Science is a body of
empirical,
theoretical, and
practical knowledge about the
natural world, produced by a global community of researchers making use of
scientific methods, which emphasize the observation,
experimentation and
explanation of real world
phenomena. Given the dual status of science as
objective knowledge and as a human construct, good
historiography of science draws on the
historical methods of both
intellectual history and
social history.
Tracing the exact origins of modern science is difficult. This is due in large part to the scant documentary and physical evidence of ancient investigations of nature. Even the word
scientist is relatively recent -- first coined by
William Whewell in the 19th century. Previously, people investigating nature called themselves
natural philosophers.
While
empirical investigations of the natural world have been described since
antiquity (for example, by
Aristotle), and
scientific methods have been employed since the
Middle Ages (for example, by
Ibn al-Haytham), modern science wasn't fully developed until the
early modern period, during what is known as the
Scientific Revolution of the 16th and 17th centuries.
Scientific methods are considered to be so fundamental to modern science that some — especially
philosophers of science and practicing scientists — consider earlier inquiries into nature to be
pre-scientific. Traditionally, historians of science have defined science sufficiently broadly to include those inquiries.
As an academic field,
history of science began with the publication of
William Whewell's
History of the Inductive Sciences (first published in 1837). A more formal study of the history of science as an independent discipline was launched by
George Sarton's publications,
Introduction to the History of Science (published in 1927) and the
Isis journal (founded in 1912). The
history of mathematics,
history of technology, and
history of philosophy are distinct areas of research and are covered in other articles. Mathematics is closely related to but distinct from natural science (at least in the modern conception). Technology is likewise closely related to but clearly differs from the search for empirical truth. Philosophy differs from science in its engagement in
analysis and
normative discourse, among other differences. In practice science, mathematics, technology, and philosophy are obviously deeply entwined, and clear lines demarcating them are not evident until the 19th century (when science first became
professionalized). History of science has therefore been deeply informed by the histories of mathematics, technology, and philosophy -- even as those fields have become increasingly autonomous.
Theories and sociology of the history of science
Much of the study of the history of science has been devoted to answering questions about what science
is, how it
functions, and whether it exhibits large-scale patterns and trends. The
sociology of science in particular has focused on the ways in which scientists work, looking closely at the ways in which they "produce" and "construct" scientific knowledge. Since the 1960s, a common trend in
science studies (the study of the sociology and history of science) has been to emphasize the "human component" of scientific knowledge, and to de-emphasize the view that scientific data are self-evident, value-free, and context-free.
A major subject of concern and controversy in the
philosophy of science has been the nature of
theory change in science.
Karl Popper argued that scientific knowledge is progressive and cumulative;
Thomas Kuhn, that scientific knowledge moves through "
paradigm shifts" and isn't necessarily progressive; and
Paul Feyerabend, that scientific knowledge isn't cumulative or progressive and that there can be no
demarcation in terms of method between science and any other form of investigation.
Since the publication of Kuhn's
The Structure of Scientific Revolutions in 1962, historians, sociologists, and philosophers of science have debated the meaning and objectivity of science. Often, but not always, a conflict over the "truth" of science has split along the lines of philosophers and natural scientists on the one hand and historians and social scientists on the other (see the "
Science Wars").
Early cultures
In prehistoric times, advice and knowledge was passed from generation to generation in an
oral tradition. The development of writing enabled knowledge to be stored and communicated across generations with much greater fidelity. Combined with the
development of agriculture, which allowed for a surplus of food, it became possible for early civilizations to develop, because more time could be devoted to tasks other than survival.
Many ancient civilizations collected astronomical information in a systematic manner through simple observation. Though they'd no knowledge of the real physical structure of the planets and stars, many theoretical explanations were proposed. Basic facts about human physiology were known in some places, and
alchemy was practiced in several civilizations. Considerable observation of macrobiotic flora and fauna was also performed.
Science in the Fertile Crescent
From their beginnings in
Sumer (now
Iraq) around
3500 BC the
Mesopotamian peoples began to attempt to record some
observations of the world with extremely thorough
quantitative and
numerical data. But their observations and measurements were seemingly taken for purposes other than for
scientific laws. A concrete instance of
Pythagoras' law was recorded, as early as the
18th century BC: the Mesopotamian cuneiform tablet
Plimpton 322 records a number of Pythagorean triplets (3,4,5) (5,12,13). ..., dated 1900 BC, possibly millennia before Pythagoras,
(External Link
) but an abstract formulation of the Pythagorean theorem was not.
Significant advances in
Ancient Egypt include astronomy, mathematics and medicine. Their
geometry was a necessary outgrowth of
surveying to preserve the layout and ownership of farmland, which was flooded annually by the
Nile river. The 3,4,5
right triangle and other rules of thumb served to represent rectilinear structures, and the post and lintel architecture of Egypt. Egypt was also a center of
alchemy research for much of the
Mediterranean.
Science in the Hellenic world
In
Antiquity, the inquiry into the workings of the universe took place both in investigations aimed at such practical goals as establishing a reliable calendar or determining how to cure a variety of illnesses and in those abstract investigations known as
natural philosophy. The ancient peoples who are considered the first
scientists may have thought of themselves as
natural philosophers, as practitioners of a skilled profession (for example, physicians), or as followers of a religious tradition (for example, temple healers).
