View source for Natural science

{{Short description|Branch of science about the natural world}}
{{Other uses}}
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| footer            = The natural sciences seek to understand how the world and [[universe]] around us works. There are five major branches, indicated by the photos above taken clockwise from top left: [[astronomy]], [[chemistry]], [[Earth science]], [[biology]], and [[physics]].
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{{Science|expanded=Branches}}

'''Natural science''' or '''empirical science''' is a branch of science concerned with the description, understanding, and prediction of natural phenomena, based on [[empirical evidence]] from observation and experimentation.<ref>{{cite web|url=https://www.uopeople.edu/blog/what-is-natural-science-5-definitions/|title=Definitions of the Natural Science|website=uopeople.edu|date=10 June 2021|access-date=27 December 2022|archive-date=27 December 2022|archive-url=https://web.archive.org/web/20221227073210/https://www.uopeople.edu/blog/what-is-natural-science-5-definitions/|url-status=live}}</ref> Mechanisms such as [[peer review]] and [[reproducibility]] of findings are used to try to ensure the validity of scientific advances.

Natural science can be divided into two main branches: [[list of life sciences|life science]] and [[Outline of physical science|physical science]]. Life science is alternatively known as [[biology]]. Physical science is subdivided into [[physics]], [[astronomy]], [[Earth science]], and [[chemistry]]. These branches of natural science may be further divided into more specialized branches, also known as fields. As empirical sciences, natural sciences use tools from the [[formal science]]s, such as [[mathematics]] and [[logic]], converting information about nature into measurements that can be explained as clear statements of the "[[laws of science|laws of nature]]".{{sfn|Lagemaat|2006|p=283}}

Modern natural science succeeded more classical approaches to [[natural philosophy]]. [[Galileo Galilei]], [[Johannes Kepler]], [[René Descartes]], [[Francis Bacon]], and [[Isaac Newton]] debated the benefits of a more [[mathematical physics|mathematical]] as against a more experimental method in investigating nature. Still, philosophical perspectives, [[conjecture]]s, and [[presupposition]]s, often overlooked, remain necessary in natural science.<ref>{{Cite book |last=Gauch |first=Hugh G. |url=https://books.google.com/books?id=iVkugqNG9dAC&pg=PA71 |title=Scientific Method in Practice |date=2003 |publisher=Cambridge University Press |isbn=978-0-521-01708-4 |pages=71–73 |language=en |access-date=2015-07-02 |archive-date=2023-12-13 |archive-url=https://web.archive.org/web/20231213102802/https://books.google.com/books?id=iVkugqNG9dAC&pg=PA71#v=onepage&q&f=false |url-status=live }}</ref> Systematic data collection, including [[discovery science]], succeeded [[natural history]], which emerged in the 16th century by describing and classifying plants, animals, minerals, and so on.{{sfn|Oglivie|2008|pp=1–2}} Today, "natural history" suggests observational descriptions aimed at popular audiences.<ref name="Wordnet definition">{{cite web|title=Natural History|url=http://wordnetweb.princeton.edu/perl/webwn?s=natural+history|publisher=Princeton University WordNet|access-date=October 21, 2012|url-status=live|archive-url=https://web.archive.org/web/20120303173506/http://wordnetweb.princeton.edu/perl/webwn?s=natural+history|archive-date=March 3, 2012}}</ref>

==Criteria==
{{Unsourced section|date=August 2024}}
{{main|Philosophy of science}}
Philosophers of science have suggested several criteria, including [[Karl Popper]]'s controversial [[falsifiability]] criterion, to help them differentiate scientific endeavors from non-scientific ones.<ref>{{Cite web |title=Criterion of falsifiability {{!}} Falsificationism, Popper, Hypotheses {{!}} Britannica |url=https://www.britannica.com/topic/criterion-of-falsifiability |access-date=2025-09-12 |website=www.britannica.com |language=en}}</ref><ref>{{Cite journal |last=Thornton |first=Stephen |date=1997-11-13 |title=Karl Popper |url=https://plato.stanford.edu/archivES/FALL2017/Entries/popper/}}</ref> [[Validity (statistics)|Validity]], accuracy, and quality control, such as [[peer review]] and [[reproducibility]] of findings, are amongst the most respected criteria in today's global scientific community.<ref>{{Cite journal |last=Fidler |first=Fiona |last2=Wilcox |first2=John |date=2018-12-03 |title=Reproducibility of Scientific Results |url=https://plato.stanford.edu/ENTRIES/scientific-reproducibility/index.html |language=en}}</ref><ref>{{Cite journal |last=Gundersen |first=Odd Erik |date=2021-03-29 |title=The fundamental principles of reproducibility |url=https://royalsocietypublishing.org/doi/full/10.1098/rsta.2020.0210 |journal=Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |volume=379 |issue=2197 |article-number=20200210 |doi=10.1098/rsta.2020.0210|arxiv=2011.10098 }}</ref>

In natural science, [[proof of impossibility|impossibility assertions]] come to be widely accepted as overwhelmingly probable rather than considered proven to the point of being unchallengeable. The basis for this strong acceptance is a combination of extensive evidence of something not occurring, combined with an underlying theory, very successful in making predictions, whose assumptions lead logically to the conclusion that something is impossible. While an impossibility assertion in natural science can never be proved, it could be refuted by the observation of a single counterexample. Such a counterexample would require that the assumptions underlying the theory that implied the impossibility be re-examined.

