History of science
Modern science is a body of verifiable empirical knowledge, a global community of scholars, and a set of techniques for investigating the universe known as the scientific method. The history of science traces these phenomena and their pre-cursors back in time, all the way into human prehistory.
The Scientific Revolution saw the inception of the modern scientific method to guide the evaluation of knowledge. This change is considered to be so fundamental that older inquiries are known as pre-scientific. Still, many place ancient natural philosophy clearly within the scope of the history of science.
The history of mathematics, the history of technology, and the history of philosophy are covered in different articles. Mathematics is closely related to, but distinct from science (at least in the modern conception). Technology concerns the creative process of designing useful objects and systems, which differs from the search for empirical truth. Philosophy differs from science in that, while both the natural and the social sciences attempt to base their theories on established fact, philosophy also enquires about other areas of knowledge, notably ethics. In practice, each of these fields is heavily used by the others - but only as an external tool.
Patterns in the history of science
An influential account of the history of science is The Structure of Scientific Revolutions (1962) by Thomas Kuhn (1922-1996). Kuhn warned against the view of scientific progress as a linear accumulation of facts, each one simply adding to the last. He argued out that different phases of scientific development exist in different paradigms, which are incommensurate - that is, they make fundamentally different assumptions about the universe. An example is the difference between the physics of Aristotle (384 BC - 322 BC), Isaac Newton (1642-1727) (classical mechanics), Albert Einstein (1879-1955) (Relativity), and quantum mechanics (established in 1925). Kuhn claimed that far from merely building on the previous theory's accomplishments, each one essentially throws out the old way of looking at the universe, and comes up with its own vocabulary to describe it and its own guidelines for expanding knowledge within the new paradigm.
Pre-experimental "science"
From Antiquity up to the time of the Scientific Revolution, inquiry into the workings of the universe was known as natural philosophy, but this included fields of study which today have been divorced from science. The ancient people of Western civilization who we might think of as scientists may have thought of themselves as natural philosophers. In other cases, systematic learning about the natural world was a direct outgrowth of religion, often as a project of a particular religious community. An account of the development of (natural) philosophy from ancient times until recent times can be found in Bertrand Russell's History of Philosophy.
One important feature of non-scientific natural philosophy is a reluctance to engage in experiment. For example, Aristotle is one of the most prolific natural philosophers of antiquity. He made countless observations of nature, especially the habits and attributes of plants and animals in the world around him, which he devote considerable attention to categorizing. He also made many observations about the large-scale workings of the universe, which led to his development of a comprehensive theory of physics in his missives of the same name. (See Physics (Aristotle).)
But Aristotle did not make predictions in the way that modern scientific theories are expected to. His approach was to observe nature, to use deductive reasoning and inductive reasoning to explain everything, and to use his natural observations to illustrate his explanations. For example, he developed a version of the classical theory of the elements (earth, water, fire, air, and aether). In his theory, the heavier elements (earth, water) had a natural tendency to move toward the center of the universe (what we would now call the center of the Earth), and the lighter elements a natural tendency to move away from it. (Aether was what celestial bodies - e.g. planets and stars - were supposedly made of.)
Aristotle could point to the falling stone, rising flames, or pouring water to illustrate his theory. His laws of movement hypothesized that friction was an omni-present phenomenon - that any body in motion would, unless acted upon, come to rest. He also proposed that heavier objects fall faster, and that voids were impossible.
But until the time of the Scientific Revolution, these theories were never really tested experimentally. At the time, the utility of experiment was unproven. Some believed that setting up artificial conditions in an experiment could never produce results that described nature as it was in the world around them.
When investigated experimentally by burning objects in closed spaces, it was eventually determined that air was not elemental. This led to the development of phlogiston theory and later to discovery of the role of oxygen in combustion.
Galileo (1638) investigated the motion of falling bodies, and found that heavier bodies, in fact, do not always fall faster. The experimental results of Copernicus, Kepler and Galileo were formalized in Newton's laws of motion. Newton would state that inertia is an inherent property of mass: a moving body will stay in motion unless acted upon. Unlike Aristotle's views, Newton would state that friction is not an inherent property of objects; friction seems omni-present because we live in an environment filled with fluids like air and water, which maintain continual contact with all objects immersed in them.
Other revolutionary investigations of the period produced the vacuum, a void of the sort that Aristotle thought impossible. Today, one of the results of quantum mechanics is the notion that even vacuum possesses properties (see quantum foam) which were unsuspected during the time of the Scientific Revolution.