The earliest Greek philosophers, known as the
pre-Socratics, provided competing answers to the question found in the myths of their neighbors: "How did the ordered
cosmos in which we live come to be?" Subsequently, Plato and Aristotle produced the first systematic discussions of natural philosophy, which did much to shape later investigations into nature.
The important legacy of this period included substantial advances in factual knowledge, especially in anatomy, zoology, and astronomy; an awareness of the importance of certain scientific problems, especially those related to the problem of change and its causes; and a recognition of the methodological importance of applying mathematics to natural phenomena and of undertaking empirical research.
Science in India
Indian philosophers in
ancient India developed
atomic theories, which included formulating ideas about the
atom in a systematic manner and propounding ideas about the atomic constitution of the material world. The
principle of relativity was also available in an early embryonic form in the Indian philosophical concept of "
sapekshavad". The literal translation of this
Sanskrit word is "
theory of relativity" (not to be confused with Einstein's
theory of relativity). The
wootz,
crucible and
stainless steels were invented in India, and were widely exported, resulting in "
Damascus steel" by the year 1000.
The mathematician-astronomer
Aryabhata (476-550), in his
Aryabhatiya (499) and
Aryabhata Siddhanta, worked out an accurate
heliocentric model of
gravitation, including
elliptical orbits, the
circumference of the
earth, and the longitudes of planets around the Sun. He also introduced a number of
trigonometric functions (including
sine,
versine,
cosine and inverse sine),
trigonometric tables, and techniques and
algorithms of
algebra. In the 7th century,
Brahmagupta briefly described the
law of gravitation, and recognized
gravity as a force of attraction. He also lucidly explained the use of
zero as both a
placeholder and a
decimal digit, along with the
Hindu-Arabic numeral system now used universally throughout the world.
Arabic translations of the two astronomers' texts were soon available in the
Islamic world, introducing what would become
Arabic numerals to the Islamic World by the 9th century.
The first 12 chapters of the
Siddhanta Shiromani, written by
Bhāskara in the 12th century, cover topics such as: mean longitudes of the planets; true longitudes of the planets; the three problems of diurnal rotation; syzygies; lunar eclipses; solar eclipses; latitudes of the planets; risings and settings; the moon's crescent; conjunctions of the planets with each other; conjunctions of the planets with the fixed stars; and the patas of the sun and moon. The 13 chapters of the second part cover the nature of the sphere, as well as significant astronomical and trigometric calculations based on it.
During the 14th-16th centuries, the
Kerala school of astronomy and mathematics made significant advances in astronomy and especially mathematics, including fields such as
trigonometry and
calculus. In particular,
Madhava of Sangamagrama is considered the "founder of
mathematical analysis".
Science in China
China has a long and rich history of technological contribution. The so-called '
Four Great Inventions of ancient China' (
Chinese: 四大發明;
Pinyin: Sì dà fā míng) are the
compass,
gunpowder,
papermaking, and
printing. These four discoveries had an enormous impact on the development of
Chinese civilization and a far-ranging global impact. According to
English philosopher Francis Bacon, writing in
Novum Organum,
There are many notable contributors to the field of Chinese science throughout the ages. One of the best examples would be
Shen Kuo (1031–1095), a
polymath scientist and statesman who was the first to describe the
magnetic-needle
compass used for
navigation, discovered the concept of
true north, improved the design of the astronomical
gnomon,
armillary sphere,
sight tube, and
clepsydra, and described the use of
drydocks to repair boats. After observing the natural process of the inundation of
silt and the find of
marine fossils in the
Taihang Mountains (hundreds of miles from the
Pacific Ocean), Shen Kuo devised a theory of land formation, or
geomorphology. He also adopted a theory of gradual
climate change in regions over time, after observing
petrified bamboo found underground at
Yan'an,
Shaanxi province. If not for Shen Kuo's writing, the architectural works of
Yu Hao would be little known, along with the inventor of
movable type printing,
Bi Sheng (990-
1051). Shen's contemporary
Su Song (1020–1101) was also a brilliant polymath, an astronomer who created a celestial atlas of star maps, wrote a pharmaceutical treatise with related subjects of
botany,
zoology,
mineralogy, and
metallurgy, and had erected a large
astronomical clocktower in
Kaifeng city in 1088. To operate the crowning
armillary sphere, his clocktower featured an
escapement mechanism and the world's oldest known use of an endless power-transmitting
chain drive.
The
Jesuit China missions of the 16th and 17th centuries "learned to appreciate the scientific achievements of this ancient culture and made them known in Europe. Through their correspondence European scientists first learned about the Chinese science and culture." Western academic thought on the history of Chinese technology and science was galvanized by the work of
Joseph Needham and the Needham Research Institute. Among the technological accomplishments of China were early
seismological detectors (
Zhang Heng in the 2nd century), the
water-powered celestial globe (Zhang Heng),
matches, the independent invention of the
decimal system,
dry docks, sliding
calipers, the double-action
piston pump,
cast iron, the
blast furnace, the
iron plough, the multi-tube
seed drill, the
wheelbarrow, the
suspension bridge, the
winnowing machine, the
rotary fan, the
parachute,
natural gas as fuel, the
raised-relief map, the
propeller, the
crossbow, and a solid fuel
rocket, the
multistage rocket, the
horse collar, along with contributions in
logic,
astronomy,
medicine, and other fields.
