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Theoretical physics

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Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain, and predict natural phenomena . This is in contrast to experimental physics , which uses experimental tools to probe these phenomena.

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142-469: The advancement of science generally depends on the interplay between experimental studies and theory . In some cases, theoretical physics adheres to standards of mathematical rigour while giving little weight to experiments and observations. For example, while developing special relativity , Albert Einstein was concerned with the Lorentz transformation which left Maxwell's equations invariant, but

284-460: A paradeigma aims to provide an audience with an illustration of a similar occurrence. This illustration is not meant to take the audience to a conclusion; however, it is used to help guide them to get there. One way of how a paradeigma is meant to guide an audience would be exemplified by the role of a personal accountant. It is not the job of a personal accountant to tell a client exactly what (and what not) to spend money on, but to aid in guiding

426-743: A working hypothesis . Science Science is a systematic discipline that builds and organises knowledge in the form of testable hypotheses and predictions about the universe. Modern science is typically divided into two or three major branches: the natural sciences (e.g., physics , chemistry , and biology ), which study the physical world ; and the behavioural sciences (e.g., economics , psychology , and sociology ), which study individuals and societies. The formal sciences (e.g., logic , mathematics, and theoretical computer science ), which study formal systems governed by axioms and rules, are sometimes described as being sciences as well; however, they are often regarded as

568-626: A "paradigm" in Kuhn's original sense. In The Structure of Scientific Revolutions , Kuhn wrote that "the successive transition from one paradigm to another via revolution is the usual developmental pattern of mature science" (p. 12). Paradigm shifts tend to appear in response to the accumulation of critical anomalies as well as in the form of the proposal of a new theory with the power to encompass both older relevant data and explain relevant anomalies. New paradigms tend to be most dramatic in sciences that appear to be stable and mature, as in physics at

710-538: A century before, were first observed . In 2019, the international collaboration Event Horizon Telescope presented the first direct image of a black hole 's accretion disc . Modern science is commonly divided into three major branches : natural science , social science , and formal science . Each of these branches comprises various specialised yet overlapping scientific disciplines that often possess their own nomenclature and expertise. Both natural and social sciences are empirical sciences , as their knowledge

852-410: A century) led to a theory of atomic structure that accounts well for the bulk properties of matter; see, for example, Brady's General Chemistry . According to P J Smith, this ability of science to back off, move sideways, and then advance is characteristic of the natural sciences, but contrasts with the position in some social sciences, notably economics. This apparent ability does not guarantee that

994-403: A certain economy and elegance (compare to mathematical beauty ), a notion sometimes called " Occam's razor " after the 13th-century English philosopher William of Occam (or Ockham), in which the simpler of two theories that describe the same matter just as adequately is preferred (but conceptual simplicity may mean mathematical complexity). They are also more likely to be accepted if they connect

1136-467: A change in how a given society goes about organizing and understanding reality. A "dominant paradigm" refers to the values, or system of thought, in a society that are most standard and widely held at a given time. Dominant paradigms are shaped both by the community's cultural background and by the context of the historical moment. Hutchin outlines some conditions that facilitate a system of thought to become an accepted dominant paradigm: The word paradigm

1278-512: A class of elements with similarities (as opposed to syntagma – a class of elements expressing relationship. ). The Merriam-Webster Online dictionary defines one usage of paradigm as "a philosophical and theoretical framework of a scientific school or discipline within which theories, laws, and generalizations and the experiments performed in support of them are formulated; broadly: a philosophical or theoretical framework of any kind ." The Oxford Dictionary of Philosophy (2008) attributes

1420-477: A client as to how money should be spent based on the client's financial goals. Anaximenes defined paradeigma as "actions that have occurred previously and are similar to, or the opposite of, those which we are now discussing". The original Greek term παράδειγμα ( paradeigma ) was used by scribes in Greek texts (such as Plato 's dialogues Timaeus [ c. 360 BCE] and Parmenides ) as one possibility for

1562-476: A discipline's core model of reality has happened in a more evolutionary manner, with individual scientists exploring the usefulness of alternatives in a way that would not be possible if they were constrained by a paradigm. Imre Lakatos suggested (as an alternative to Kuhn's formulation) that scientists actually work within research programmes . In Lakatos' sense, a research programme is a sequence of problems, placed in order of priority. This set of priorities, and

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1704-481: A discipline. Ideas on human nature, society, and economics evolved during the Enlightenment. Hume and other Scottish Enlightenment thinkers developed A Treatise of Human Nature , which was expressed historically in works by authors including James Burnett , Adam Ferguson , John Millar and William Robertson , all of whom merged a scientific study of how humans behaved in ancient and primitive cultures with

1846-411: A few of their scientific predecessors – Galileo , Kepler , Boyle , and Newton principally – as the guides to every physical and social field of the day. The 18th century saw significant advancements in the practice of medicine and physics; the development of biological taxonomy by Carl Linnaeus ; a new understanding of magnetism and electricity; and the maturation of chemistry as

1988-500: A form of protoscience and others are a form of pseudoscience . The falsification of the original theory sometimes leads to reformulation of the theory. "Thought" experiments are situations created in one's mind, asking a question akin to "suppose you are in this situation, assuming such is true, what would follow?". They are usually created to investigate phenomena that are not readily experienced in every-day situations. Famous examples of such thought experiments are Schrödinger's cat ,

2130-763: A good example. For instance: " phenomenologists " might employ ( semi- ) empirical formulas and heuristics to agree with experimental results, often without deep physical understanding . "Modelers" (also called "model-builders") often appear much like phenomenologists, but try to model speculative theories that have certain desirable features (rather than on experimental data), or apply the techniques of mathematical modeling to physics problems. Some attempt to create approximate theories, called effective theories , because fully developed theories may be regarded as unsolvable or too complicated . Other theorists may try to unify , formalise, reinterpret or generalise extant theories, or create completely new ones altogether. Sometimes

2272-423: A greater role in knowledge creation and it was not until the 19th century that many of the institutional and professional features of science began to take shape, along with the changing of "natural philosophy" to "natural science". New knowledge in science is advanced by research from scientists who are motivated by curiosity about the world and a desire to solve problems. Contemporary scientific research