Aristotle's predecessor, Plato (c. 427 BC – c. 347 BC), was similarly non-experimental. Plato studied the phenomenon of refraction. Due to changes in velocity, light changes its path when it passes from one material to another with a different index of refraction, such as from air to water or from water to glass. He formulated a law to describe the relationship between the angle of incidence and the angle of refraction (what we might think of now as the incoming and outgoing light beams). He even formulated a procedure by which one might measure these angles in various situations, involving a basin of water or a piece of glass. In his treatise, he helpfully supplies a table which shows how the observed angles match exactly what his law predicts. It is likely, however, that Plato never actually performed his thought experiment, because he would not have gotten the results he reports (which are an exact match, down to the last decimal place, to his theory). Plato's theory of refraction is actually quite incorrect, and differs by an easily detectable amount from the modern theory of refraction. He essentially used his "experiment" as an illustration of his theory, not as a test of its validity. His assertions, like those of Aristotle, went untested by his peers and remained unchallenged for centuries. It was the Egyptian scientist Ibn al Haythen (known in Western Europe as Alhazen) (965-1040), who finally discounted it with a mixture of logic and experimentation. His studies of light, published in the book "Optics" in 1015 to 1021, during the era of the Moorish Empire, are possibly the earliest work to use the scientific method and were very influential in later studies of light. It was translated into Latin around 1270, which brought this knowledge to Western Europe. Other Arab scholars influenced the development of science in similar manner, be it through their own work or through the works of Antiquity that the Arab world preserved.
Science as a social enterprise
Main article: Science studies
Science is developing exponentially. In antiquity the natural philosophers had relatively few peers. The few people who were able to engage in natural inquiry were either wealthy themselves, had rich benefactors, or had the support of a religious community. In contrast, today there are more scientists alive now than have lived in all previous times. Scientific research has tremendous government support and also ongoing support from the private sector. Available methods of communication have improved tremendously over time. Instead of waiting months or years for a hand-copied letter to arrive, today scientific communication is instant. Earlier, most natural philosophers worked in relative isolation, due to the difficulty and slowness of communication. Still, there was a considerable amount of cross-fertilization between distant groups and individuals.
Nowadays, almost all modern scientists participate in a scientific community, usually global in nature, but also strongly segregated into different fields of study. The scientific community is important because it represents a source of established knowledge which, if used properly, will be more reliable than personally acquired knowledge of any given individual. The community also provides a feedback mechanism. The proper scientific feedback mechanisms are peer review and for reproducibility. Most scientific content (experimental results, theoretical proposals, or literature reviews) is reported in a scientific journal. The most reputable journals have a highly elaborate process of peer review. After publication in any journal, others have the opportunity to comment on it in order to hash out the objective truths of the phenomenon in question. Another fundamental activity is the attempt to replicate experimental results, either using the same techniques at the hands of a different group of people at a different institution, or by using different techniques to determine the same facts. Experimental results that cannot be replicated are always suspect, although some complex experiments can often be difficult to reproduce correctly.
A major development of the Scientific Revolution was the foundation of scientific societies: Academia Secretorum Naturae (Accademia dei Segreti, the Academy of the Mysteries of Nature) can be considered the first scientific community; founded in Naples 1560 by Giambattista della Porta, the society was soon shut down by Pope Paul V under suspicion of sorcery. It was replaced by the Accademia dei Lincei, founded in Rome 1603, included Galileo as a member, but failed upon his condemnation in 1633. The Accademia del Cimento, Florence 1657, lasted 10 years. The Royal Society of London, 1660 to the present day, brought together a diverse collection of scientists to discuss theories, conduct experiments, and review each other's work. The Académie des Sciences was created as an institution of the government of France 1666, meeting in the King's library. The Akademie der Wissenschaften began in Berlin 1700. This practice is now an established part of modern science. Scientists frequently come together in scientific conferences to present and discuss their research results. Today it is the rare nation that does not have its National Academy of Sciences or its Max Planck Institute.
Major events in the history of scientific communication
- The cave paintings depicted events, with no commentary.
- The Ishango Bone dated 25,000 years ago could only show tallies in mathematical notation.
- The clay tablets of Mesopotamia show the scale of the commentary or the information: the argument and logic of a discovery would be limited to what fit on the tablet.
- The parchment and paper scrolls which arose in Greek and in Chinese culture could start to contain the history and development of ideas and discoveries.
- The codex or book of medieval times allowed random access to specific passages. The systematic printing and production of books could then allow the systematic production of new ideas.
- By the twentieth century, the scale and scope of scientific work allowed collaboration of researchers and the definition of consistent protocols for this collaboration in scientific work.
History
Prehistoric times
Although, by definition, no writing records were made in prehistoric time, we can get some insight as to how the world, and its mechanisms, was understood or interpreted by prehistoric man by direct and indirect evidence. Direct evidence includes cave paintings that were found in Spain and France, and some other artistic works, for example the Venus of Willendorf. Other direct evidence are bones (for example trepanation) and ancient tools[1]. Despite the relative lack of direct evidence of knowledge owned by prehistoric man, the surviving technologies of prehistory may also be used to conject as to the understanding of the world in that era.