==Branches of natural science==
{{Outline|Outline of natural science}}
{{unreferenced section|date=October 2019}}

===Biology===
{{Main|Biology|Outline of biology#Branches of biology}}
[[File:Wilson1900Fig2.jpg|thumb|Onion (''[[Allium]]'') cells in different phases of the cell cycle. Growth in an '[[organism]]' is carefully controlled by regulating the cell cycle.]]
This field encompasses a diverse set of disciplines that examine phenomena related to living organisms. The scale of study can range from sub-component [[biophysics]] up to complex [[ecology|ecologies]]. Biology is concerned with the characteristics, [[scientific classification|classification]] and [[behaviors]] of [[organism]]s, as well as how [[species]] were formed and their interactions with each other and the [[environment (biophysical)|environment]].

The biological fields of [[botany]], [[zoology]], and [[medicine]] date back to early periods of civilization, while [[microbiology]] was introduced in the 17th century with the invention of the microscope. However, it was not until the 19th century that biology became a unified science. Once scientists discovered commonalities between all living things, it was decided they were best studied as a whole.

Some key developments in biology were the discovery of [[genetics]], [[evolution]] through [[natural selection]], the [[germ theory of disease]], and the application of the techniques of [[biochemistry|chemistry]] and [[biophysics|physics]] at the level of the [[cell (biology)|cell]] or [[organic molecule]].

Modern biology is divided into subdisciplines by the type of organism and by the scale being studied. [[Molecular biology]] is the study of the fundamental chemistry of life, while [[cellular biology]] is the examination of the cell; the basic building block of all life. At a higher level, [[anatomy]] and [[physiology]] look at the internal structures, and their functions, of an organism, while [[ecology]] looks at how various organisms interrelate.

===Earth science===
{{Main|Earth science|Outline of Earth sciences#Branches of Earth science}}
Earth science (also known as geoscience) is an all-embracing term for the sciences related to the planet [[Earth (planet)|Earth]], including [[geology]], [[geography]], [[geophysics]], [[geochemistry]], [[climatology]], [[glaciology]], [[hydrology]], [[meteorology]] and [[oceanography]].

Although [[mining]] and [[gemology|precious stones]] have been human interests throughout the history of civilization, the development of the related sciences of [[economic geology]] and [[mineralogy]] did not occur until the 18th century. The study of the earth, particularly [[paleontology]], blossomed in the 19th century. The growth of other disciplines, such as [[geophysics]], in the 20th century led to the development of the theory of [[plate tectonics]] in the 1960s, which has had a similar effect on the Earth sciences as the theory of evolution had on biology. Earth sciences today are closely linked to [[petroleum]] and [[mineral resource]]s, [[climate]] research, and to [[environmental assessment]] and [[environmental remediation|remediation]].

====Atmospheric sciences====
{{Main|Atmospheric sciences}}
Although sometimes considered in conjunction with the earth sciences, due to the independent development of its concepts, techniques, and practices and also the fact of it having a wide range of sub-disciplines under its wing, [[atmospheric science]] is also considered a separate branch of natural science. This field studies the characteristics of different layers of the atmosphere from ground level to the edge of the space. The timescale of the study also varies from day to century. Sometimes, the field also includes the study of climatic patterns on planets other than Earth.<ref>{{cite web |url=https://scienceandtechnology.jpl.nasa.gov/research/research-topics-list/planetary-sciences/planetary-exoplanetary-atmospheres |title=Planetary & Exoplanetary Atmospheres |author=<!--Not stated--> |date= |website=Jet Propulsion Laboratory |publisher=National Aeronautic Space Administration |access-date=9 November 2023 |quote= |archive-date=9 November 2023 |archive-url=https://web.archive.org/web/20231109012435/https://scienceandtechnology.jpl.nasa.gov/research/research-topics-list/planetary-sciences/planetary-exoplanetary-atmospheres |url-status=live }}</ref>

====Oceanography====
{{Main|Oceanography}}
The serious study of oceans began in the early- to mid-20th century. As a field of natural science, it is relatively young, but stand-alone programs offer specializations in the subject. Though some controversies remain as to the categorization of the field under earth sciences, interdisciplinary sciences, or as a separate field in its own right, most modern workers in the field agree that it has matured to a state that it has its own paradigms and practices.

====Planetary science====
{{Main|Planetary science}}
{{Expand section|date=July 2021}}

[[Planetary science]] or planetology, is the scientific study of planets, which include [[terrestrial planets]] like the Earth, and other types of planets, such as [[gas giants]] and [[ice giant]]s. Planetary science also concerns other celestial bodies, such as [[dwarf planet]]s [[moons]], [[asteroids]], and [[comets]]. This largely includes the [[Solar System]], but recently has started to expand to [[exoplanets]], particularly terrestrial [[exoplanets]]. It explores various objects, spanning from micrometeoroids to gas giants, to establish their composition, movements, genesis, interrelation, and past. Planetary science is an interdisciplinary domain, having originated from [[astronomy]] and [[Earth science]], and currently encompassing a multitude of areas, such as [[planetary geology]], [[cosmochemistry]], [[atmospheric science]], [[physics]], [[oceanography]], [[hydrology]], [[theoretical planetology]], [[glaciology]], and exoplanetology. Related fields encompass [[space physics]], which delves into the impact of the Sun on the bodies in the Solar System, and [[astrobiology]].

Planetary science comprises interconnected observational and theoretical branches. Observational research entails a combination of [[space exploration]], primarily through robotic spacecraft missions utilizing [[remote sensing]], and comparative experimental work conducted in Earth-based laboratories. The theoretical aspect involves extensive [[mathematical model]]ling and [[computer simulation]].

Typically, planetary scientists are situated within astronomy and physics or Earth sciences departments in universities or research centers. However, there are also dedicated planetary science institutes worldwide. Generally, individuals pursuing a career in planetary science undergo graduate-level studies in one of the Earth sciences, astronomy, astrophysics, geophysics, or physics. They then focus their research within the discipline of planetary science. Major conferences are held annually, and numerous [[academic journal|peer reviewed journals]] cater to the diverse research interests in planetary science. Some planetary scientists are employed by private research centers and frequently engage in collaborative research initiatives.