2414-475: A highly stable universe where there could be little loss of resources. However, with the advent of the steam engine and the Industrial Revolution there was an increased understanding that not all forms of energy have the same energy qualities , the ease of conversion to useful work or to another form of energy. This realisation led to the development of the laws of thermodynamics , in which

2556-455: A hypothesis proves unsatisfactory it is modified or discarded. If the hypothesis survives testing, it may become adopted into the framework of a scientific theory , a validly reasoned , self-consistent model or framework for describing the behaviour of certain natural events. A theory typically describes the behaviour of much broader sets of observations than a hypothesis; commonly, a large number of hypotheses can be logically bound together by

2698-450: A long period during which no competing alternative has shown itself capable of resolving the anomaly. He also presented cases in which a dominant paradigm had withered away because its lost credibility when viewed against changes in the wider intellectual milieu. Kuhn himself did not consider the concept of paradigm as appropriate for the social sciences. He explains in his preface to The Structure of Scientific Revolutions that he developed

2840-497: A new branch of mathematics: infinite, orthogonal series . Modern theoretical physics attempts to unify theories and explain phenomena in further attempts to understand the Universe , from the cosmological to the elementary particle scale. Where experimentation cannot be done, theoretical physics still tries to advance through the use of mathematical models. Mainstream theories (sometimes referred to as central theories ) are

2982-407: A new non- teleological way. This implied a shift in the view of objects: objects were now considered as having no innate goals. Leibniz assumed that different types of things all work according to the same general laws of nature, with no special formal or final causes. During this time the declared purpose and value of science became producing wealth and inventions that would improve human lives, in

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3124-588: A paradigm can only apply to a system that is not in its final stage. Beyond its use in the physical and social sciences, Kuhn's paradigm concept has been analysed in relation to its applicability in identifying 'paradigms' with respect to worldviews at specific points in history. One example is Matthew Edward Harris' book The Notion of Papal Monarchy in the Thirteenth Century: The Idea of Paradigm in Church History . Harris stresses

3266-464: A paradigm, research programme, research tradition, and/ or professional imagery. These structures will be motivating research, providing it with an agenda, defining what is and is not anomalous evidence, and inhibiting debate with other groups that fall under the same broad disciplinary label. (A good example is provided by the contrast between Skinnerian radical behaviourism and personal construct theory (PCT) within psychology. The most significant of

3408-446: A particular discipline, its paradigm is so convincing that it normally renders even the possibility of alternatives unconvincing and counter-intuitive. Such a paradigm is opaque , appearing to be a direct view of the bedrock of reality itself, and obscuring the possibility that there might be other, alternative imageries hidden behind it. The conviction that the current paradigm is reality tends to disqualify evidence that might undermine

3550-405: A physical theory is also judged on its ability to make new predictions which can be verified by new observations. A physical theory differs from a mathematical theorem in that while both are based on some form of axioms , judgment of mathematical applicability is not based on agreement with any experimental results. A physical theory similarly differs from a mathematical theory , in the sense that

3692-458: A preference for one outcome over another. Eliminating the bias can be achieved through transparency, careful experimental design , and a thorough peer review process of the experimental results and conclusions. After the results of an experiment are announced or published, it is normal practice for independent researchers to double-check how the research was performed, and to follow up by performing similar experiments to determine how dependable

3834-456: A priori disciplines and because of this, there is disagreement on whether they constitute a science. Nevertheless, the formal sciences play an important role in the empirical sciences. Calculus , for example, was initially invented to understand motion in physics. Natural and social sciences that rely heavily on mathematical applications include mathematical physics , chemistry , biology , finance , and economics . Applied science

3976-400: A revolution in information technology and the rise of the global internet and mobile computing , including smartphones . The need for mass systematisation of long, intertwined causal chains and large amounts of data led to the rise of the fields of systems theory and computer-assisted scientific modelling . The Human Genome Project was completed in 2003 by identifying and mapping all of

4118-461: A separate discipline from philosophy when Wilhelm Wundt founded the first laboratory for psychological research in 1879. During the mid-19th century Charles Darwin and Alfred Russel Wallace independently proposed the theory of evolution by natural selection in 1858, which explained how different plants and animals originated and evolved. Their theory was set out in detail in Darwin's book On

4260-592: A separate field because they rely on deductive reasoning instead of the scientific method or empirical evidence as their main methodology. Applied sciences are disciplines that use scientific knowledge for practical purposes, such as engineering and medicine . The history of science spans the majority of the historical record, with the earliest written records of identifiable predecessors to modern science dating to Bronze Age Egypt and Mesopotamia from around 3000 to 1200 BCE . Their contributions to mathematics, astronomy , and medicine entered and shaped

4402-475: A set of basic assumptions that are needed to justify the scientific method: there is an objective reality shared by all rational observers; this objective reality is governed by natural laws ; these laws were discovered by means of systematic observation and experimentation. Mathematics is essential in the formation of hypotheses , theories , and laws, because it is used extensively in quantitative modelling, observing, and collecting measurements . Statistics

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4544-463: A set of rules. It includes mathematics, systems theory , and theoretical computer science . The formal sciences share similarities with the other two branches by relying on objective, careful, and systematic study of an area of knowledge. They are, however, different from the empirical sciences as they rely exclusively on deductive reasoning, without the need for empirical evidence, to verify their abstract concepts. The formal sciences are therefore

4686-478: A single theory. Thus, a theory is a hypothesis explaining various other hypotheses. In that vein, theories are formulated according to most of the same scientific principles as hypotheses. Scientists may generate a model , an attempt to describe or depict an observation in terms of a logical, physical or mathematical representation, and to generate new hypotheses that can be tested by experimentation. While performing experiments to test hypotheses, scientists may have

4828-429: A strong awareness of the determining forces of modernity . Modern sociology largely originated from this movement. In 1776, Adam Smith published The Wealth of Nations , which is often considered the first work on modern economics. During the nineteenth century many distinguishing characteristics of contemporary modern science began to take shape. These included the transformation of the life and physical sciences;

4970-438: A unified theory in the early 20th-century when the modern synthesis reconciled Darwinian evolution with classical genetics . Albert Einstein 's theory of relativity and the development of quantum mechanics complement classical mechanics to describe physics in extreme length , time and gravity . Widespread use of integrated circuits in the last quarter of the 20th century combined with communications satellites led to