Survival was the first order of business; even today, with the great tsunami of 2004, Andaman Islanders remembered the advice of their forebears, took to the high ground, and survived the tsunami, as their ancestors have since time immemorial. These peoples recounted this knowledge to the crews of the rescue aircraft who were hovering over the Andaman Islands, after the aircraft were attacked by their arrows.
In the past, after the problem of survival was solved for groups of people, human beings could then devote their attention to their world, including the sky, the Sun, the Moon, and the stars. The inherent regularities of the behavior of these astronomical bodies allowed human beings to collect and record the apparent positions of these bodies in the sky.
Thus human beings have sought knowledge in the past, and today still seek scientific laws which they can depend on. But in prehistoric times, advice and knowledge was passed from generation to generation in an oral tradition. Note that prehistory ends at different times for different cultures. Thus the Andaman Islanders might still be in prehistory, and the Papuans left their prehistory about 1900 (for which archaeologists, anthropologists and linguists can be grateful, as they have still laboratories in which to study their theories).
Ancient civilizations
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.
Mesopotamia
From their beginnings in Sumer (now Iraq) around 3500 BC the Mesopotamian peoples began to attempt to record the world in extremely thorough quantitative and numerical data to whatever extent control allowed, seemingly without the desire or ability to reduce such information to scientific laws (of which none exist). An example of this practice is notable in their use of an unformulated version of Pythagoras' law as early as the 18th century BC.[2]
A science which lent itself to this form of recording and study was astronomy. In fact, even today the astronomical cycles identified by Mesopotamian scientists are still widely used in Western calendars: the solar year, the lunar month, the seven-day week. The vigorous noting of the motions of the stars, planets, and the moon are left on thousands of clay tablets created by scribes. With collected data the motion of celestial bodies was able to be predicted in the short term. Astronomy and Astrology were considered to be the same thing, a fact proven by the practice of this science in Babylonia by priests. Indeed, rather than following the modern trend towards rational science, moving away from superstition and belief; the Mesopotamian astronogy conversely became more astrology-based later in the civilisation - studying the stars in terms of horoscopes and omens.
Kidinnu was a Chaldean astronomer and mathematician who was contemporary with the Greek astronomers.
Indic
The observatories of India and Persia were buildings to facilitate observation with the naked eye, much like the stone circles of Europe. Eventually they were miniaturized into the diptychs and astrolabes in use by the Greeks. They facilitated development of early astronomy. Astronomical references of chronological significance (e.g., the beginning of the year; the vernal equinox in Orion around 4500 BC) can be found in the Vedas. Fire altars, with astronomical basis, have been found in third millennium cities of India. Their design can be conservatively dated to the 1st millennium BC. Around 1800 BC, Yajnavalkya already advanced a 95-year cycle to synchronize the motions of the sun and the moon. In a treatise from the 6th century, a summary of five astronomical systems can be found.
Ancient Indian culture has always been diverse in its choice of spices, condiments and ornamental items, hence India was the origin of palm and coconut oil, indigo and other vegetable dyes and pigments like cinnabar. Many of the dyes were used in art and sculpture. The use of perfumes demonstrates some knowledge of the application of chemistry, particularly in distillation and purification processes.
In medicine, inoculation was practiced in China, India, and Turkey. Inoculation was a precursor to vaccination for smallpox.
Egyptian
Significant advances in Ancient Egypt include astronomy, mathematics and medicine. Their invention of 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 western world.
The Egyptian hieroglyphs, a phonetic writing system, has served as the basis for the Phoenician alphabet from which the later Hebrew, Greek, Latin, Arabic, and Cyrillic alphabets were derived. The city of Alexandria retained preeminence with its library, which was so great that it became a symbol for knowledge itself. Much of it was destroyed in fire in the first centuries AD. A huge amount of antique literature and knowledge was lost.
Græco-Roman
The systematic search for natural laws can be said to start with Hellenic civilization, which reached its zenith in the 4th century BC, and served as the intellectual background for western civilization up to the time of the Scientific Revolution. The philosophies of Socrates, Plato, and Aristotle being preeminent during this period, while Hippocrates laid the foundations of medicine as a branch of science.
The military campaigns of Alexander the Great spread Greek thought through Egypt, Asia Minor, Persia, and to the Indus River. The resulting Hellenistic civilization produced seat of learning in Alexandria and Antioch along with Greek speaking populations across several monarchies.
Hellenistic geometers such as Archimedes, Apollonius of Perga, and Euclid built upon the work of the Hellenic era Pythagoreans. Eratosthenes used his knowledge of geometry to measure the distance between the Sun and the Earth along with the size of the Earth.