===Chemistry===
{{Main|Chemistry|Outline of chemistry#Branches of chemistry}}
[[File:Caffeine.svg|thumb|This [[structural formula]] for molecule [[caffeine]] shows a graphical representation of how the atoms are arranged.]]
Constituting the scientific study of matter at the [[atom]]ic and [[molecule|molecular]] scale, chemistry deals primarily with collections of atoms, such as [[gas]]es, molecules, [[crystal]]s, and [[metal]]s. The composition, statistical properties, transformations, and reactions of these materials are studied. Chemistry also involves understanding the properties and interactions of individual atoms and molecules for use in larger-scale applications.

Most chemical processes can be studied directly in a laboratory, using a series of (often well-tested) techniques for manipulating materials, as well as an understanding of the underlying processes. Chemistry is often called "[[the central science]]" because of its role in connecting the other natural sciences.

Early experiments in chemistry had their roots in the system of [[alchemy]], a set of beliefs combining mysticism with physical experiments. The science of chemistry began to develop with the work of [[Robert Boyle]], the discoverer of [[Gas|gases]], and [[Antoine Lavoisier]], who developed the theory of the [[conservation of mass]].

The [[Discoveries of the chemical elements|discovery of the chemical elements]] and [[atomic theory]] began to systematize this science, and researchers developed a fundamental understanding of [[State of matter|states of matter]], [[ion]]s, [[chemical bond]]s and [[chemical reaction]]s. The success of this science led to a complementary [[chemical industry]] that now plays a significant role in the world economy.

===Physics===
{{Main|Physics|Outline of physics#Branches of physics}}
[[File:HAtomOrbitals.png|thumb|The [[Atomic orbital|orbitals]] of the [[hydrogen atom]] are descriptions of the [[probability distribution]]s of an [[electron]] [[bound state|bound]] to a [[proton]]. Their mathematical descriptions are standard problems in [[quantum mechanics]], an important branch of physics.]]
Physics embodies the study of the fundamental constituents of the [[universe]], the [[forces]] and interactions they exert on one another, and the results produced by these interactions. Physics is generally regarded as foundational because all other natural sciences use and obey the field's principles and laws. Physics relies heavily on [[mathematics]] as the logical framework for formulating and quantifying principles.

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

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

===Astronomy===
{{Main|Astronomy|Outline of astronomy#Branches of astronomy}}

Astronomy is a natural science that studies celestial objects and phenomena. Objects of interest include planets, moons, stars, nebulae, galaxies, and comets. Astronomy is the study of everything in the universe beyond Earth's atmosphere, including objects we can see with our naked eyes. It is one of the oldest sciences.

Astronomers of early civilizations performed methodical observations of the night sky, and astronomical artifacts have been found from much earlier periods. There are two types of astronomy: observational astronomy and theoretical astronomy. Observational astronomy is focused on acquiring and analyzing data, mainly using basic principles of physics. In contrast, Theoretical astronomy is oriented towards developing computer or analytical models to describe astronomical objects and phenomena.

[[File: Moon Dedal crater.jpg|thumb|Uncrewed and crewed spacecraft missions have been used to image distant locations within the [[Solar System]], such as this [[Apollo 11]] view of [[Daedalus (crater)|Daedalus crater]] on the [[far side of the Moon]].]]
This discipline is the science of [[Astronomical object|celestial objects]] and [[phenomenon|phenomena]] that originate outside the [[Atmosphere of Earth|Earth's atmosphere]]. It is concerned with the evolution, [[physics]], [[chemistry]], [[meteorology]], [[geology]], and [[motion (physics)|motion]] of celestial objects, as well as the [[physical cosmology|formation and development of the universe]].

Astronomy includes examining, studying, and modeling stars, planets, and comets. Most of the information used by astronomers is gathered by remote observation. However, some laboratory reproduction of celestial phenomena has been performed (such as the molecular chemistry of the [[interstellar medium]]). There is considerable overlap with [[physics]] and in some areas of [[earth science]]. There are also interdisciplinary fields such as [[astrophysics]], [[planetary sciences]], and [[cosmology]], along with allied disciplines such as [[space physics]] and [[astrochemistry]].

While the study of celestial features and phenomena can be traced back to antiquity, the scientific methodology of this field began to develop in the middle of the 17th century. A key factor was [[Galileo Galilei|Galileo]]'s introduction of the telescope to examine the night sky in more detail.

The mathematical treatment of astronomy began with [[Isaac Newton|Newton]]'s development of [[celestial mechanics]] and the laws of [[gravitation]]. However, it was triggered by earlier work of astronomers such as [[Johannes Kepler|Kepler]]. By the 19th century, astronomy had developed into formal science, with the introduction of instruments such as the [[spectroscope]] and [[photography]], along with much-improved telescopes and the creation of professional observatories.

==Interdisciplinary studies==
{{unreferenced section|date=October 2019}}

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

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

A comparable discipline is [[oceanography]], as it draws upon a similar breadth of scientific disciplines. Oceanography is sub-categorized into more specialized cross-disciplines, such as [[physical oceanography]] and [[marine biology]]. As the [[marine ecosystem]] is vast and diverse, marine biology is further divided into many subfields, including specializations in particular [[species]].

There is also a subset of cross-disciplinary fields with strong currents that run counter to specialization by the nature of the problems they address. Put another way: In some fields of integrative application, specialists in more than one field are a key part of most scientific discourse. Such integrative fields, for example, include [[nanoscience]], [[astrobiology]], and [[complex system]] [[Informatics (academic field)|informatics]].