5112-469: A wide range of phenomena. Testing the consequences of a theory is part of the scientific method . Physical theories can be grouped into three categories: mainstream theories , proposed theories and fringe theories . Theoretical physics began at least 2,300 years ago, under the Pre-socratic philosophy , and continued by Plato and Aristotle , whose views held sway for a millennium. During

5254-538: Is a distinct set of concepts or thought patterns, including theories, research methods , postulates, and standards for what constitute legitimate contributions to a field. The word paradigm is Greek in origin, meaning "pattern". Paradigm comes from Greek παράδειγμα ( paradeigma ); "pattern, example, sample"; from the verb παραδείκνυμι ( paradeiknumi ); "exhibit, represent, expose"; and that from παρά ( para ); "beside, beyond"; and δείκνυμι ( deiknumi ); "to show, to point out". In classical (Greek-based) rhetoric ,

5396-436: Is also still used to indicate a pattern or model or an outstandingly clear or typical example or archetype . The term is frequently used in this sense in the design professions. Design Paradigms or archetypes comprise functional precedents for design solutions. The best known references on design paradigms are Design Paradigms: A Sourcebook for Creative Visualization , by Wake, and Design Paradigms by Petroski. This term

5538-430: Is also used in cybernetics . Here it means (in a very wide sense) a (conceptual) protoprogram for reducing the chaotic mass to some form of order. Note the similarities to the concept of entropy in chemistry and physics. A paradigm there would be a sort of prohibition to proceed with any action that would increase the total entropy of the system. To create a paradigm requires a closed system that accepts changes. Thus

5680-502: Is an example: it is not possible to see both the rabbit and the duck simultaneously.) This is significant in relation to the issue of incommensurability (see below). An example of a currently accepted paradigm would be the standard model of physics. The scientific method allows for orthodox scientific investigations into phenomena that might contradict or disprove the standard model; however grant funding would be proportionately more difficult to obtain for such experiments, depending on

5822-425: Is apparent from his analogy between a paradigm shift and the flip-over involved in some optical illusions. However, he subsequently diluted his commitment to incommensurability considerably, partly in the light of other studies of scientific development that did not involve revolutionary change. One of the examples of incommensurability that Kuhn used was the change in the style of chemical investigations that followed

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5964-487: Is based on empirical observations and is capable of being tested for its validity by other researchers working under the same conditions. Natural science is the study of the physical world. It can be divided into two main branches: life science and physical science . These two branches may be further divided into more specialised disciplines. For example, physical science can be subdivided into physics, chemistry , astronomy , and earth science . Modern natural science

6106-439: Is becoming a central feature of computational contributions to science, for example in agent-based computational economics , random forests , topic modeling and various forms of prediction. However, machines alone rarely advance knowledge as they require human guidance and capacity to reason; and they can introduce bias against certain social groups or sometimes underperform against humans. Interdisciplinary science involves

6248-714: Is considered to be one of the most important publications in medicine and was used until the 18th century. By the eleventh century most of Europe had become Christian, and in 1088, the University of Bologna emerged as the first university in Europe. As such, demand for Latin translation of ancient and scientific texts grew, a major contributor to the Renaissance of the 12th century . Renaissance scholasticism in western Europe flourished, with experiments done by observing, describing, and classifying subjects in nature. In

6390-542: Is highly collaborative and is usually done by teams in academic and research institutions , government agencies, and companies. The practical impact of their work has led to the emergence of science policies that seek to influence the scientific enterprise by prioritising the ethical and moral development of commercial products, armaments, health care, public infrastructure, and environmental protection . The word science has been used in Middle English since

6532-464: Is now generally seen as too limited. Some examples of contemporary paradigm shifts include: Kuhn's idea was, itself, revolutionary in its time. It caused a major change in the way that academics talk about science; and, so, it may be that it caused (or was part of) a "paradigm shift" in the history and sociology of science. However, Kuhn would not recognize such a paradigm shift. Being in the social sciences, people can still use earlier ideas to discuss

6674-424: Is structured. Normal science proceeds within such a framework or paradigm. A paradigm does not impose a rigid or mechanical approach, but can be taken more or less creatively and flexibly. The Oxford English Dictionary defines a paradigm as "a pattern or model, an exemplar; a typical instance of something, an example". The historian of science Thomas Kuhn gave the word its contemporary meaning when he adopted

6816-447: Is the search for solutions to practical problems using this knowledge. Most understanding comes from basic research, though sometimes applied research targets specific practical problems. This leads to technological advances that were not previously imaginable. Scientific research involves using the scientific method , which seeks to objectively explain the events of nature in a reproducible way. Scientists usually take for granted

6958-533: Is the successor to the natural philosophy that began in Ancient Greece . Galileo , Descartes , Bacon , and Newton debated the benefits of using approaches that were more mathematical and more experimental in a methodical way. Still, philosophical perspectives, conjectures , and presuppositions , often overlooked, remain necessary in natural science. Systematic data collection, including discovery science , succeeded natural history , which emerged in

7100-427: Is the use of the scientific method and knowledge to attain practical goals and includes a broad range of disciplines such as engineering and medicine. Engineering is the use of scientific principles to invent, design and build machines, structures and technologies. Science may contribute to the development of new technologies. Medicine is the practice of caring for patients by maintaining and restoring health through

7242-403: Is used to make falsifiable predictions, which are typically posted before being tested by experimentation. Disproof of a prediction is evidence of progress. Experimentation is especially important in science to help establish causal relationships to avoid the correlation fallacy , though in some sciences such as astronomy or geology, a predicted observation might be more appropriate. When

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7384-410: Is used to summarise and analyse data, which allows scientists to assess the reliability of experimental results. In the scientific method an explanatory thought experiment or hypothesis is put forward as an explanation using parsimony principles and is expected to seek consilience  – fitting with other accepted facts related to an observation or scientific question. This tentative explanation

7526-632: The Byzantine empire and Arabic translations were done by groups such as the Nestorians and the Monophysites . Under the Caliphate , these Arabic translations were later improved and developed by Arabic scientists. By the 6th and 7th centuries, the neighbouring Sassanid Empire established the medical Academy of Gondeshapur , which is considered by Greek, Syriac, and Persian physicians as