However, cultural factors prevented these Chinese achievements from developing into what could be called "science". According to Needham, it was the religious and philosophical framework of the Chinese intellectuals which made them unable to believe in the ideas of laws of nature:
Early experimental science
With the division of the Empire, the
Western Roman Empire lost contact with much of its past. The
Library of Alexandria, which had suffered since it fell under Roman rule, had been destroyed by 642, shortly after the
Arab conquest of Egypt. While the
Byzantine Empire still held learning centers such as
Constantinople, Western Europe's knowledge was concentrated in
monasteries until the development of
medieval universities in the
12th and
13th centuries. The curriculum of monastic schools included the study of the few available ancient texts and of new works on practical subjects like medicine and timekeeping.
Meanwhile, in the Middle East,
Greek philosophy was able to find some support under the newly created
Arab Empire. With the spread of
Islam in the 7th and 8th centuries, a period of
Muslim scholarship, known as the
Islamic Golden Age, lasted until the 14th century. This scholarship was aided by several factors. The use of a single language,
Arabic, allowed communication without need of a translator. Access to
Greek and
Latin texts from the
Byzantine Empire along with
Indian sources of learning provided Muslim scholars a knowledge base to build upon. In addition, there was the
Hajj, which facilitated scholarly collaboration by bringing together people and new ideas from all over the
Muslim world.
Science in the Islamic world
Muslim scientists placed far greater emphasis on
experiment than had the
Greeks. This led to an early
scientific method being developed in the Muslim world, where significant progress in methodology was made, beginning with the experiments of
Ibn al-Haytham (Alhazen) on
optics from
circa 1000, in his
Book of Optics. The most important development of the scientific method was the use of experiments to distinguish between competing scientific theories set within a generally
empirical orientation, which began among Muslim scientists. Ibn al-Haytham is also regarded as the father of optics, especially for his empirical proof of the intromission theory of light. Some have also described Ibn al-Haytham as the "first scientist" for his development of the modern scientific method.
Rosanna Gorini writes:
Due to the development of the modern scientific method,
Robert Briffault wrote in
The Making of Humanity:
In
mathematics, the
Persian mathematician
Muhammad ibn Musa al-Khwarizmi gave his name to the concept of the
algorithm, while the term
algebra is derived from
al-jabr, the beginning of the title of one of his publications. What is now known as
Arabic numerals originally came from India, but Muslim mathematicians did make several refinements to the number system, such as the introduction of
decimal point notation.
Sabian mathematician
Al-Battani (850-929) contributed to astronomy and mathematics, while
Persian scholar
Al-Razi contributed to chemistry.
In
astronomy,
Al-Battani improved the measurements of
Hipparchus, preserved in the translation of the Greek
Hè Megalè Syntaxis (
The great treatise) translated as
Almagest. Al-Battani also improved the precision of the measurement of the precession of the earth's axis. The corrections made to the
geocentric model by Al-Battani,
Averroes,
Nasir al-Din al-Tusi,
Mo'ayyeduddin Urdi and
Ibn al-Shatir were later incorporated into the
Copernican heliocentric model.
Heliocentric theories were also discussed by several other Muslim astronomers such as
Abu-Rayhan Biruni, Abu Said Sinjari,
Qutb al-Din al-Shirazi, and 'Umar al-Katibi al-
Qazwini.
Muslim
chemists and
alchemists played an important role in the foundation of modern
chemistry. Scholars such as
Will Durant and
Alexander von Humboldt regard Muslim chemists to be the founders of chemistry. In particular,
Geber is regarded as the "father of chemistry". The works of Arab chemists influenced
Roger Bacon (who introduced the empirical method to Europe, strongly influenced by his reading of Arabic writers), and later
Isaac Newton.
Many other advances were made by Muslim scientists in
biology (
botany,
evolution, and
zoology),
mathematics (
algebra,
arithmetic,
calculus,
geometry,
mathematical induction,
number theory, and
trigonometry),
alchemy and
chemistry, the
earth sciences (
anthropology,
cartography,
geodesy,
geography, and
geology),
physics (
optics,
mechanics, and
motion),
psychology (
experimental psychology,
psychiatry,
psychophysics, and
psychotherapy), and the
social sciences (
demography, history,
historiography, and
sociology).
Some of the most famous scientists from the Islamic world include
Geber (
polymath, father of
chemistry),
al-Farabi (polymath),
Abu al-Qasim (father of modern
surgery),
Ibn al-Haytham (
universal genius, father of
optics, founder of
psychophysics and
experimental psychology, pioneer of
scientific method, "first scientist"),
Abū Rayhān al-Bīrūnī (universal genius, father of
Indology and
geodesy, "first
anthropologist"),
Avicenna (universal genius, father of
momentum and modern
medicine),
Nasīr al-Dīn al-Tūsī (polymath), and
Ibn Khaldun (father of
demography,
cultural history,
historiography, the
philosophy of history,
sociology, and the
social sciences), among many others.