===Materials science===
{{Main|Materials science}}
[[File:Materials science tetrahedron;structure, processing, performance, and proprerties.svg|thumb|The materials paradigm represented as a tetrahedron]]
Materials science is a relatively new, interdisciplinary field that deals with the study of [[matter]] and its properties and the discovery and design of new materials. Originally developed through the field of [[metallurgy]], the study of the properties of materials and solids has now expanded into all materials. The field covers the chemistry, physics, and engineering applications of materials, including metals, ceramics, artificial polymers, and many others. The field's core deals with relating the structure of materials with their properties.

Materials science is at the forefront of research in science and engineering. It is an essential part of [[forensic engineering]] (the investigation of materials, products, structures, or components that fail or do not operate or function as intended, causing personal injury or damage to property) and [[failure analysis]], the latter being the key to understanding, for example, the cause of various aviation accidents. Many of the most pressing scientific problems that are faced today are due to the limitations of the materials that are available, and, as a result, breakthroughs in this field are likely to have a significant impact on the future of technology.

The basis of materials science involves studying the structure of materials and relating them to their [[property|properties]]. Understanding this structure-property correlation, material scientists can then go on to study the relative performance of a material in a particular application. The major determinants of the structure of a material and, thus, of its properties are its constituent chemical elements and how it has been processed into its final form. These characteristics, taken together and related through the laws of [[thermodynamics]] and [[kinetics (physics)|kinetics]], govern a material's [[microstructure]] and thus its properties.

==History==
{{See also|Natural philosophy|History of science}}

Some scholars trace the origins of natural science as far back as pre-literate human societies, where understanding the natural world was necessary for survival.{{sfn|Grant|2007|p=1}} People observed and built up knowledge about the behavior of animals and the usefulness of plants as food and medicine, which was passed down from generation to generation.{{sfn|Grant|2007|p=1}} These primitive understandings gave way to more formalized inquiry around 3500 to 3000 BC in the [[Mesopotamia]]n and [[Ancient Egypt]]ian cultures, which produced the first known written evidence of [[natural philosophy]], the precursor of natural science.{{sfn|Grant|2007|p=2}} While the writings show an interest in astronomy, mathematics, and other aspects of the physical world, the ultimate aim of inquiry about nature's workings was, in all cases, religious or mythological, not scientific.{{sfn|Grant|2007|pp=2–3}}

A tradition of scientific inquiry also emerged in [[Ancient China]], where [[Taoism|Taoist]] [[alchemy|alchemists]] and philosophers experimented with elixirs to [[life extension|extend life]] and cure ailments.{{sfn|Magner|2002|p=3}} They focused on the [[yin and yang]], or contrasting elements in nature; the yin was associated with femininity and coldness, while yang was associated with masculinity and warmth.{{sfn|Magner|2002|pp=3–4}} The five phases – fire, earth, metal, wood, and water – described a cycle of transformations in nature. The water turned into wood, which turned into the fire when it burned. The ashes left by fire were earth.{{sfn|Magner|2002|p=4}} Using these principles, Chinese philosophers and doctors explored human anatomy, characterizing organs as predominantly yin or yang, and understood the relationship between the pulse, the heart, and the flow of blood in the body centuries before it became accepted in the West.{{sfn|Magner|2002|p=5}}

Little evidence survives of how [[Ancient India]]n cultures around the [[Indus River]] understood nature, but some of their perspectives may be reflected in the [[Vedas]], a set of sacred [[Hinduism|Hindu]] texts.{{sfn|Magner|2002|p=5}} They reveal a conception of the universe as ever-expanding and constantly being recycled and reformed.{{sfn|Magner|2002|p=5}} Surgeons in the [[Ayurvedic]] tradition saw health and illness as a combination of three humors: [[wind]], [[bile]] and [[phlegm]].{{sfn|Magner|2002|p=5}} A healthy life resulted from a balance among these humors.{{sfn|Magner|2002|p=5}} In Ayurvedic thought, the body consisted of five elements: earth, water, fire, wind, and space.{{sfn|Magner|2002|p=5}} Ayurvedic surgeons performed complex surgeries and developed a detailed understanding of human anatomy.{{sfn|Magner|2002|p=5}}

[[Pre-Socratic philosophy|Pre-Socratic]] philosophers in [[Ancient Greece|Ancient Greek]] culture brought natural philosophy a step closer to direct inquiry about cause and effect in nature between 600 and 400 BC. However, an element of magic and mythology remained.{{sfn|Grant|2007|p=8}} Natural phenomena such as earthquakes and eclipses were explained increasingly in the context of nature itself instead of being attributed to angry gods.{{sfn|Grant|2007|p=8}} [[Thales|Thales of Miletus]], an early philosopher who lived from 625 to 546 BC, explained earthquakes by theorizing that the world floated on water and that water was the fundamental element in nature.{{sfn|Barr|2006|p=2}} In the 5th century BC, [[Leucippus]] was an early exponent of [[atomism]], the idea that the world is made up of fundamental indivisible particles.{{sfn|Barr|2006|p=3}} [[Pythagoras]] applied Greek innovations in mathematics to astronomy and suggested that the earth was [[sphere|spherical]].{{sfn|Barr|2006|p=3}}

===Aristotelian natural philosophy (400 BC–1100 AD)===
[[File: Aristotle's model of Inheritance.png|thumb|upright=1.3|left|Aristotle's view of inheritance, as a model of the transmission of patterns of movement of the body fluids from parents to child, and of [[Hylomorphism|Aristotelian form]] from the father]]
{{further|Aristotle's biology}}