7668-539: The EPR thought experiment , simple illustrations of time dilation , and so on. These usually lead to real experiments designed to verify that the conclusion (and therefore the assumptions) of the thought experiments are correct. The EPR thought experiment led to the Bell inequalities , which were then tested to various degrees of rigor , leading to the acceptance of the current formulation of quantum mechanics and probabilism as

7810-740: The Early Middle Ages (400 to 1000 CE), but in the Medieval renaissances ( Carolingian Renaissance , Ottonian Renaissance and the Renaissance of the 12th century ) scholarship flourished again. Some Greek manuscripts lost in Western Europe were preserved and expanded upon in the Middle East during the Islamic Golden Age , along with the later efforts of Byzantine Greek scholars who brought Greek manuscripts from

7952-609: The Proto-Italic language as * skije- or * skijo- meaning "to know", which may originate from Proto-Indo-European language as *skh 1 -ie , *skh 1 -io , meaning "to incise". The Lexikon der indogermanischen Verben proposed sciō is a back-formation of nescīre , meaning "to not know, be unfamiliar with", which may derive from Proto-Indo-European *sekH- in Latin secāre , or *skh 2 - , from *sḱʰeh2(i)- meaning "to cut". In

8094-572: The Scientific Revolution gathered pace, the concepts of matter , energy, space, time and causality slowly began to acquire the form we know today, and other sciences spun off from the rubric of natural philosophy . Thus began the modern era of theory with the Copernican paradigm shift in astronomy, soon followed by Johannes Kepler 's expressions for planetary orbits, which summarized the meticulous observations of Tycho Brahe ;

8236-561: The camera obscura and the telescope . At the start of the Renaissance, Roger Bacon , Vitello , and John Peckham each built up a scholastic ontology upon a causal chain beginning with sensation, perception, and finally apperception of the individual and universal forms of Aristotle. A model of vision later known as perspectivism was exploited and studied by the artists of the Renaissance. This theory uses only three of Aristotle's four causes: formal, material, and final. In

8378-424: The historical method , case studies , and cross-cultural studies . Moreover, if quantitative information is available, social scientists may rely on statistical approaches to better understand social relationships and processes. Formal science is an area of study that generates knowledge using formal systems . A formal system is an abstract structure used for inferring theorems from axioms according to

8520-431: The materialistic sense of having more food, clothing, and other things. In Bacon's words , "the real and legitimate goal of sciences is the endowment of human life with new inventions and riches ", and he discouraged scientists from pursuing intangible philosophical or spiritual ideas, which he believed contributed little to human happiness beyond "the fume of subtle, sublime or pleasing [speculation]". Science during

8662-499: The prevention , diagnosis , and treatment of injury or disease. The applied sciences are often contrasted with the basic sciences , which are focused on advancing scientific theories and laws that explain and predict events in the natural world. Computational science applies computing power to simulate real-world situations, enabling a better understanding of scientific problems than formal mathematics alone can achieve. The use of machine learning and artificial intelligence

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8804-487: The theory of impetus . His criticism served as an inspiration to medieval scholars and Galileo Galilei, who extensively cited his works ten centuries later. During late antiquity and the early Middle Ages , natural phenomena were mainly examined via the Aristotelian approach. The approach includes Aristotle's four causes : material, formal, moving, and final cause. Many Greek classical texts were preserved by

8946-460: The two-fluid theory of electricity are two cases in this point. However, an exception to all the above is the wave–particle duality , a theory combining aspects of different, opposing models via the Bohr complementarity principle . Physical theories become accepted if they are able to make correct predictions and no (or few) incorrect ones. The theory should have, at least as a secondary objective,

9088-406: The 13th century, medical teachers and students at Bologna began opening human bodies, leading to the first anatomy textbook based on human dissection by Mondino de Luzzi . New developments in optics played a role in the inception of the Renaissance , both by challenging long-held metaphysical ideas on perception, as well as by contributing to the improvement and development of technology such as

9230-717: The 14th century in the sense of "the state of knowing". The word was borrowed from the Anglo-Norman language as the suffix -cience , which was borrowed from the Latin word scientia , meaning "knowledge, awareness, understanding". It is a noun derivative of the Latin sciens meaning "knowing", and undisputedly derived from the Latin sciō , the present participle scīre , meaning "to know". There are many hypotheses for science ' s ultimate word origin. According to Michiel de Vaan , Dutch linguist and Indo-Europeanist , sciō may have its origin in

9372-444: The 16th century by describing and classifying plants, animals, minerals, and other biotic beings. Today, "natural history" suggests observational descriptions aimed at popular audiences. Social science is the study of human behaviour and the functioning of societies. It has many disciplines that include, but are not limited to anthropology , economics, history, human geography , political science , psychology, and sociology. In

9514-429: The 19th century. Another important event in the 19th century was the discovery of electromagnetic theory , unifying the previously separate phenomena of electricity, magnetism and light. The pillars of modern physics , and perhaps the most revolutionary theories in the history of physics, have been relativity theory and quantum mechanics . Newtonian mechanics was subsumed under special relativity and Newton's gravity

9656-633: The 3rd millennium BCE, the ancient Egyptians developed a decimal numbering system , solved practical problems using geometry , and developed a calendar . Their healing therapies involved drug treatments and the supernatural, such as prayers, incantations , and rituals. The ancient Mesopotamians used knowledge about the properties of various natural chemicals for manufacturing pottery , faience , glass, soap, metals, lime plaster , and waterproofing. They studied animal physiology , anatomy , behaviour , and astrology for divinatory purposes. The Mesopotamians had an intense interest in medicine and

9798-475: The Dutchmen Snell and Huygens. In the 18th and 19th centuries Joseph-Louis Lagrange , Leonhard Euler and William Rowan Hamilton would extend the theory of classical mechanics considerably. They picked up the interactive intertwining of mathematics and physics begun two millennia earlier by Pythagoras. Among the great conceptual achievements of the 19th and 20th centuries were the consolidation of

9940-585: The Earth ) or may be an alternative model that provides answers that are more accurate or that can be more widely applied. In the latter case, a correspondence principle will be required to recover the previously known result . Sometimes though, advances may proceed along different paths. For example, an essentially correct theory may need some conceptual or factual revisions; atomic theory , first postulated millennia ago (by several thinkers in Greece and India ) and

10082-404: The Enlightenment was dominated by scientific societies and academies , which had largely replaced universities as centres of scientific research and development. Societies and academies were the backbones of the maturation of the scientific profession. Another important development was the popularisation of science among an increasingly literate population. Enlightenment philosophers turned to