Science in Scholastic Europe
An intellectual revitalization of Europe started with the birth of
medieval universities in the 12th century. The contact with the Islamic world in
Spain and
Sicily, and during the
Reconquista and the
Crusades, allowed Europeans access to scientific
Greek and
Arabic texts, including the works of
Aristotle,
Ptolemy,
Geber,
al-Khwarizmi,
Alhazen,
Avicenna, and
Averroes. The European universities aided materially in the
translation and propagation of these texts and started a new infrastructure which was needed for scientific communities. As well as this, Europeans began to venture further and further east (most notably, perhaps,
Marco Polo) as a result of the
Pax Mongolica. This led to the increased influence of Indian and even Chinese science on the European tradition. Technological advances were also made, such as the early flight of
Eilmer of Malmesbury (who had studied Mathematics in 11th century
England), and the
metallurgical achievements of the
Cistercian blast furnace at
Laskill.
At the beginning of the 13th century there were reasonably accurate Latin translations of the main works of almost all the intellectually crucial ancient authors, allowing a sound transfer of scientific ideas via both the universities and the monasteries. By then, the natural philosophy contained in these texts began to be extended by notable
scholastics such as
Robert Grosseteste,
Roger Bacon,
Albertus Magnus and
Duns Scotus. Precursors of the modern scientific method, influenced by earlier contributions of the Islamic world, can be seen already in Grosseteste's emphasis on mathematics as a way to understand nature, and in the empirical approach admired by Bacon, particularly in his
Opus Majus. According to
Pierre Duhem, the
Condemnation of 1277 led to
the birth of modern science, because it forced thinkers to break from relying so much on
Aristotle, and to think about the world in new ways.
William of Ockham introduced the principle of
parsimony: natural philosophers shouldn't postulate unnecessary entities, so that motion isn't a distinct thing but is only the moving object and an intermediary "sensible species" isn't needed to transmit an image of an object to the eye. Scholars such as
Jean Buridan and
Nicole Oresme started to reinterpret elements of Aristotle's mechanics. In particular, Buridan developed the theory that impetus was the cause of the motion of projectiles, which was a first step towards the modern concept of
inertia. The
Oxford Calculators began to mathematically analyze the
kinematics of motion, making this analysis without considering the causes of motion.
In 1348, the
Black Death and other disasters sealed a sudden end to the previous period of massive philosophic and scientific development. Yet, the rediscovery of ancient texts was improved after the
Fall of Constantinople in 1453, when many
Byzantine scholars had to seek refuge in the West. Meanwhile, the introduction of printing (from China) was to have great effect on European society. The facilitated dissemination of the printed word democratized learning and allowed a faster propagation of new ideas. New ideas also helped to influence the development of European science at this point: not least the introduction of
Algebra. These developments paved the way for the
Scientific Revolution, which may also be understood as a resumption of the process of scientific change, halted at the start of the Black Death.
Early modern science
The renewal of learning in Europe, that began with 12th century
Scholasticism, came to an end about the time of the Black Death, and the initial period of the subsequent
Italian Renaissance is sometimes seen as a lull in scientific activity. The
Northern Renaissance, on the other hand, showed a decisive shift in focus from Aristoteleian natural philosophy to chemistry and the biological sciences (botany, anatomy, and medicine). Thus modern science in Europe was resumed in a period of great upheaval: the
Protestant Reformation and
Catholic Counter-Reformation; the discovery of the Americas by
Christopher Columbus; the
Fall of Constantinople; but also the re-discovery of Aristotle during the Scholastic period presaged large social and political changes. Thus, a suitable environment was created in which it became possible to question scientific doctrine, in much the same way that
Martin Luther and
John Calvin questioned religious doctrine. The works of
Ptolemy (astronomy),
Galen (medicine), and
Aristotle (physics) were found not always to match everyday observations. For example, an arrow flying through the air after leaving a bow contradicts Aristotle's laws of motion, which say that a moving object must be constantly under influence of an external force, as the natural state of earthly objects is to be at rest. Work by
Vesalius on human cadavers also found problems with the Galenic view of anatomy.
The willingness to question previously held truths and search for new answers resulted in a period of major scientific advancements, now known as the
Scientific Revolution. The Scientific Revolution is traditionally held by most historians to have begun in 1543, when
De Revolutionibus, by the astronomer
Nicolaus Copernicus, was first printed. The thesis of this book was that the Earth moved around the Sun. The period culminated with the publication of the
Philosophiae Naturalis Principia Mathematica in 1687 by
Isaac Newton.
Other significant scientific advances were made during this time by
Galileo Galilei,
Edmond Halley,
Robert Hooke,
Christiaan Huygens,
Tycho Brahe,
Johannes Kepler,
Gottfried Leibniz, and
Blaise Pascal. In philosophy, major contributions were made by
Francis Bacon, Sir
Thomas Browne,
René Descartes, and
Thomas Hobbes. The scientific method was also better developed as the modern way of thinking emphasized experimentation and reason over traditional considerations.
Modern science
The Scientific Revolution established science as the preeminent source for the growth of knowledge. The
early modern period is seen as a flowering of the Renaissance, in what is often known as the
Scientific Revolution, viewed as a foundation of modern science. During the 19th century, the practice of science became professionalized and institutionalized in ways which continued through the 20th century. As the role of scientific knowledge grew in society, it became incorporated with many aspects of the functioning of nation-states.
Natural sciences
Physics
The Scientific Revolution is a convenient boundary between ancient thought and classical physics.