Astronomers like Hipparchus built upon the measurements of the Chaldean astronomers before him, to measure the precession of the Earth. Hipparchus in 129 BC recorded the first star map when he observed a nova, and wished to preserve astronomical record of the stars, so that other novas could be discovered. A copy of his star map was found sitting atop the broad shoulders of a seven-foot statue known as the Farnese Atlas.[3] Ptolemy established many of the constellations used today though the Almagest. The Ptolemaic system also became the dominant model for the motions of the heavens.
Roman era contributions include expanding knowledge of anatomy and physiology by the physician Galen. His primary contribution was to have carefully dissected and observed dogs, pigs, and barbary apes, using the results to describe such structures as the nervous system, heart, and kidneys. He demonstrated that arteries carry blood instead of air and added greatly to knowledge of the brain, nerves, spinal cord, and pulse. [4]
The Roman theologian Augustine of Hippo, in his book Confessions, expanded upon Aristotle's philosophies in the areas of thought, memory, and time.
Tribal Europe
By 1000 BC - 500 BC the Germanic tribes had a bronze age civilization, while the Celts were in the iron age by the time of the Hallstatt culture. Their cultures next collided with the military and agricultural practices of the Romans, two millennia ago. But the time and resources which are needed to conduct science had to build up gradually.
Persia
Scientific studies, especially in medicine and chemistry, were conducted by Sassanid physicians. The Academy of Gundishapur was an early teaching hospital established during this time.
China
Joseph Needham's Science and Civilisation in China lists a number of early discoveries, among which important ones in astronomy and medicine. In astronomy, The book Gan Shi Xing Jing (甘石星经) of the Warring States Period (403 BC to 221 BC) is the earliest star catalogue in the world. An important occasion was July 4, 1054, when Chinese astronomers noted the appearance of a guest star, the supernova now called the Crab Nebula, Messier's M1. In mathematics, Zu Chongzhi (祖冲之) of the Northern and Southern Dynasties was the first person to calculate the value of Pi to seven decimal places.
Korea
Korean science and Korean technology are little known in the west but involve significant discoveries, particularly in medicine, and invaluable astronomical records of meteor showers, and eclipses particularly from 1500-1750 in the Annals of the Joseon Dynasty.
Maya
The Maya calendar utilized a base-20 number system which included the 'number' zero (also see Maya numerals). The astronomy was advanced enough to support an accurate calendar.
Inca
The engineering skills of the Inca were great, even by today's standards. An example is the use of pieces weighing in upwards of one ton in their stonework (e.g., Machu Picchu in Peru), placed together so that not even a blade can fit in-between the cracks. The villages used irrigation canals and drainage systems, making agriculture very efficient.
Rest of the world
Although there is no written record of scientific discovery for some peoples or cultures, there is some evidence for their achievements in exploration: for example, the Malay people spread across the Malay archipelago, across the Indian ocean to Madagascar and also across the Pacific ocean, which required knowledge of the ocean currents, the winds, sailing, the movement of the stars, celestial navigation, and star maps. The star maps were not made of paper, but were lashed together with strings, sticks and shells. Their outrigger ships were ocean-worthy, thousands of years ago, well before the maritime technology of the West was capable of the age of exploration.
Before them, likely by hunting and gathering, the Australian aborigines and the Native Americans followed the contours of the continents to populate their parts of the world - a journey of tens of thousands of kilometers, and which may have taken thousands of years.
The Middle Ages: Western World
See Also: Medieval medicine, Medieval philosophy
With the loss of the Western Roman Empire, much of Europe lost contact with the knowledge of the past. Because of this regression in knowledge, the long period that followed is also known as the Dark Ages. While the Byzantine Empire still held learning centers such as Alexandria and Constantinople, Western Europes knowledge was concentrated in monasteries until the development of medieval universities in the 12th and 13th centuries. Initially these universities were organized to only teach theology, but people like Roger Bacon encouraged teaching of the sciences. Scientific teaching of the period was based upon copies of ancient texts that remained in Western Europe, and is known as the philosophic school of scholasticism. The rise of Christianity saw a strange paradox: classical Greek philosophy (along with Greek and Roman art, literature and religious iconography) was suppressed while at the same time it was safeguarded.
Renaissance Period
See Also: Renaissance
The Renaissance was instigated by rediscovery of the works of ancient philosophers and an intellectual revitalization of Europe. This provided a solid foundation for all future scientific work. Contact with the Islamic world in Sicily and Spain allowed Europeans access to preserved copies of Greek and Roman works along with the works of Islamic philosophers. Translations and commentaries of Aristotle by the Islamic scholar Averroës were influential in much of Europe. The published works of Marco Polo along with the Crusades helped spark interest in geography. Most importantly, the development of the printing press in the 1450s allowed for new ideas to be rapidly copied to multiple people.