10224-601: The Greek natural philosophy of classical antiquity , whereby formal attempts were made to provide explanations of events in the physical world based on natural causes, while further advancements, including the introduction of the Hindu–Arabic numeral system , were made during the Golden Age of India . Scientific research deteriorated in these regions after the fall of the Western Roman Empire during

10366-410: The Greek philosopher Leucippus and his student Democritus . Later, Epicurus would develop a full natural cosmology based on atomism, and would adopt a "canon" (ruler, standard) which established physical criteria or standards of scientific truth. The Greek doctor Hippocrates established the tradition of systematic medical science and is known as " The Father of Medicine ". A turning point in

10508-458: The Milesian school, which was founded by Thales of Miletus and later continued by his successors Anaximander and Anaximenes , were the first to attempt to explain natural phenomena without relying on the supernatural . The Pythagoreans developed a complex number philosophy and contributed significantly to the development of mathematical science. The theory of atoms was developed by

10650-555: The Origin of Species , published in 1859. Separately, Gregor Mendel presented his paper, " Experiments on Plant Hybridization " in 1865, which outlined the principles of biological inheritance, serving as the basis for modern genetics. Early in the 19th century John Dalton suggested the modern atomic theory , based on Democritus's original idea of indivisible particles called atoms . The laws of conservation of energy , conservation of momentum and conservation of mass suggested

10792-515: The account is veridical at any one time, of course, and most modern philosophers of science are fallibilists . However, members of other disciplines do see the issue of incommensurability as a much greater obstacle to evaluations of "progress"; see, for example, Martin Slattery's Key Ideas in Sociology . Opaque Kuhnian paradigms and paradigm shifts do exist. A few years after the discovery of

10934-472: The advent of writing systems in early civilisations like Ancient Egypt and Mesopotamia , creating the earliest written records in the history of science in around 3000 to 1200 BCE . Although the words and concepts of "science" and "nature" were not part of the conceptual landscape at the time, the ancient Egyptians and Mesopotamians made contributions that would later find a place in Greek and medieval science: mathematics, astronomy, and medicine. From

11076-419: The applications of relativity to problems in astronomy and cosmology respectively . All of these achievements depended on the theoretical physics as a moving force both to suggest experiments and to consolidate results — often by ingenious application of existing mathematics, or, as in the case of Descartes and Newton (with Leibniz ), by inventing new mathematics. Fourier's studies of heat conduction led to

11218-424: The associated set of preferred techniques, is the positive heuristic of a programme. Each programme also has a negative heuristic ; this consists of a set of fundamental assumptions that – temporarily, at least – takes priority over observational evidence when the two appear to conflict. This latter aspect of research programmes is inherited from Kuhn's work on paradigms, and represents an important departure from

11360-514: The body of knowledge of both factual and scientific views and possess a usual scientific quality of the tests of repeatability, consistency with existing well-established science and experimentation. There do exist mainstream theories that are generally accepted theories based solely upon their effects explaining a wide variety of data, although the detection, explanation, and possible composition are subjects of debate. The proposed theories of physics are usually relatively new theories which deal with

11502-426: The collection of evidence. These preconceptions embody both hidden assumptions and elements that Kuhn describes as quasi-metaphysical. The interpretations of the paradigm may vary among individual scientists. Kuhn was at pains to point out that the rationale for the choice of exemplars is a specific way of viewing reality: that view and the status of "exemplar" are mutually reinforcing. For well-integrated members of

11644-398: The combination of two or more disciplines into one, such as bioinformatics , a combination of biology and computer science or cognitive sciences . The concept has existed since the ancient Greek period and it became popular again in the 20th century. Scientific research can be labelled as either basic or applied research. Basic research is the search for knowledge and applied research

11786-539: The concept of paradigm precisely to distinguish the social from the natural sciences. While visiting the Center for Advanced Study in the Behavioral Sciences in 1958 and 1959, surrounded by social scientists, he observed that they were never in agreement about the nature of legitimate scientific problems and methods. He explains that he wrote this book precisely to show that there can never be any paradigms in

11928-610: The course of tens of thousands of years, taking different forms around the world, and few details are known about the very earliest developments. Women likely played a central role in prehistoric science, as did religious rituals . Some scholars use the term " protoscience " to label activities in the past that resemble modern science in some but not all features; however, this label has also been criticised as denigrating, or too suggestive of presentism , thinking about those activities only in relation to modern categories. Direct evidence for scientific processes becomes clearer with

12070-400: The degree of deviation from the accepted standard model theory the experiment would test for. To illustrate the point, an experiment to test for the mass of neutrinos or the decay of protons (small departures from the model) is more likely to receive money than experiments that look for the violation of the conservation of momentum, or ways to engineer reverse time travel. Mechanisms similar to

12212-544: The discovery of electrostatic photography , xerography and the quartz clock . Kuhn pointed out that it could be difficult to assess whether a particular paradigm shift had actually led to progress, in the sense of explaining more facts, explaining more important facts, or providing better explanations, because the understanding of "more important", "better", etc. changed with the paradigm. The two versions of reality are thus incommensurable . Kuhn's version of incommensurability has an important psychological dimension. This

12354-505: The discovery of radioactivity by Henri Becquerel and Marie Curie in 1896, Marie Curie then became the first person to win two Nobel Prizes . In the next year came the discovery of the first subatomic particle, the electron . In the first half of the century the development of antibiotics and artificial fertilisers improved human living standards globally. Harmful environmental issues such as ozone depletion , ocean acidification , eutrophication , and climate change came to

12496-454: The dying Byzantine Empire to Western Europe at the start of the Renaissance . The recovery and assimilation of Greek works and Islamic inquiries into Western Europe from the 10th to 13th century revived " natural philosophy ", which was later transformed by the Scientific Revolution that began in the 16th century as new ideas and discoveries departed from previous Greek conceptions and traditions. The scientific method soon played

12638-596: The earliest medical prescriptions appeared in Sumerian during the Third Dynasty of Ur . They seem to have studied scientific subjects which had practical or religious applications and had little interest in satisfying curiosity. In classical antiquity , there is no real ancient analogue of a modern scientist. Instead, well-educated, usually upper-class, and almost universally male individuals performed various investigations into nature whenever they could afford