Nicolaus Copernicus revived the
heliocentric model of the solar system described by
Aristarchus of Samos. This was followed by the first known model of planetary motion given by
Kepler in the early 17th century, which proposed that the planets follow
elliptical orbits, with the Sun at one focus of the ellipse.
Galileo also made use of experiments to validate physical theories, a key element of the scientific method.
In 1687,
Isaac Newton published the
Principia Mathematica, detailing two comprehensive and successful physical theories:
Newton's laws of motion, which lead to classical mechanics; and
Newton's Law of Gravitation, which describes the fundamental force of gravity. The behavior of electricity and magnetism was studied by
Faraday,
Ohm, and others during the early 19th century. These studies led to the unification of the two phenomena into a single theory of
electromagnetism, by
Maxwell (known as
Maxwell's equations).
The beginning of the 20th century brought the start of a revolution in physics. The long-held theories of Newton were shown not to be correct in all circumstances. Beginning in 1900,
Max Planck,
Albert Einstein,
Niels Bohr and others developed quantum theories to explain various anomalous experimental results, by introducing discrete energy levels. Not only did quantum mechanics show that the laws of motion didn't hold on small scales, but even more disturbingly, the theory of
general relativity, proposed by Einstein in 1915, showed that the fixed background of
spacetime, on which both
Newtonian mechanics and
special relativity depended, couldn't exist. In 1925,
Werner Heisenberg and
Erwin Schrödinger formulated
quantum mechanics, which explained the preceding quantum theories. The observation by
Edwin Hubble in 1929 that the speed at which galaxies recede positively correlates with their distance, led to the understanding that the universe is expanding, and the formulation of the
Big Bang theory by
Georges Lemaître.
Further developments took place during World War II, which led to the practical application of
radar and the development and use of the
atomic bomb. Though the process had begun with the invention of the
cyclotron by
Ernest O. Lawrence in the 1930s, physics in the postwar period entered into a phase of what historians have called "
Big Science", requiring massive machines, budgets, and laboratories in order to test their theories and move into new frontiers. The primary patron of physics became state governments, who recognized that the support of "basic" research could often lead to technologies useful to both military and industrial applications. Currently, general relativity and quantum mechanics are inconsistent with each other, and efforts are underway to unify the two.
Chemistry
The history of modern chemistry can be taken to begin with the distinction of chemistry from
alchemy by
Robert Boyle in his work
The Sceptical Chymist, in 1661 (although the alchemical tradition continued for some time after this) and the gravimetric experimental practices of medical chemists like
William Cullen,
Joseph Black,
Torbern Bergman and
Pierre Macquer. Another important step was made by
Antoine Lavoisier(father of modern chemistry) through his recognition of
oxygen and the law of
conservation of mass, which refuted
phlogiston theory. Proof that all matter is made of atoms, which are the smallest constituents of matter that can't be broken down without losing the basic chemical and physical properties of that matter, was provided by
John Dalton in 1803. He also formulated the law of mass relationships. In 1869,
Dmitri Mendeleev composed his
periodic table of elements on the basis of Dalton's discoveries.
The synthesis of
urea by
Friedrich Wöhler opened a new research field,
organic chemistry, and by the end of the 19th century, scientists were able to synthesize hundreds of organic compounds. The later part of the nineteenth century saw the exploitation of the Earth's petrochemicals, after the exhaustion of the oil supply from
whaling. By the twentieth century, systematic production of refined materials provided a ready supply of products which provided not only energy, but also synthetic materials for clothing, medicine, and everyday disposable resources. Application of the techniques of organic chemistry to living organisms resulted in
physiological chemistry, the precursor to
biochemistry. The twentieth century also saw the integration of physics and chemistry, with chemical properties explained as the result of the electronic structure of the atom.
Linus Pauling's book on
The Nature of the Chemical Bond used the principles of quantum mechanics to deduce
bond angles in ever-more complicated molecules. Pauling's work culminated in the physical modelling of
DNA,
the secret of life (in the words of
Francis Crick, 1953). In the same year, the
Miller-Urey experiment demonstrated in a simulation of primordial processes, that basic constituents of proteins, simple
amino acids, could themselves be built up from simpler molecules.
Geology
Geology existed as a cloud of isolated, disconnected ideas about rocks, minerals, and landforms long before it became a coherent science.
Theophrastus' work on rocks
Peri lithōn remained authoritative for millennia: its interpretation of fossils wasn't overturned until after the Scientific Revolution. Chinese polymath
Shen Kua (1031 - 1095) was the first to formulate hypotheses for the process of land formation. Based on his observation of fossils in a geological
stratum in a mountain hundreds of miles from the ocean, he deduced that the land was formed by erosion of the mountains and by
deposition of silt.
Geology wasn't systematically restructured during the
Scientific Revolution, but individual theorists made important contributions.
Robert Hooke, for example, formulated theory of earthquakes, and
Nicholas Steno developed the theory of
superposition and argued that
fossils were the remains of once-living creatures. Beginning with
Thomas Burnet's
Sacred Theory of the Earth in 1685, natural philosophers began to explore the idea that the Earth had changed over time. Burnet and his contemporaries interpreted Earth's past in terms of events described in the Bible, but their work laid the intellectual foundations for secular interpretations of Earth history.
Modern geology, like modern chemistry, gradually evolved during the 1700s and early 1800s.