Later [[Socrates|Socratic]] and [[Plato]]nic thought focused on ethics, morals, and art and did not attempt an investigation of the physical world; Plato criticized pre-Socratic thinkers as materialists and anti-religionists.{{sfn|Grant|2007|pp=21–22}} [[Aristotle]], however, a student of Plato who lived from 384 to 322 BC, paid closer attention to the natural world in his philosophy.{{sfn|Grant|2007|pp=27–28}} In his ''[[History of Animals]]'', he described the inner workings of 110 species, including the [[stingray]], [[catfish]] and [[bee]].{{sfn|Grant|2007|pp=33–34}} He investigated chick embryos by breaking open eggs and observing them at various stages of development.{{sfn|Grant|2007|p=34}} Aristotle's works were influential through the 16th century, and he is considered to be the [[Aristotle's biology|father of biology for his pioneering work in that science]].{{sfn|Grant|2007|pp=34–35}} He also presented philosophies about physics, nature, and astronomy using [[inductive reasoning]] in his works ''[[Physics (Aristotle)|Physics]]'' and ''[[Meteorology (Aristotle)|Meteorology]]''.{{sfn|Grant|2007|pp=37–39, 53}}

[[File:Sanzio 01 Plato Aristotle.jpg|thumb|upright|Plato (left) and Aristotle in [[The School of Athens|a 1509 painting]] by [[Raphael]]. Plato rejected inquiry into natural philosophy as against religion, while his student, Aristotle, created a body of work on the natural world that influenced generations of scholars.]]

While Aristotle considered natural philosophy more seriously than his predecessors, he approached it as a theoretical branch of science.{{sfn|Grant|2007|p=52}} Still, inspired by his work, [[Ancient Rome|Ancient Roman]] philosophers of the early 1st century AD, including [[Lucretius]], [[Seneca the Younger|Seneca]] and [[Pliny the Elder]], wrote treatises that dealt with the rules of the natural world in varying degrees of depth.{{sfn|Grant|2007|p=95}} Many [[Ancient Rome|Ancient Roman]] [[Neoplatonism|Neoplatonists]] of the 3rd to the 6th centuries also adapted Aristotle's teachings on the physical world to a philosophy that emphasized spiritualism.{{sfn|Grant|2007|pp=54, 59}} Early [[medieval]] philosophers including [[Macrobius]], [[Calcidius]] and [[Martianus Capella]] also examined the physical world, largely from a cosmological and [[cosmography|cosmographical]] perspective, putting forth theories on the arrangement of celestial bodies and the heavens, which were posited as being composed of [[aether (classical element)|aether]].{{sfn|Grant|2007|p=103}}

Aristotle's works on natural philosophy continued to be translated and studied amid the rise of the [[Byzantine Empire]] and [[Abbasid Caliphate]].{{sfn|Grant|2007|pp=61–66}}

In the Byzantine Empire, [[John Philoponus]], an Alexandrian Aristotelian commentator and Christian theologian, was the first to question Aristotle's physics teaching. Unlike Aristotle, who based his physics on verbal argument, Philoponus instead relied on observation and argued for observation rather than resorting to a verbal argument.<ref>{{cite web|url=http://homepages.wmich.edu/~mcgrew/philfall.htm|title=John Philoponus, Commentary on Aristotle's Physics, pp|website=homepages.wmich.edu|access-date=2018-04-25|archive-url=https://web.archive.org/web/20160111105753/http://homepages.wmich.edu/~mcgrew/philfall.htm|archive-date=2016-01-11}}</ref> He introduced the [[theory of impetus]]. John Philoponus' criticism of Aristotelian principles of physics served as inspiration for Galileo Galilei during the [[Scientific Revolution]].<ref>{{cite book|url=https://plato.stanford.edu/archives/spr2016/entries/philoponus/|title=The Stanford Encyclopedia of Philosophy|first=Christian|last=Wildberg|editor-first=Edward N.|editor-last=Zalta|date=8 March 2018|publisher=Metaphysics Research Lab, Stanford University|via=Stanford Encyclopedia of Philosophy|access-date=9 May 2023|archive-date=22 August 2019|archive-url=https://web.archive.org/web/20190822110331/https://plato.stanford.edu/archives/spr2016/entries/philoponus/|url-status=live}}</ref><ref>Lindberg, David. (1992) ''The Beginnings of Western Science''. University of Chicago Press. Page 162.</ref>

A revival in mathematics and science took place during the time of the [[Abbasid Caliphate]] from the 9th century onward, when Muslim scholars expanded upon Greek and [[India]]n natural philosophy.{{sfn|Barr|2006|p=11}} The words ''[[Alcohol (disambiguation)|alcohol]]'', ''[[algebra]]'' and ''[[zenith]]'' all have [[Arabic]] roots.{{sfn|Barr|2006|pp=11–12}}

===Medieval natural philosophy (1100–1600)===
{{see also|Renaissance of the 12th century}}
Aristotle's works and other Greek natural philosophy did not reach the West until about the middle of the 12th century, when works were translated from [[Greek people|Greek]] and Arabic into [[Latin]].{{sfn|Grant|2007|pp=95, 130}} The development of European civilization later in the Middle Ages brought with it further advances in natural philosophy.{{sfn|Grant|2007|p=106}} European inventions such as the [[horseshoe]], [[horse collar]] and [[crop rotation]] allowed for rapid population growth, eventually giving way to urbanization and the foundation of schools connected to monasteries and cathedrals in modern-day [[France]] and [[England]].{{sfn|Grant|2007|pp=106–107}} Aided by the schools, an approach to Christian [[theology]] developed that sought to answer questions about nature and other subjects using logic.{{sfn|Grant|2007|p=115}} This approach, however, was seen by some detractors as [[heresy]].{{sfn|Grant|2007|p=115}} 