12780-399: The elementary account of how science works . According to this, science proceeds through repeated cycles of observation, induction, hypothesis-testing, etc., with the test of consistency with empirical evidence being imposed at each stage. Paradigms and research programmes allow anomalies to be set aside, where there is reason to believe that they arise from incomplete knowledge (about either

12922-474: The end of the 19th century. At that time, a statement generally attributed to physicist Lord Kelvin famously claimed, "There is nothing new to be discovered in physics now. All that remains is more and more precise measurement." Five years later, Albert Einstein published his paper on special relativity , which challenged the set of rules laid down by Newtonian mechanics , which had been used to describe force and motion for over two hundred years. In this case,

13064-403: The following description of the term in the history and philosophy of science to Thomas Kuhn 's 1962 work The Structure of Scientific Revolutions : Kuhn suggests that certain scientific works, such as Newton's Principia or John Dalton's New System of Chemical Philosophy (1808), provide an open-ended resource: a framework of concepts, results, and procedures within which subsequent work

13206-462: The free energy of the universe is seen as constantly declining: the entropy of a closed universe increases over time. The electromagnetic theory was established in the 19th century by the works of Hans Christian Ørsted , André-Marie Ampère , Michael Faraday , James Clerk Maxwell , Oliver Heaviside , and Heinrich Hertz . The new theory raised questions that could not easily be answered using Newton's framework. The discovery of X-rays inspired

13348-425: The frequent use of precision instruments; the emergence of terms such as "biologist", "physicist", and "scientist"; an increased professionalisation of those studying nature; scientists gaining cultural authority over many dimensions of society; the industrialisation of numerous countries; the thriving of popular science writings; and the emergence of science journals. During the late 19th century, psychology emerged as

13490-530: The genes of the human genome . The first induced pluripotent human stem cells were made in 2006, allowing adult cells to be transformed into stem cells and turn into any cell type found in the body. With the affirmation of the Higgs boson discovery in 2013, the last particle predicted by the Standard Model of particle physics was found. In 2015, gravitational waves , predicted by general relativity

13632-431: The heliocentric model. The printing press was widely used to publish scholarly arguments, including some that disagreed widely with contemporary ideas of nature. Francis Bacon and René Descartes published philosophical arguments in favour of a new type of non-Aristotelian science. Bacon emphasised the importance of experiment over contemplation, questioned the Aristotelian concepts of formal and final cause, promoted

13774-415: The highest order, writing Principia Mathematica . In it contained a grand synthesis of the work of Copernicus, Galileo and Kepler; as well as Newton's theories of mechanics and gravitation, which held sway as worldviews until the early 20th century. Simultaneously, progress was also made in optics (in particular colour theory and the ancient science of geometrical optics ), courtesy of Newton, Descartes and

13916-562: The history of early philosophical science was Socrates ' example of applying philosophy to the study of human matters, including human nature, the nature of political communities, and human knowledge itself. The Socratic method as documented by Plato 's dialogues is a dialectic method of hypothesis elimination: better hypotheses are found by steadily identifying and eliminating those that lead to contradictions. The Socratic method searches for general commonly-held truths that shape beliefs and scrutinises them for consistency. Socrates criticised

14058-479: The history of science. Perhaps the greatest barrier to a paradigm shift, in some cases, is the reality of paradigm paralysis : the inability or refusal to see beyond the current models of thinking. This is similar to what psychologists term confirmation bias and the Semmelweis reflex . Examples include rejection of Aristarchus of Samos' , Copernicus ', and Galileo 's theory of a heliocentric solar system,

14200-455: The idea of energy (as well as its global conservation) by the inclusion of heat , electricity and magnetism , and then light . The laws of thermodynamics , and most importantly the introduction of the singular concept of entropy began to provide a macroscopic explanation for the properties of matter. Statistical mechanics (followed by statistical physics and Quantum statistical mechanics ) emerged as an offshoot of thermodynamics late in

14342-426: The idea of "social paradigm" in the context of social sciences. He identified the basic components of a social paradigm. Like Kuhn, Handa addressed the issue of changing paradigm; the process popularly known as " paradigm shift ". In this respect, he focused on social circumstances that precipitate such a shift and the effects of the shift on social institutions, including the institution of education. This broad shift in

14484-557: The idea that science should study the laws of nature and the improvement of all human life. Descartes emphasised individual thought and argued that mathematics rather than geometry should be used to study nature. At the start of the Age of Enlightenment , Isaac Newton formed the foundation of classical mechanics by his Philosophiæ Naturalis Principia Mathematica , greatly influencing future physicists. Gottfried Wilhelm Leibniz incorporated terms from Aristotelian physics , now used in

14626-675: The late 1920s. In the aftermath of World War 2, more progress brought much renewed interest in QFT, which had since the early efforts, stagnated. The same period also saw fresh attacks on the problems of superconductivity and phase transitions, as well as the first applications of QFT in the area of theoretical condensed matter. The 1960s and 70s saw the formulation of the Standard model of particle physics using QFT and progress in condensed matter physics (theoretical foundations of superconductivity and critical phenomena , among others ), in parallel to

14768-514: The late 20th century active recruitment of women and elimination of sex discrimination greatly increased the number of women scientists, but large gender disparities remained in some fields. The discovery of the cosmic microwave background in 1964 led to a rejection of the steady-state model of the universe in favour of the Big Bang theory of Georges Lemaître . The century saw fundamental changes within science disciplines. Evolution became

14910-533: The many ways these two sub-disciplines of psychology differ concerns meanings and intentions. In PCT, they are seen as the central concern of psychology; in radical behaviourism, they are not scientific evidence at all, as they cannot be directly observed.) Such considerations explain the conflict between the Kuhn/ Dogan view, and the views of others (including Larry Laudan, see above), who do apply these concepts to social sciences. Handa, M.L. (1986) introduced

15052-432: The mirror-neurons that provide a hard-wired basis for the human capacity for empathy, the scientists involved were unable to identify the incidents that had directed their attention to the issue. Over the course of the investigation, their language and metaphors had changed so that they themselves could no longer interpret all of their own earlier laboratory notes and records. However, many instances exist in which change in