Benoit de Maillet and the
Comte de Buffon argued that Earth was much older than the 6,000 years envisioned by biblical scholars.
Jean-Etienne Guettard and
Nicolas Desmarest hiked central France and recorded their observations on some of the first geological maps.
Abraham Werner created a systematic classification scheme for rocks and minerals--an achievement as significant for geology as that of
Linnaeus was for biology. Werner also proposed a generalized interpretation of Earth history, as did contemporary Scottish polymath
James Hutton.
Georges Cuvier and
Alexandre Brongniart, expanding on the work of
Steno, argued that layers of rock could be dated by the fossils they contained: a principle first applied to the geology of the Paris Basin. The use of
index fossils became a powerful tool for making geological maps, because it allowed geologists to correlate the rocks in one locality with those of similar age in other, distant localities. Over the first half of the nineteenth century, geologists such as
Charles Lyell,
Adam Sedgwick, and
Roderick Murchison applied the new technique to rocks throughout Europe and eastern North America, setting the stage for more detailed, government-funded mapping projects in later decades.
Midway through the 19th century, the focus of geology shifted from description and classification to attempts to understand
how the surface of the Earth changed. The first comprehensive theories of mountain building were proposed during this period, as were the first modern theories of earthquakes and volcanoes.
Louis Agassiz and others established the reality of continent-covering
ice ages, and "fluvialists" like
Andrew Crombie Ramsay argued that river valleys were formed, over millions of years by the rivers that flow through them. After the discovery of
radioactivity,
radiometric dating methods were developed, starting in the 1900s.
Alfred Wegener's theory of "continental drift" was widely dismissed when it was proposed in the 1910s, but new data gathered in the 1950s and 1960s led to the theory of
plate tectonics, which provided a plausible mechanism for it.
Plate tectonics also provided a unified explanation for a wide range of seemingly unrelated geological phenomena. Since 1970 it has been the unifying principle in geology.
Geologists' embrace of
plate tectonics was part of a broadening of the field from a study of rocks into a study of the Earth as a planet. Other elements of this transformation include: geophysical studies of the interior of the Earth, the grouping of geology with
meteorology and
oceanography as one of the "earth sciences", and comparisons of Earth and the solar system's other rocky planets.
Astronomy
Advances in astronomy and in optical systems in the 19th century resulted in the first observation of an
asteroid (
1 Ceres) in 1801, and the discovery of
Neptune in 1846.
George Gamow,
Ralph Alpher, and
Robert Hermann had calculated that there should be evidence for a Big Bang in the background temperature of the universe. In 1964,
Arno Penzias and
Robert Wilson discovered a 3 kelvin background hiss in their
Bell Labs radiotelescope, which was evidence for this hypothesis, and formed the basis for a number of results that helped determine the
age of the universe.
Supernova
SN1987A was observed by astronomers on Earth both visually, and in a triumph for
neutrino astronomy, by the solar neutrino detectors at
Kamiokande. But the solar neutrino flux was
a fraction of its theoretically-expected value. This discrepancy forced a change in some values in the
standard model for
particle physics.
Biology, medicine, and genetics
In 1847, Hungarian physician
Ignác Fülöp Semmelweis dramatically reduced the occurrency of
puerperal fever by the simple experiment of requiring physicians to wash their hands before attending to women in childbirth. This discovery predated the
germ theory of disease. However, Semmelweis' findings were not appreciated by his contemporaries and came into use only with discoveries by British surgeon
Joseph Lister, who in 1865 proved the principles of
antisepsis. Lister's work was based on the important findings by French biologist
Louis Pasteur. Pasteur was able to link microorganisms with disease, revolutionizing medicine. He also devised one of the most important methods in
preventive medicine, when in 1880 he produced a
vaccine against
rabies. Pasteur invented the process of
pasteurization, to help prevent the spread of disease through milk and other foods.
Perhaps the most prominent and far-reaching theory in all of science has been the theory of
evolution by
natural selection put forward by the British naturalist
Charles Darwin in his
On the Origin of Species in 1859. Darwin's theory proposed that all differences in animals were formed by natural processes over long periods of time, and that even humans were simply evolved organisms. Implications of evolution on fields outside of pure science have led to both
opposition and support from different parts of society, and profoundly influenced the popular understanding of "man's place in the universe". In the early 20th century, the study of heredity became a major investigation after the rediscovery in 1900 of the laws of inheritance developed by the
Moravian monk
Gregor Mendel in 1866. Mendel's laws provided the beginnings of the study of
genetics, which became a major field of research for both scientific and industrial research. By 1953,
James D. Watson,
Francis Crick and
Rosalind Franklin clarified the basic structure of DNA, the
genetic material for expressing life in all its forms. In the late 20th century, the possibilities of
genetic engineering became practical for the first time, and a massive international effort began in 1990 to map out an entire human
genome (the
Human Genome Project) has been touted as potentially having large medical benefits.