By the 12th century, Western European scholars and philosophers came into contact with a body of knowledge of which they had previously been ignorant: a large corpus of works in Greek and Arabic that were preserved by Islamic scholars.{{sfn|Grant|2007|p=130}} Through translation into Latin, Western Europe was introduced to Aristotle and his natural philosophy.{{sfn|Grant|2007|p=130}} These works were taught at new universities in [[Paris]] and [[Oxford]] by the early 13th century, although the practice was frowned upon by the Catholic church.{{sfn|Grant|2007|p=143}} A 1210 decree from the [[Synod]] of Paris ordered that "no lectures are to be held in Paris either publicly or privately using Aristotle's books on natural philosophy or the commentaries, and we forbid all this under pain of ex-communication."{{sfn|Grant|2007|p=143}}

In the late Middle Ages, [[Spain|Spanish]] philosopher [[Dominicus Gundissalinus]] translated a treatise by the earlier Persian scholar [[Al-Farabi]] called ''On the Sciences'' into Latin, calling the study of the mechanics of nature ''Scientia naturalis'', or natural science.{{sfn|Grant|2007|p=155}} Gundissalinus also proposed his classification of the natural sciences in his 1150 work ''On the Division of Philosophy''.{{sfn|Grant|2007|p=155}} This was the first detailed classification of the sciences based on Greek and Arab philosophy to reach Western Europe.{{sfn|Grant|2007|p=155}} Gundissalinus defined natural science as "the science considering only things unabstracted and with motion," as opposed to mathematics and sciences that rely on mathematics.{{sfn|Grant|2007|p=156}} Following Al-Farabi, he separated the sciences into eight parts, including: physics, cosmology, meteorology, minerals science, and plant and animal science.{{sfn|Grant|2007|p=156}}

Later, philosophers made their own classifications of the natural sciences. [[Robert Kilwardby]] wrote ''On the Order of the Sciences'' in the 13th century that classed medicine as a mechanical science, along with agriculture, hunting, and theater, while defining natural science as the science that deals with bodies in motion.{{sfn|Grant|2007|pp=156–157}} [[Roger Bacon]], an English friar and philosopher, wrote that natural science dealt with "a principle of motion and rest, as in the parts of the elements of fire, air, earth, and water, and in all inanimate things made from them."{{sfn|Grant|2007|p=158}} These sciences also covered plants, animals and celestial bodies.{{sfn|Grant|2007|p=158}} 

Later in the 13th century, a Catholic priest and theologian [[Thomas Aquinas]] defined natural science as dealing with "mobile beings" and "things which depend on a matter not only for their existence but also for their definition."{{sfn|Grant|2007|pp=159–163}} There was broad agreement among scholars in medieval times that natural science was about bodies in motion. However, there was division about including fields such as medicine, music, and perspective.{{sfn|Grant|2007|p=234}} Philosophers pondered questions including the existence of a vacuum, whether motion could produce heat, the colors of rainbows, the motion of the earth, whether elemental chemicals exist, and where in the atmosphere rain is formed.{{sfn|Grant|2007|pp=236–237}}

In the centuries up through the end of the Middle Ages, natural science was often mingled with philosophies about magic and the occult.{{sfn|Grant|2007|pp=170–178}} Natural philosophy appeared in various forms, from treatises to encyclopedias to commentaries on Aristotle.{{sfn|Grant|2007|pp=189–190}} The interaction between natural philosophy and [[Christianity]] was complex during this period; some early theologians, including [[Tatian]] and [[Eusebius]], considered natural philosophy an outcropping of pagan Greek science and were suspicious of it.{{sfn|Grant|2007|pp=239–240}} Although some later Christian philosophers, including Aquinas, came to see natural science as a means of interpreting scripture, this suspicion persisted until the 12th and 13th centuries.{{sfn|Grant|2007|pp=241–243}} The [[Condemnations of 1210–1277|Condemnation of 1277]], which forbade setting philosophy on a level equal with theology and the debate of religious constructs in a scientific context, showed the persistence with which Catholic leaders resisted the development of natural philosophy even from a theological perspective.{{sfn|Grant|2007|pp=246–247}} Aquinas and [[Albertus Magnus]], another Catholic theologian of the era, sought to distance theology from science in their works.{{sfn|Grant|2007|p=251}} "I don't see what one's interpretation of Aristotle has to do with the teaching of the faith," he wrote in 1271.{{sfn|Grant|2007|p=252}}

===Newton and the Scientific Revolution (1600–1800)===
By the 16th and 17th centuries, natural philosophy evolved beyond commentary on Aristotle as more early Greek philosophy was uncovered and translated.{{sfn|Grant|2007|p=274}} The invention of the printing press in the 15th century, the invention of the microscope and telescope, and the [[Protestant Reformation]] fundamentally altered the social context in which scientific inquiry evolved in the West.{{sfn|Grant|2007|p=274}} [[Christopher Columbus]]'s discovery of a new world changed perceptions about the physical makeup of the world, while observations by [[Copernicus]], [[Tyco Brahe]] and [[Galileo]] brought a more accurate picture of the solar system as [[heliocentric]] and proved many of Aristotle's theories about the heavenly bodies false.{{sfn|Grant|2007|p=274–275}} Several 17th-century philosophers, including [[René Descartes]], [[Pierre Gassendi]], [[Marin Mersenne]], [[Nicolas Malebranche]], [[Thomas Hobbes]], [[John Locke]] and [[Francis Bacon]], made a break from the past by rejecting Aristotle and his medieval followers outright, calling their approach to natural philosophy superficial.{{sfn|Grant|2007|pp=276–277}}