15194-503: The model or the pattern that the demiurge supposedly used to create the cosmos. The English-language term paradigm has technical meanings in the fields of grammar (as applied, for example, to declension and conjugation – the 1900 Merriam-Webster dictionary defines the technical use of paradigm only in the context of grammar) and of rhetoric (as a term for an illustrative parable or fable ). In linguistics , Ferdinand de Saussure (1857–1913) used paradigm to refer to

15336-626: The most important medical center of the ancient world. The House of Wisdom was established in Abbasid -era Baghdad , Iraq , where the Islamic study of Aristotelianism flourished until the Mongol invasions in the 13th century. Ibn al-Haytham , better known as Alhazen, used controlled experiments in his optical study. Avicenna 's compilation of the Canon of Medicine , a medical encyclopaedia,

15478-414: The new paradigm reduces the old to a special case in the sense that Newtonian mechanics is still a good model for approximation for speeds that are slow compared to the speed of light . Many philosophers and historians of science, including Kuhn himself, ultimately accepted a modified version of Kuhn's model, which synthesizes his original view with the gradualist model that preceded it. Kuhn's original model

15620-672: The notion that the only function of the eye is perception, and shifted the main focus in optics from the eye to the propagation of light. Kepler is best known, however, for improving Copernicus' heliocentric model through the discovery of Kepler's laws of planetary motion . Kepler did not reject Aristotelian metaphysics and described his work as a search for the Harmony of the Spheres . Galileo had made significant contributions to astronomy, physics and engineering. However, he became persecuted after Pope Urban VIII sentenced him for writing about

15762-450: The older type of study of physics as too purely speculative and lacking in self-criticism . Aristotle in the 4th century BCE created a systematic program of teleological philosophy. In the 3rd century BCE, Greek astronomer Aristarchus of Samos was the first to propose a heliocentric model of the universe, with the Sun at the centre and all the planets orbiting it. Aristarchus's model

15904-443: The original Kuhnian paradigm have been invoked in various disciplines other than the philosophy of science. These include: the idea of major cultural themes, worldviews (and see below), ideologies , and mindsets . They have somewhat similar meanings that apply to smaller and larger scale examples of disciplined thought. In addition, Michel Foucault used the terms episteme and discourse , mathesis, and taxinomia, for aspects of

16046-457: The paradigm itself; this in turn leads to a build-up of unreconciled anomalies. It is the latter that is responsible for the eventual revolutionary overthrow of the incumbent paradigm, and its replacement by a new one. Kuhn used the expression paradigm shift (see below) for this process, and likened it to the perceptual change that occurs when our interpretation of an ambiguous image "flips over" from one state to another. (The rabbit-duck illusion

16188-611: The past, science was a synonym for "knowledge" or "study", in keeping with its Latin origin. A person who conducted scientific research was called a "natural philosopher" or "man of science". In 1834, William Whewell introduced the term scientist in a review of Mary Somerville 's book On the Connexion of the Physical Sciences , crediting it to "some ingenious gentleman" (possibly himself). Science has no single origin. Rather, systematic methods emerged gradually over

16330-480: The physical sciences and in historical organisations such as the Church is that the former, unlike the latter, requires technical expertise rather than repeating statements. In other words, after scientific training through what Kuhn calls ' exemplars ', one could not genuinely believe that, to take a trivial example, the earth is flat , whereas thinkers such as Giles of Rome in the thirteenth century wrote in favour of

16472-422: The pope, then could easily write similarly glowing things about the king. A writer such as Giles would have wanted a good job from the pope; he was a papal publicist. However, Harris writes that 'scientific group membership is not concerned with desire, emotions, gain, loss and any idealistic notions concerning the nature and destiny of humankind...but simply to do with aptitude, explanation, [and] cold description of

16614-434: The primarily sociological importance of paradigms, pointing towards Kuhn's second edition of The Structure of Scientific Revolutions . Although obedience to popes such as Innocent III and Boniface VIII was widespread, even written testimony from the time showing loyalty to the pope does not demonstrate that the writer had the same worldview as the Church, and therefore pope, at the centre. The difference between paradigms in

16756-419: The process of becoming established and some proposed theories. It can include speculative sciences. This includes physics fields and physical theories presented in accordance with known evidence, and a body of associated predictions have been made according to that theory. Some fringe theories go on to become a widely accepted part of physics. Other fringe theories end up being disproven. Some fringe theories are

16898-573: The public's attention and caused the onset of environmental studies . During this period scientific experimentation became increasingly larger in scale and funding . The extensive technological innovation stimulated by World War I , World War II , and the Cold War led to competitions between global powers , such as the Space Race and nuclear arms race . Substantial international collaborations were also made, despite armed conflicts. In

17040-425: The relation between the length of a vibrating string and the musical tone it produces. Other examples include entropy as a measure of the uncertainty regarding the positions and motions of unseen particles and the quantum mechanical idea that ( action and) energy are not continuously variable. Theoretical physics consists of several different approaches. In this regard, theoretical particle physics forms

17182-446: The results might be. Taken in its entirety, the scientific method allows for highly creative problem solving while minimising the effects of subjective and confirmation bias . Intersubjective verifiability , the ability to reach a consensus and reproduce results, is fundamental to the creation of all scientific knowledge. Paradigm In science and philosophy , a paradigm ( / ˈ p ær ə d aɪ m / PARR -ə-dyme )

17324-607: The rise of medieval universities , the only acknowledged intellectual disciplines were the seven liberal arts of the Trivium like grammar , logic , and rhetoric and of the Quadrivium like arithmetic , geometry , music and astronomy . During the Middle Ages and Renaissance , the concept of experimental science, the counterpoint to theory, began with scholars such as Ibn al-Haytham and Francis Bacon . As

17466-498: The sciences as going through alternating periods of normal science , when an existing model of reality dominates a protracted period of puzzle-solving, and revolution , when the model of reality itself undergoes sudden drastic change. Paradigms have two aspects. Firstly, within normal science, the term refers to the set of exemplary experiments that are likely to be copied or emulated. Secondly, underpinning this set of exemplars are shared preconceptions, made prior to – and conditioning –

17608-453: The seminal encyclopaedia Natural History . Positional notation for representing numbers likely emerged between the 3rd and 5th centuries CE along Indian trade routes. This numeral system made efficient arithmetic operations more accessible and would eventually become standard for mathematics worldwide. Due to the collapse of the Western Roman Empire , the 5th century saw an intellectual decline and knowledge of Greek conceptions of