Ecology
The discipline of
ecology typically traces its origin to the synthesis of
Darwinian evolution and
Humboldtian biogeography, in the late 19th and early 20th centuries. Equally important in the rise of ecology, however, were
microbiology and
soil science—particularly the
cycle of life concept, prominent in the work
Louis Pasteur and
Ferdinand Cohn. The word
ecology was coined by
Ernst Haeckel, whose particularly holistic view of nature in general (and Darwin's theory in particular) was important in the spread of ecological thinking. In the 1930s,
Arthur Tansley and others began developing the field of
ecosystem ecology, which combined experimental soil science with physiological concepts of energy and the techniques of
field biology. The history of ecology in the 20th century is closely tied to that of
environmentalism; the
Gaia hypothesis in the 1960s and more recently the scientific-religious movement of
Deep Ecology have brought the two closer together.
Social sciences
Successful use of the scientific method in the physical sciences led to the same methodology being adapted to better understand the many fields of human endeavor. From this effort the social sciences have been developed.
Political science
While the study of politics is first found in
Western culture in
Ancient Greece, political science is a late arrival in terms of
social sciences. However, the discipline has a clear set of antecedents such as
moral philosophy,
political philosophy,
political economy, history, and other fields concerned with
normative determinations of what ought to be and with
deducing the characteristics and functions of the ideal
state. In each historic period and in almost every geographic area, we can find someone studying politics and increasing political understanding.
The antecedents of politics trace their roots back even earlier than
Plato and
Aristotle, particularly in the works of
Homer,
Hesiod,
Thucydides,
Xenophon, and
Euripides. Later, Plato analyzed political systems, abstracted their analysis from more
literary- and history- oriented studies and applied an approach we'd understand as closer to
philosophy. Similarly, Aristotle built upon Plato's analysis to include historical empirical evidence in his analysis.
During the rule of
Rome, famous historians such as
Polybius,
Livy and
Plutarch documented the rise of the Roman
Republic, and the organization and histories of other nations, while
statesmen like
Julius Caesar,
Cicero and others provided us with examples of the politics of the republic and Rome's empire and wars. The study of politics during this age was oriented toward understanding history, understanding methods of governing, and describing the operation of governments.
With the
fall of the Roman Empire, there arose a more diffuse arena for political studies. The rise of
monotheism and, particularly for the Western tradition,
Christianity, brought to light a new space for politics and political action. During the
Middle Ages, the study of politics was widespread in the churches and courts. Works such as
Augustine of Hippo's
The City of God synthesized current philosophies and political traditions with those of
Christianity, redefining the borders between what was religious and what was political. Most of the political questions surrounding the relationship between
church and state were clarified and contested in this period.
In the
Middle East and later other
Islamic areas, works such as the
Rubaiyat of Omar Khayyam and Epic of Kings by
Ferdowsi provided evidence of political analysis, while the
Islamic aristotelians such as
Avicenna and later
Maimonides and
Averroes, continued
Aristotle's tradition of analysis and
empiricism, writing commentaries on Aristotle's works.
During the
Italian Renaissance,
Niccolò Machiavelli established the emphasis of modern political science on direct
empirical observation of political
institutions and actors. Later, the expansion of the scientific paradigm during the
Enlightenment further pushed the study of politics beyond normative determinations. In particular, the study of
statistics, to study the subjects of the
state, has been applied to
polling and
voting.
In the 20th century, the study of ideology, behaviouralism and international relations led to a multitude of 'pol-sci' subdisciplines including
voting theory,
game theory (also used in economics),
psephology,
political geography/
geopolitics,
political psychology/
political sociology,
political economy,
policy analysis,
public administration, comparative political analysis and
peace studies/conflict analysis.
Linguistics
Historical linguistics emerged as an independent field of study at the end of the 18th century.
Sir William Jones proposed that
Sanskrit,
Persian,
Greek,
Latin,
Gothic, and
Celtic languages all shared a common base. After Jones, an effort to catalog all languages of the world was made throughout the 19th century and into the 20th century. Publication of
Ferdinand de Saussure's
Cours de linguistique générale spawned the development of
descriptive linguistics. Descriptive linguistics, and the related
structuralism movement caused linguistics to focus on how language changes over time, instead of just describing the differences between languages.
Noam Chomsky further diversified linguistics with the development of
generative linguistics in the 1950s. His effort is based upon a mathematical model of language that allows for the description and prediction of valid
semantics. Additional specialties such as
sociolinguistics,
cognitive linguistics, and
computational linguistics have emerged from collaboration between linguistics and other disciplines.
Economics
The basis for
classical economics forms
Adam Smith's
An Inquiry into the Nature and Causes of the Wealth of Nations, published in 1776. Smith criticized
mercantilism, advocating a system of free trade with
division of labour. He postulated an "
Invisible Hand" that large economic systems could be self-regulating through a process of enlightened self-interest.
Karl Marx developed an alternative economical system, called
Marxian economics. Marxian economics is based on the
labor theory of value and assumes the value of good to be based on the amount of labor required to produce it. Under this assumption,
capitalism was based on employeers not paying the full value of workers labor to create profit. The
Austrian school responded to Marxian economics by viewing
entrepreneurship as driving force of economic development. This replaced the labor theory of value by a system of
supply and demand.
In the 1920s,
John Maynard Keynes prompted a division between
microeconomics and
macroeconomics. Under
Keynesian economics macroeconomic trends can overwhelm economic choices made by individuals. Governments should promote
aggregate demand for goods as a means to encourage economic expansion. Following World War II,
Milton Friedman created the concept of
monetarism. Monetarism focuses on using the supply and demand of money as a method for controlling economic activity. In the 1970s, monetarism has adapted into
supply-side economics which advocates reducing taxes as a means to increase the amount of money available for economic expansion.