[[File:JKepler.jpg|thumb|left|[[Johannes Kepler]] (1571–1630). Kepler's [[Astronomia Nova]] is "the first published account wherein a scientist documents how he has coped with the multitude of imperfect data to forge a theory of surpassing accuracy", therefore laying the groundwork for the scientific method.<ref>{{cite web | url=https://www.nasa.gov/kepler/education/johannes | title=Johannes Kepler: His Life, His Laws and Times | date=24 September 2016 | access-date=1 September 2023 | archive-date=24 June 2021 | archive-url=https://web.archive.org/web/20210624003856/https://www.nasa.gov/kepler/education/johannes/ }}</ref>]]
The titles of Galileo's work ''Two New Sciences'' and [[Johannes Kepler]]'s ''New Astronomy'' underscored the atmosphere of change that took hold in the 17th century as Aristotle was dismissed in favor of novel methods of inquiry into the natural world.{{sfn|Grant|2007|p=278}} Bacon was instrumental in popularizing this change; he argued that people should use the [[arts]] and sciences to gain dominion over nature.{{sfn|Grant|2007|pp=278–279}} To achieve this, he wrote that "human life [must] be endowed with discoveries and powers."{{sfn|Grant|2007|p=279}} He defined natural philosophy as "the knowledge of Causes and secret motions of things; and enlarging the bounds of Human Empire, to the effecting of all things possible."{{sfn|Grant|2007|p=278}} Bacon proposed that scientific inquiry be supported by the state and fed by the collaborative research of scientists, a vision that was unprecedented in its scope, ambition, and forms at the time.{{sfn|Grant|2007|p=279}} 

Natural philosophers came to view nature increasingly as a mechanism that could be taken apart and understood, much like a complex clock.{{sfn|Grant|2007|pp=280–285}} Natural philosophers including [[Isaac Newton]], [[Evangelista Torricelli]] and [[Francesco Redi]], [[Edme Mariotte]], [[Jean-Baptiste Denis]] and [[Jacques Rohault]] conducted experiments focusing on the flow of water, measuring [[atmospheric pressure]] using a [[barometer]] and disproving [[spontaneous generation]].{{sfn|Grant|2007|pp=280–290}} Scientific societies and scientific journals emerged and were spread widely through the printing press, touching off the [[Scientific Revolution]].{{sfn|Grant|2007|pp=280–295}} Newton in 1687 published his ''The Mathematical Principles of Natural Philosophy'', or ''Principia Mathematica'', which set the groundwork for physical laws that remained current until the 19th century.{{sfn|Grant|2007|pp=304–306}}

Some modern scholars, including Andrew Cunningham, Perry Williams, and [[Floris Cohen]], argue that natural philosophy is not properly called science and that genuine scientific inquiry began only with the scientific revolution.{{sfn|Grant|2007|p=307}} According to Cohen, "the emancipation of science from an overarching entity called 'natural philosophy is one defining characteristic of the Scientific Revolution."{{sfn|Grant|2007|p=307}} Other historians of science, including [[Edward Grant]], contend that the scientific revolution that blossomed in the 17th, 18th, and 19th centuries occurred when principles learned in the exact sciences of optics, mechanics, and astronomy began to be applied to questions raised by natural philosophy.{{sfn|Grant|2007|p=307}} Grant argues that Newton attempted to expose the mathematical basis of nature – the immutable rules it obeyed – and, in doing so, joined natural philosophy and mathematics for the first time, producing an early work of modern physics.{{sfn|Grant|2007|pp=317–318}}

[[File: Portrait of Sir Isaac Newton, 1689.jpg|thumb|upright|[[Isaac Newton]] is widely regarded as one of the most influential scientists of all time.]]
The Scientific Revolution, which began to take hold in the 17th century, represented a sharp break from Aristotelian modes of inquiry.{{sfn|Barr|2006|p=26}} One of its principal advances was the use of the [[scientific method]] to investigate nature. Data was collected, and [[repeatability|repeatable]] measurements were made in [[experiment]]s.{{sfn|Barr|2006|pp=26–27}} Scientists then formed [[hypothesis|hypotheses]] to explain the results of these experiments.{{sfn|Barr|2006|p=27}} The hypothesis was then tested using the principle of [[falsifiability]] to prove or disprove its accuracy.{{sfn|Barr|2006|p=27}} The natural sciences continued to be called natural philosophy, but the adoption of the scientific method took science beyond the realm of philosophical conjecture and introduced a more structured way of examining nature.{{sfn|Barr|2006|p=26}}

Newton, an English mathematician and physicist, was a seminal figure in the Scientific Revolution.{{sfn|Barr|2006|p=33}} Drawing on advances made in astronomy by Copernicus, Brahe, and Kepler, Newton derived the [[Newton's law of universal gravitation|universal law of gravitation]] and [[Newton's laws of motion|laws of motion]].{{sfn|Barr|2006|pp=33–35}} These laws applied both on Earth and in outer space, uniting two spheres of the physical world previously thought to function independently, according to separate physical rules.{{sfn|Barr|2006|p=35}} Newton, for example, showed that the [[tide]]s were caused by the gravitational pull of the [[Moon]].{{sfn|Barr|2006|p=36}} Another of Newton's advances was to make mathematics a powerful explanatory tool for natural phenomena.{{sfn|Barr|2006|p=37}} While natural philosophers had long used mathematics as a means of measurement and analysis, its principles were not used as a means of understanding cause and effect in nature until Newton.{{sfn|Barr|2006|p=37}}