17750-525: The sixteenth century Nicolaus Copernicus formulated a heliocentric model of the Solar System, stating that the planets revolve around the Sun, instead of the geocentric model where the planets and the Sun revolve around the Earth. This was based on a theorem that the orbital periods of the planets are longer as their orbs are farther from the centre of motion, which he found not to agree with Ptolemy's model. Johannes Kepler and others challenged

17892-468: The social arena, in turn, changes the way the individual perceives reality. Another use of the word paradigm is in the sense of " worldview ". For example, in social science, the term is used to describe the set of experiences, beliefs and values that affect the way an individual perceives reality and responds to that perception. Social scientists have adopted the Kuhnian phrase "paradigm shift" to denote

18034-434: The social sciences in his essay, particularly in sociology, political science and political anthropology. However, both Kuhn's original work and Dogan's commentary are directed at disciplines that are defined by conventional labels (such as "sociology"). While it is true that such broad groupings in the social sciences are usually not based on a Kuhnian paradigm, each of the competing sub-disciplines may still be underpinned by

18176-405: The social sciences, there are many competing theoretical perspectives, many of which are extended through competing research programs such as the functionalists , conflict theorists , and interactionists in sociology. Due to the limitations of conducting controlled experiments involving large groups of individuals or complex situations, social scientists may adopt other research methods such as

18318-480: The social sciences. Mattei Dogan , a French sociologist, in his article "Paradigms in the Social Sciences", develops Kuhn's original thesis that there are no paradigms at all in the social sciences since the concepts are polysemic , involving the deliberate mutual ignorance between scholars and the proliferation of schools in these disciplines. Dogan provides many examples of the non-existence of paradigms in

18460-484: The study of physics which include scientific approaches, means for determining the validity of models and new types of reasoning used to arrive at the theory. However, some proposed theories include theories that have been around for decades and have eluded methods of discovery and testing. Proposed theories can include fringe theories in the process of becoming established (and, sometimes, gaining wider acceptance). Proposed theories usually have not been tested. In addition to

18602-399: The substantive topic, or some aspect of the theories implicitly used in making observations). Larry Laudan has also made two important contributions to the debate. Laudan believed that something akin to paradigms exist in the social sciences (Kuhn had contested this, see below); he referred to these as research traditions . Laudan noted that some anomalies become "dormant", if they survive

18744-472: The theories like those listed below, there are also different interpretations of quantum mechanics , which may or may not be considered different theories since it is debatable whether they yield different predictions for physical experiments, even in principle. For example, AdS/CFT correspondence , Chern–Simons theory , graviton , magnetic monopole , string theory , theory of everything . Fringe theories include any new area of scientific endeavor in

18886-476: The time. Before the invention or discovery of the concept of phusis or nature by the pre-Socratic philosophers , the same words tend to be used to describe the natural "way" in which a plant grows, and the "way" in which, for example, one tribe worships a particular god. For this reason, it is claimed that these men were the first philosophers in the strict sense and the first to clearly distinguish "nature" and "convention". The early Greek philosophers of

19028-538: The vision provided by pure mathematical systems can provide clues to how a physical system might be modeled; e.g., the notion, due to Riemann and others, that space itself might be curved. Theoretical problems that need computational investigation are often the concern of computational physics . Theoretical advances may consist in setting aside old, incorrect paradigms (e.g., aether theory of light propagation, caloric theory of heat, burning consisting of evolving phlogiston , or astronomical bodies revolving around

19170-462: The word "theory" has a different meaning in mathematical terms. R i c = k g {\displaystyle \mathrm {Ric} =kg} The equations for an Einstein manifold , used in general relativity to describe the curvature of spacetime A physical theory involves one or more relationships between various measurable quantities. Archimedes realized that a ship floats by displacing its mass of water, Pythagoras understood

19312-449: The word to refer to the set of concepts and practices that define a scientific discipline at any particular period of time . In his book, The Structure of Scientific Revolutions (first published in 1962), Kuhn defines a scientific paradigm as: "universally recognized scientific achievements that, for a time, provide model problems and solutions to a community of practitioners, i.e., In The Structure of Scientific Revolutions , Kuhn saw

19454-463: The work of Lavoisier on atomic theory in the late 18th century. In this change, the focus had shifted from the bulk properties of matter (such as hardness, colour, reactivity, etc.) to studies of atomic weights and quantitative studies of reactions. He suggested that it was impossible to make the comparison needed to judge which body of knowledge was better or more advanced. However, this change in research style (and paradigm) eventually (after more than

19596-530: The works of these men (alongside Galileo's) can perhaps be considered to constitute the Scientific Revolution. The great push toward the modern concept of explanation started with Galileo , one of the few physicists who was both a consummate theoretician and a great experimentalist . The analytic geometry and mechanics of Descartes were incorporated into the calculus and mechanics of Isaac Newton , another theoretician/experimentalist of

19738-484: The world deteriorated in Western Europe. During the period, Latin encyclopaedists such as Isidore of Seville preserved the majority of general ancient knowledge. In contrast, because the Byzantine Empire resisted attacks from invaders, they were able to preserve and improve prior learning. John Philoponus , a Byzantine scholar in the 500s, started to question Aristotle's teaching of physics, introducing

19880-551: Was apparently uninterested in the Michelson–Morley experiment on Earth 's drift through a luminiferous aether . Conversely, Einstein was awarded the Nobel Prize for explaining the photoelectric effect , previously an experimental result lacking a theoretical formulation. A physical theory is a model of physical events. It is judged by the extent to which its predictions agree with empirical observations. The quality of

20022-422: Was given a kinematic explanation by general relativity . Quantum mechanics led to an understanding of blackbody radiation (which indeed, was an original motivation for the theory) and of anomalies in the specific heats of solids — and finally to an understanding of the internal structures of atoms and molecules . Quantum mechanics soon gave way to the formulation of quantum field theory (QFT), begun in

20164-511: Was widely rejected because it was believed to violate the laws of physics, while Ptolemy's Almagest , which contains a geocentric description of the Solar System , was accepted through the early Renaissance instead. The inventor and mathematician Archimedes of Syracuse made major contributions to the beginnings of calculus . Pliny the Elder was a Roman writer and polymath, who wrote

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