Other modern schools of economic thought are
New Classical economics and
New Keynesian economics. New Classical economics was developed in the 1970s, emphasizing solid microeconomics as the basis for macroeconomic growth. New Keynesian economics was created partially in response to New Classical economics, and deals with how inefficiencies in the market create a need for control by a central bank or government.
Psychology
The end of the 19th century marks the start of psychology as a scientific enterprise. The year 1879 is commonly seen as the start of psychology as an independent field of study. In that year
Wilhelm Wundt founded the first laboratory dedicated exclusively to psychological research (in
Leipzig). Other important early contributors to the field include
Hermann Ebbinghaus (a pioneer in memory studies),
Ivan Pavlov (who discovered
classical conditioning), and
Sigmund Freud. Freud's influence has been enormous, though more as cultural icon than a force in scientific psychology.
The 20th century saw a rejection of Freud's theories as being too unscientific, and a reaction against
Edward Titchener's atomistic approach of the mind. This led to the formulation of
behaviorism by
John B. Watson, which was popularized by
B.F. Skinner. Behaviorism proposed
epistemologically limiting psychological study to overt behavior, since that could be reliably measured. Scientific knowledge of the "mind" was considered too metaphysical, hence impossible to achieve.
The final decades of the 20th century have seen the rise of a new interdisciplinary approach to studying human psychology, known collectively as
cognitive science. Cognitive science again considers the mind as a subject for investigation, using the tools of
evolutionary psychology,
linguistics,
computer science,
philosophy, and
neurobiology. New methods of visualizing the activity of the brain, such as
PET scans and
CAT scans, began to exert its influence as well. These new forms of investigation assume that a wide understanding of the human mind is possible, and that such an understanding may be applied to other research domains, such as
artificial intelligence.
Sociology
Ibn Khaldun is regarded as the founder of modern sociology. As a scientific discipline, sociology emerged in the early 19th century as the academic response to the modernization of the world. Among many early sociologists (for example,
Émile Durkheim), the aim of sociology was in
structuralism, understanding the cohesion of social groups, and developing an "antidote" to social disintegration.
Max Weber was concerned with the modernization of society through the concept of
rationalization, which he believed would trap individuals in an "iron cage" of rational thought. Some sociologists, including
Georg Simmel and
W. E. B. Du Bois, utilized more
microsociological, qualitative analyses. This microlevel approach played an important role in American sociology, with the theories of
George Herbert Mead and his student
Herbert Blumer resulting in the creation of the
symbolic interactionism approach to sociology.
American sociology in the 1940s and 1950s was dominated largely by
Talcott Parsons, who argued that aspects of society that promoted structural integration were therefore "functional". This
structural functionalism approach was questioned in the 1960s, when sociologists came to see this approach as merely a justification for inequalities present in the status quo. In reaction,
conflict theory was developed, which was based in part on the philosophies of
Karl Marx. Conflict theorists saw society as an arena in which different groups compete for control over resources. Symbolic interactionism also came to be regarded as central to sociological thinking.
Erving Goffman saw social interactions as a stage performance, with individuals preparing "backstage" and attempting to control their audience through
impression management. While these theories are currently prominent in sociological thought, other approaches exist, including
feminist theory,
post-structuralism,
rational choice theory, and
postmodernism.
Anthropology
Anthropology can best be understood as an outgrowth of the
Age of Enlightenment. It was during this period that Europeans attempted systematically to study human behaviour. Traditions of jurisprudence, history, philology and sociology developed during this time and informed the development of the social sciences of which anthropology was a part.
At the same time, the romantic reaction to the Enlightenment produced thinkers such as
Johann Gottfried Herder and later
Wilhelm Dilthey whose work formed the basis for the
culture concept which is central to the discipline. Traditionally, much of the history of the subject was based on
colonial encounters between Europe and the rest of the world, and much of 18th- and 19th-century anthropology is now classed as forms of
scientific racism.
During the late 19th-century, battles over the "study of man" took place between those of an "anthropological" persuasion (relying on
anthropometrical techniques) and those of an "
ethnological" persuasion (looking at cultures and traditions), and these distinctions became part of the later divide between
physical anthropology and
cultural anthropology, the latter ushered in by the students of
Franz Boas.
In the mid-20th century, much of the methodologies of earlier anthropological and ethnographical study were reevaluated with an eye towards research ethics, while at the same time the scope of investigation has broadened far beyond the traditional study of "primitive cultures" (scientific practice itself is often an arena of anthropological study).
The emergence of
paleoanthropology, a scientific discipline which draws on the
methodologies of
paleontology,
physical anthropology and
ethology, among other disciplines, and increasing in scope and momentum from the mid-20th century, continues to yield further insights into human origins, evolution, genetic and cultural heritage, and perspectives on the contemporary human predicament as well.
Emerging disciplines
During the 20th century, a number of interdisciplinary scientific fields have emerged. Three examples will be given here:
Communication studies combines
animal communication,
information theory,
marketing,
public relations,
telecommunications and other forms of communication.
Computer science, built upon a foundation of
theoretical linguistics,
discrete mathematics, and
electrical engineering, studies the nature a
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