The Middle Ages: Eastern World
See Also: Islamic science
In the Middle East, Greek philosophy was able to find some short-lived support by the newly created Arab Caliphate (Empire). With the spread of Islam in the 7th and 8th centuries, a period of Islamic scholarship 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 Roman texts from the Byzantine Empire along with Indian sources of learning provided Islamic scholars a knowledge base to build upon. In addition, there was the Hajj. This annual pilgrimage to Mecca facilitated scholarly collaboration by bringing together people and new ideas from all over the Islamic world.
In Islamic versions of early scientific method, ethics played an important role. During this period the concepts of citation and peer review were developed. Islamic scholars used previous work in medicine, astronomy and mathematics as bedrock to develop new fields like alchemy. In mathematics, the Islamic scholar Muhammad ibn Musa al-Khwarizmi gave his name to what we now call an algorithm, and the word algebra is derived from al-jabr, the beginning of the name of one of his publications in which he developed a system of solving quadratic equations. Researchers like Al-Batani (850-929) contributed to the fields of astronomy and mathematics and Al-Razi to chemistry. Examples of fruits of these contributions can be seen in Damascus steel (wootz steel), and the Baghdad Battery. Arab alchemy proved to be in inspiration to Roger Bacon, and later to Isaac Newton. Also in astronomy, Al-Batani improved the measurements of Hipparchus, preserved in the translation of the Greek Hè Megalè Syntaxis (the great treatise) translated as Almagest. About 900, Al-Batani improved the precision of the measurement of the precession of the earth's axis, thus continuing a millennium's legacy of measurements in his own land (Babylonia and Chaldea- the area now known as Iraq).
Developments in China
The solid-fuel rocket was invented in China about 1150, about 200 years after the invention of gunpowder (which was its main fuel) and 500 years after the invention of the match. At the same time that the age of exploration was occurring in the West, the Chinese emperors of the Ming Dynasty also sent ships, some reaching Africa. But the enterprises were not further funded, halting further exploration and development. When Magellan's ships reached Brunei in 1521, they found a wealthy city that had been fortified by Chinese engineers, protected by a breakwater. Antonio Pigafetta noted that much of the technology of Brunei was equal to Western technology of the time. Also, there were more cannons in Brunei than on Magellan's ships, and the Chinese merchants to the Brunei court had sold them spectacles and porcelain, which were rarities in Europe. The scientific base for these technological developments appears to be quite thin, however. For example, the concept of force was not clearly formulated in Chinese texts of the period.
The Scientific Revolution
Main article: Scientific Revolution
The birth of modern science in Europe began in a period of great upheaval. Events such as the Protestant Reformation, the discovery of the Americas by Christopher Columbus, the Fall of Constantinople, and the Spanish Inquisition caused both social and political changes to occur throughout Europe. These changes and new discoveries created an environment willing 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 also found to not always match everyday observations. An example of this is an arrow flying through the air after leaving a bow contradicts with Aristotle's assertion that the natural state of all objects is at rest. Work by Vesalius on human cadavers also found problems with the Galenian 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. Its origins can be found in the European re-discovery of Aristotle in the twelfth and thirteenth centuries. This period culminated with the publication of the Philosophiae Naturalis Principia Mathematica in 1687 by Isaac Newton (dates disputed).
The Scientific Revolution is held by most historians (e.g., Howard Margolis) to have begun in 1543, when there was brought to the Polish astronomer Nicolaus Copernicus the first printed copy of the book De Revolutionibus he had written about a dozen years earlier. The thesis of this book is that the Earth moves around the Sun. Other significant scientific advances were made during this time by Galileo Galilei, Christiaan Huygens, Johannes Kepler, and Blaise Pascal. In philosophy, major contributions were made by Francis Bacon, Sir Thomas Browne, René Descartes, and Thomas Hobbes, influencing the thinking of the time. Development of the basics of scientific method also occurred during this time. The new way of thinking emphasized experimentation and reason over traditional considerations.
Contemporary science
The Scientific Revolution led to an explosion of knowledge and the division of scientific inquiry into fields of specialty, each with its own history and prospects. This growth has been largest through the 19th and 20th century. Though science has diversified, new discoveries have given a better understanding of the world as a whole.
Natural sciences
Physics
Main article: History of physics
After Newton defined classical mechanics, the next great field of inquiry within physics was the nature of electricity. Observations in the 17th and 18th century by scientists such as Robert Boyle, Stephen Gray, and Benjamin Franklin created a foundation for later work. These observations also established our basic understanding of electrical charge and current.
In 1821, Michael Faraday integrated the study of magnetism with the study of electricity. This was done by demonstrating that a moving magnet induced an electric current in a conductor. Faraday also formulated a physical conception of (what are now called) electromagnetic fields. James Clerk Maxwell built upon this conception, in 1864, with an interlinked set of 20 equations that explained the interactions between electric and magnetic field. These 20 equations were later reduced, using vector calculus, to a set of four equations.
