In some cases, subjects of metaphysical scholarship have been found to be entirely physical and natural, thus making them part of physics proper (cf. Albert Einstein's Theory of Relativity).

[edit] Central questions of metaphysics

Most positions that can be taken with regards to any of the following questions are endorsed by one or another notable philosopher. It is often difficult to frame the questions in a non-controversial manner.

[edit] Mind and matter

See also: Matter, Materialism, and Philosophy of mind

The nature of matter was a problem in its own right in early philosophy. Aristotle himself introduced the idea of matter in general to the Western world, adapting the term hyle which originally meant "lumber". Early debates centered 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 was accepted by modern science.

Philosophers now look to empirical science for insights into the nature of 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 in which mind and body are essentially quite different, with the mind having some of the attributes traditionally assigned to the soul, in the seventeenth 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 proposal discussing the mind-body problem is idealism, in which the material is sweepingly eliminated in favor of the mental. Idealists, such as George 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 twentieth-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 a 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 one hundred 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, Thomas Nagel, Hilary Putnam, John Searle, John Smart and Ludwig Wittgenstein.

[edit] 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 love, 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).

[edit] Identity and change

Main article: Identity and change
See also: Identity (philosophy) 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: "[Y]ou 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.

[edit] Space and time

See also: Philosophy of space and time and Spacetime

In the Middle Ages, Saint Augustine of Hyppo asked the fundamental question about the nature of 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, also known as "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 a statistical understanding of thermodynamic entropy.

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 exists at each moment. Perdurantists believe that objects are four-dimensional entities made up of a series of temporal parts like the frames of a movie.

[edit] Religion and spirituality

Theology is the study of God and the Nature of the Divine. Is there a God (monotheism), many Gods (polytheism) or no Gods (atheism)? Does the Divine intervene directly in the world (theism), or is its sole function to be the first cause of the universe (deism)? Are God and the World different (panentheism, dualism) or are they identical (pantheism)? These are the primary metaphysical questions concerning theologians.[citation needed]

Within the standard Western philosophical tradition, theology reached its peak under the medieval school of thought known as scholasticism, which focused primarily on the metaphysical aspects of Christianity. While the work of the scholastics has been largely eclipsed in the wake of modern philosophy, key figures such as Thomas Aquinas still play an important role in the philosophy of religion.[citation needed]

[edit] 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."

[edit] Abstract objects and mathematics

See also: Nominalism, Platonism, and Philosophy of mathematics

Some philosophers endorse views according to which there are abstract objects such as numbers, or Universals. (Universals are properties that can be instantiated by multiple objects, such as redness or squareness.) Abstract objects are generally regarded as being outside of space and time, and/or as being causally inert. Mathematical objects and fictional entities and worlds are often given as examples of abstract objects. The view that there really are no abstract objects is called nominalism. Realism about such objects is exemplified by Platonism. Other positions include moderate realism, as espoused by Aristotle, and conceptualism.

The philosophy of mathematics overlaps with metaphysics because some positions are realistic in the sense that they hold that mathematical objects really exist, whether transcendentally, physically, or mentally. Platonic realism holds that mathematical entities are a transcendent realm of non-physical objects. The simplest form of mathematical empiricism claims that mathematical objects are just ordinary physical objects, i.e. that squares and the like physically exist. Plato rejected this view, among other reasons, because geometrical figures in mathematics have a perfection that no physical instantiation can capture. Modern mathematicians have developed many strange and complex mathematical structures with no counterparts in observable reality, further undermining this view. The third main form of realism holds that mathematical entities exist in the mind. However, given a materialistic conception of the mind, it does not have the capacity to literally contain the many infinities of objects in mathematics. Intuitionism, inspired by Kant, sticks with the idea that "there are no non-experienced mathematical truths". This involves rejecting as intuitionistically unacceptable anything that cannot be held in the mind or explicitly constructed. Intuitionists reject the law of the excluded middle and are suspicious of infinity, particularly of transfinite numbers.

Other positions such as formalism and fictionalism that do not attribute any existence to mathematical entities are anti-realist.

[edit] 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 the laws of nature are causally deterministic. Some philosophers, known as 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, a term 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). Determinists, however, believe that the level to which human beings have influence over their future is itself dependent on present and past.

[edit] Cosmology and cosmogony

See also: Cosmology (metaphysics)

Cosmology is the branch of metaphysics that deals with the world as the totality of all phenomena in space and time. Historically, it has had quite a broad scope, and in many cases was founded in religion. The ancient Greeks did not draw a distinction between this use and their model for the cosmos. However, in modern use it addresses questions about the Universe which are beyond the scope of science. It is distinguished from religious cosmology in that it approaches these questions using philosophical methods (e.g. dialectics). Cosmogony deals specifically with the origin of the universe.

Modern metaphysical cosmology and cosmogony try to address questions such as:

[edit] Criticism

Metaphysics has been attacked, at different times in history, as being futile and overly vague. David Hume went so far as to write:

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

Immanuel Kant prescribed a limited role to the subject and argued against knowledge progressing beyond the world of our representations, except to knowledge that the noumena exist:

...though we cannot know these objects as things in themselves, we must yet be in a position at least to think them as things in themselves; otherwise we should be landed in the absurd conclusion that there can be appearance without anything that appears.

Critique of Pure Reason pp. Bxxvi-xxvii

A.J. Ayer is famous for leading a "revolt against metaphysics," where he claimed that its propositions were meaningless in his book "Language, Truth and Logic". Ayer was a defender of verifiability theory of meaning. British universities became less concerned with the area for much of the mid 20th century. However, metaphysics has seen a reemergence in recent times amongst philosophy departments. Mostly due to the failure of verificationism.

A more nuanced view is that metaphysical statements are not meaningless statements, but rather that they are generally not fallible, testable or provable statements (see Karl Popper). That is to say, there is no valid set of empirical observations nor a valid set of logical arguments, which could definitively prove metaphysical statements to be true or false. Hence, a metaphysical statement usually implies an idea about the world or about the universe, which may seem reasonable but is ultimately not empirically verifiable. That idea could be changed in a non-arbitrary way, based on experience or argument, yet there exists no evidence or argument so compelling that it could rationally force a change in that idea, in the sense of definitely proving it false.

[edit] Disciplines, topics and problems

Disciplines


Topics and problems




[edit] Notable metaphysicians