In addition to other electromagnetic phenomena, Maxwell's equations also can be used to describe light. Confirmation of this observation was made with the 1888 discovery of radio by Heinrich Hertz and in 1895 when Wilhelm Roentgen detected X rays. The ability to describe light in electromagnetic terms helped serve as a springboard for Albert Einstein's 1905 publication of his theory of special relativity. This theory combined classical mechanics with Maxwell's equations. Einstein built further on this by including gravity into his calculations and published his theory of general relativity in 1915.
One part of the theory of general relativity is Einstein's field equation. This describes how the mass-energy tensor creates a curvature in spacetime, and when combined with the geodesic equation forms the basis of general relativity. Further work on Einstein's field equation produced results which predicted the Big Bang, black holes, and the expanding universe. Einstein believed in a static universe and attempted to fix his equation to allow for this, but by 1927, the expanding universe was sought for by astronomers, and in 1929 evidence was found by Edwin Hubble.
Henri Becquerel accidentally discovered radioactivity in 1896. The next year Joseph J. Thomson discovered the electron. These discoveries revealed that the assumption of many physicists that atoms were the basic unit of matter was flawed, and prompted further study into the structure of atoms.
In 1900, Max Planck published his explanation of blackbody radiation. This equation assumed that radiators are quantized in nature, which proved to be the opening argument in the edifice that would become quantum mechanics.
During the 1920s Erwin Schrödinger, Werner Heisenberg, and Max Born were able to formulate a consistent picture of the chemical behavior of matter, a complete theory of the electronic structure of the atom, as a byproduct of the quantum theory. Schwinger, Tomonaga, and Richard Feynman were able to explain the Lamb shift using a quantum field theory and quantum electrodynamics by the 1940s. In 1959, Feynman presented the hypothesis that it is possible to manipulate matter at the level of atoms, starting the field of nanotechnology.
C. N. Yang and T. D. Lee, in the 1950s, discovered an unexpected asymmetry in the decay of a subatomic particleTemplate:Fn. Yang and Mills attempted to explain the particle zoo with a non-Abelian gauge field which reduced to Maxwell's equations as a special case. This was an example of the gauge theory approach to physics, now called the Standard Model, which attempts to explain all the currently known particles.
The two themes of the 20th century, general relativity and quantum mechanics, are not currently consistent with each other. General relativity describes the universe on the scale of planets and solar systems while quantum mechanics operates on sub-atomic scales. This challenge is being attacked by string theory, which treats spacetime as a manifold, not of points, but of one-dimensional objects, strings. Strings have properties like a common string (e.g., tension and vibration). The theories yield promising, but not yet testable results. The search for experimental verification of string theory is in progress.
Chemistry
Main article: History of chemistry
An important discovery in the 19th century was John Dalton's proof in 1803 that all matter is made of atoms, the smallest indestructible parts of matter. This idea had originated in ancient Greece. Dalton also formulated the law of mass relationships. In 1869, Dmitry Mendeleyev composed his periodic table of elements on the basis of Dalton's discoveries.
In 1828 the German chemist Friedrich Wöhler synthesized urea, the first time an organic compound was synthesized from inorganic material. This opened a new research field in chemistry, and by the end of the 19th century, scientists were able to synthesize hundreds of organic compounds. The most important among them are mauve, magenta, and other synthetic dyes, as well as the widely used drug aspirin. The discovery also contributed greatly to the theory of isomerism.
The later part of the nineteenth century saw the exploitation of the petrochemicals of the earth, after the exhaustion of the oil supply from whaling in the previous centuries. Systematic production of refined materials provided a ready supply of products which not only provided energy, but also synthetic materials for clothing, medicine, and everyday disposable resources, by the twentieth century.
By the twentieth century, the integration of physics and chemistry was complete, 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, culiminating in the physical modelling of the DNA molecule, in essence, the secret of life, in the words of Francis Crick. The co-discoverer of the structure of DNA, James Watson, was to treasure a gift from Crick, a copy of Pauling's book. Watson and Crick deduced the structure of DNA by physical modelling. Their helical structure was simultaneously confirmed by x-ray crystallography at William Bragg's laboratory in Cambridge. Pauling was very close to discovery as well; his hypothetical structure a triple helix rather than the double helix of DNA. In the same year, the Miller-Urey experiment demonstrated that basic constituents of DNA, simple amino acids, could themselves be built up from simpler molecules in a simulation of primordial processes on Earth.
In the mid-twentieth century, control of the electronic structure of semiconductor materials was made precise by the creation of single-crystal circuits. Advances in processing technology, like that utilized in other parts of the materials industry, coupled with the advance of optical and x-ray sources, made possible the miniaturization of electrical circuits, culminating in the integrated circuits of the twentieth century. In this way computer program logic could be realized and mechanized for computation and control.
Geology and Astronomy
Main articles: Geology, History of astronomy
In China, the polymath Shen Kua (1031 - 1095) formulated a hypothesis for the process of land formation: based on his observation of fossil shells in a geological stratum in a mountain hundreds of miles from the ocean, he inferred that the land was formed by erosion of the mountains and by deposition of silt.
The work on rocks Peri lithōn by Theophrastus, a student of Aristotle, remained authoritative for millennia. However, its interpretation of fossils was not overturned until after the Scientific Revolution. It was translated into Latin and the other languages of Europe such as French. Georg Bauer (Agricola), a physician, summarized the knowledge of mining and metallurgy 1556.
By the 1700s Jean-Etienne Guettard and Nicolas Desmarest hiked central France and recorded their observations on geological maps; Guettard recorded the first observation of the volcanic origins of this part of France. James Hutton recorded his Theory of the Earth in the 1788 Transactions of the Royal Society of Edinburgh, later called uniformitarianism.
In 1811 Georges Cuvier and Alexandre Brongniart published their explanation of the antiquity of the Earth, inspired by Cuvier's discovery of fossil elephant bones in Paris. To prove this, they formulated the principle of stratigraphic succession of the layers of the earth. They were independently anticipated by William Smith's stratigraphic studies on England and Scotland.
By 1827 Charles Lyell's Principles of Geology reiterated Hutton's uniformitarianism, which influenced the thought of Charles Darwin.
19th Century geology revolved around the question of the Earth's exact age. Estimates varied from a few 100,000 to billions of years. The most significant advance in 20th century geology has been the development of the theory of plate tectonics in the 1960s. Plate tectonic theory arose out of two separate geological observations: seafloor spreading and continental drift. The theory revolutionized the Earth sciences.
Advances in astronomy and in optical systems in the 19th century resulted in the first observation of an asteroid (Ceres) in 1801, and the discovery of Neptune in 1846. In the 1840s, the first galaxies outside our solar system were observed by (William Parsons).
George Gamow, Ralph Alpher, and Robert Herman had calculated that there should be evidence for a Big Bang in the background temperature of the universeTemplate:Fn. In 1964, Arno Penzias and Robert WilsonTemplate:Fn 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.
Biology and Medicine
Main articles: History of biology, History of medicine
Hungarian physician Ignác Fülöp Semmelweis in 1847 dramatically reduced the occurrency of puerperal fever by the simple experiment of requiring physicians to wash their hands before attending to women in childbirth. His discovery predated the germ theory of disease. However, his discoveries were not appreciated by his contemporaries and came into use only with discoveries of British surgeon Joseph Lister, who in 1865 proved the principles of antisepsis. His work is based on the very important discoveries made by French biologist Louis Pasteur. He was able to link some microorganisms with disease. This brought a revolution in medicine. He also devised one of the most important methods in preventive medicine, when in 1880 he produced the vaccine against rabies. Pasteur also invented the process of pasteurization to help prevent the spread of disease through milk and other foods.
In the 19th century the area of genetics developed, when the Austrian monk Gregor Mendel formulated his laws of inheritance published in 1866. However, his work was not recognized for a few decades afterward. The other important scientist that influenced this field was the British scientist Charles Darwin. Darwin's famous work On the Origin of Species (1859) describes natural selection, the primary mechanism for evolution. Implications of evolution on fields outside of pure science have led to both opposition and support from different parts of society.
By 1953 James Watson and Francis Crick clarified the basic structure of DNA, the genetic material for expressing life in all its formsTemplate:Fn.
Ecology
Main article: Ecology (history)
After the astronauts of Apollo 8 took a a seminal picture, Earthrise, of the Earth just visible over the Moon's horizon, it became perfectly obvious that the Earth was finite, and that its resources were therefore limited. The interconnection and interpendence of each component ecosystem meant that human beings no longer could just exploit the earth's resources, without regard for the sustainability of the ecosystems (the air, water, ground, plants and animals) of the earth.
Social Sciences
Political Science
Main article: History of political science
One of the basic requirements for a scientific community is the existence and approval of a political sponsor; in England, the Royal Society operates under the aegis of the monarchy; in the US, the National Academy of Sciences was founded by Act of Congress; etc. Otherwise, when the basic elements of knowledge were being formulated, the political rulers of the respective communities could choose to arbitrarily either support or disallow the nascent scientific communities. For example, Alhazen had to feign madness to avoid execution. The polymath Shen Kuo lost political support, and could not continue his studies until he came up with discoveries that showed his worth to the political rulers. The admiral Zheng He could not continue his voyages of exploration after the emperors withdrew their support. Another famous example was the suppression of the work of Galileo, and before him, Giordano Bruno, burned at the stake, for his statements on cosmology; by the twentieth century, Galileo would be pardoned.
Linguistics
Main article: Historical linguistics
One of the fundamental requirements for a science is a set of defined terms, as a basis for communicating knowledge. One requisite for this is the capacity for self-reflection, which requires leisure. Thus in the Chinese family of languages, it took a scholar to point out to his benefactor, an Emperor of China, that his language was tonal, by constructing a sentence with the same words, spoken with different tones, which conveyed the meanings.
Economics
Main article: History of economic thought
Modern economics was developed by Adam Smith in his An Inquiry into the Nature and Causes of the Wealth of Nations (1776). In this five book work, Smith critiqued mercantilism and instead advocated a system of free trade with division of labour. In his thesis, Smith postulated an "Invisible Hand" that large economic systems could be self regulating throught a process of enlightened self interest. Smith's work combined with contributions from David Ricardo and others forms the basis of classical economics.
Marxian economics, developed by Karl Marx, was based on the labor theory of value and assumed the value of a good was 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 a profit.
An early response to Marxian economics was made by the Austrian school. Under this school of thought, the driving force of economic development is entrepreneurship. Under this system the labor theory of value is replaced by a system of supply and demand.
In the 1920s and 1930s, John Maynard Keynes prompted a division between microeconomics and macroeconomics. Under Keynesian economics macroeconomic trends can overwhelm economic choices made by individual. Under his theories, 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. In his works, Freidman focused on using the supply and demand of money as a method of controlling economic activity. This work was later adapted in the 1970s 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, developed in the 1970s, emphasises solid microeconomics as the basis for macroeconomic growth. New Keynesian economics was created partially in response to New Classical economics, and deals with how innefficiencies in the market create a need for control by a central bank or government.
Psychology
Main article: History of 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, because in that year Wilhelm Wundt founded the first laboratory dedicated exclusively to psychological research (in Leipzig). Other important early psychologists include Hermann Ebbinghaus (a pioneer in studies on memory), Ivan Pavlov (who 'discovered' the learning process of classical conditioning, and who should be regarded as a physiologist), and Sigmund Freud. Freud's influence has been enormous, though more as cultural icon than a force in (scientific) psychology.
Sociology, anthropology
Main articles: History of sociology, History of anthropology
Sociology as a scientific discipline emerged in the early 19th century as an academic response to the challenge of modernity: as the world is becoming smaller and more integrated, people's experience of the world is increasingly atomized and dispersed. Sociologists try to understand what holds social groups together, and to develop an "antidote" to social disintegration.
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 behavior. 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.
Big Science developed even larger social structures in the scientific communities, as the respective nations came to view them as political assets. As science became globally-shared knowledge, and access to this knowledge opened up, commentators, semioticians, for example, could study the development of archetypes and other memetic themes which seem to be common to all human cultures.
To this day, both the community of scholars who search for new science, and those who comment upon this new knowledge, continue to collaborate in this fertile process.
Emerging disciplines
Communication studies
Computer science
Materials science
See also
- History of science and technology
- Philosophy and Logic
- Epistemology (Branch of philosophy concerning the nature, origin and scope of knowledge)
- History of history
- Indian science
- Science studies
- Timeline of scientific experiments
- Timeline of scientific discoveries
- Timelines of Science
- List of famous experiments
- List of scientists
- List of Nobel laureates
- List of years in science
- Philosophy of science
Notes
Template:FnbAlpher, Herman, and Gamow. Nature 162,774 (1948). Template:FnbWilson's 1978 Nobel lecture Template:FnbJames D. Watson and Francis H. Crick. "Letters to Nature: Molecular structure of Nucleic Acid." Nature 171, 737–738 (1953). Template:FnbC.S. Wu's contribution - see also the CWP, below
References
- Thomas S. Kuhn (1996). The Structure of Scientific Revolutions (3rd ed.). University of Chicago Press. ISBN 0226458075
- Howard Margolis (2002). It Started with Copernicus. New York: McGraw-Hill. ISBN 0-07-138507-X
- Joseph Needham. Science and Civilisation in China. Multiple volumes.
- Bertrand Russell (1945). A History of Western Philosophy: And Its Connection with Political and Social Circumstances from the Earliest Times to the Present Day. New York: Simon and Schuster.
- Leonard C. Bruno (1989), The Landmarks of Science. ISBN 0-8160-2137-6
External links
- A History of Science, Vols 1-4, online text
- MIT STS.002 - Toward the Scientific Revolution. From MIT OpenCourseWare, class materials for the history of science up to and including Isaac Newton.
- Contributions of 20th century Women to Physics ("CWP")
- The official site of the Nobel Foundation. Features biographies and info on Nobel laureates