In the 18th century and 19th century, scientists including [[Charles-Augustin de Coulomb]], [[Alessandro Volta]], and [[Michael Faraday]] built upon Newtonian mechanics by exploring [[electromagnetism]], or the interplay of forces with positive and negative charges on [[electric charge|electrically charged]] particles.{{sfn|Barr|2006|p=48}} Faraday proposed that forces in nature operated in "[[Field (physics)|fields]]" that filled space.{{sfn|Barr|2006|p=49}} The idea of fields contrasted with the Newtonian construct of gravitation as simply "action at a distance", or the attraction of objects with nothing in the space between them to intervene.{{sfn|Barr|2006|p=49}} [[James Clerk Maxwell]] in the 19th century unified these discoveries in a coherent [[Maxwell's equations|theory of electrodynamics]].{{sfn|Barr|2006|p=48}} Using mathematical equations and experimentation, Maxwell discovered that space was filled with charged particles that could act upon each other and were a medium for transmitting charged waves.{{sfn|Barr|2006|p=48}}

Significant advances in chemistry also took place during the Scientific Revolution. [[Antoine Lavoisier]], a French chemist, refuted the [[phlogiston theory]], which posited that things burned by releasing "phlogiston" into the air.{{sfn|Barr|2006|p=49}} [[Joseph Priestley]] had discovered [[oxygen]] in the 18th century, but Lavoisier discovered that [[combustion]] was the result of [[oxidation]].{{sfn|Barr|2006|p=49}} He also constructed a table of 33 elements and invented modern chemical nomenclature.{{sfn|Barr|2006|p=49}} Formal biological science remained in its infancy in the 18th century, when the focus lay upon the [[Scientific classification|classification and categorization]] of natural life. This growth in [[natural history]] was led by [[Carl Linnaeus]], whose 1735 [[Taxonomy (biology)|taxonomy]] of the natural world is still in use. Linnaeus, in the 1750s, introduced [[Binomial nomenclature|scientific names]] for all his species.{{sfn|Mayr|1982|pp=171–179}}

===19th-century developments (1800–1900)===
[[File: Michelson-Morley experiment (en).svg|thumb|The [[Michelson–Morley experiment]] was used to disprove that light propagated through a [[luminiferous aether]]. This 19th-century concept was then superseded by [[Albert Einstein]]'s [[special theory of relativity]].]]

By the 19th century, the study of science had come into the purview of professionals and institutions. In so doing, it gradually acquired the more modern name of ''natural science.'' The term ''scientist'' was coined by [[William Whewell]] in an 1834 review of [[Mary Somerville]]'s ''On the Connexion of the Sciences''.<ref name=Holmes>{{cite book |last1= Holmes|first1= R|title= The age of wonder: How the romantic generation discovered the beauty and terror of science|date= 2008|publisher= Harper Press|location= London|isbn= 978-0-00-714953-7|page= 449}}</ref> But the word did not enter general use until nearly the end of the same century.<ref>{{Cite journal|last=Ross|first=Sydney|date=1962|title=Scientist: The story of a word|url=https://www.tandfonline.com/doi/abs/10.1080/00033796200202722|journal=Annals of Science|volume=18|issue=2|pages=65–85|doi=10.1080/00033796200202722|issn=0003-3790}}</ref><ref>{{Cite journal|date=2024-10-28|title='Review of On The Connexion of the Physical Sciences by Mrs Somerville' (1834)|url=https://www.taylorfrancis.com/chapters/edit/10.4324/9781003548249-15/review-connexion-physical-sciences-mrs-somerville-1834-william-whewell|journal=Taylor & Francis|language=en|doi=10.4324/9781003548249-15/review-connexion-physical-sciences-mrs-somerville-1834-william-whewell}}</ref>

===Modern natural science (1900–present)===
According to a famous 1923 textbook, ''Thermodynamics and the Free Energy of Chemical Substances'', by the American chemist [[Gilbert N. Lewis]] and the American physical chemist [[Merle Randall]],<ref>{{cite book|title=Thermodynamics and the Free Energy of Chemical Substances |url=https://archive.org/details/thermodynamicsfr00gnle_603 |first1=Gilbert N. |last1=Lewis |first2=Merle |last2=Randall |publisher=McGraw-Hill Book Company |edition=First |others=later Printing edition |date=1923 |asin= B000GSLHZS}}</ref> the natural sciences contain three great branches:

<blockquote>Aside from the logical and mathematical sciences, there are three great branches of ''natural science'' which stand apart by reason of the variety of far reaching deductions drawn from a small number of primary postulates — they are [[mechanics]], [[electrodynamics]], and [[thermodynamics]].<ref>{{cite book|last=Huggins|first=Robert A.|title=Energy storage|url=https://archive.org/details/energystorage00hugg|url-access=limited|date=2010|publisher=Springer|location=New York|isbn=978-1-4419-1023-3|edition=Online-Ausg. |page=[https://archive.org/details/energystorage00hugg/page/n41 13]}}</ref></blockquote>

Today, natural sciences are more commonly divided into life sciences, such as botany and zoology, and physical sciences, which include physics, chemistry, astronomy, and Earth sciences.

==See also==
* [[Branches of science]]
* [[Empiricism]]
* [[List of academic disciplines and sub-disciplines]]
* [[Natural history]]
* [[Natural Sciences (Cambridge)]], for the [[Tripos]] at the University of Cambridge

==References==
{{Reflist}}

===Bibliography===
{{refbegin}}
* {{cite book |last=Barr |first=Stephen M. |date=2006 |title=A Students Guide to Natural Science |publisher=[[Intercollegiate Studies Institute]] |location=Wilmington, DE |isbn=978-1-932236-92-7 |url=https://archive.org/details/guidetoscience00mann }}
* {{cite book |last=Grant |first=Edward |date=2007 |title=A History of Natural Philosophy: From the Ancient World to the 19th century |publisher=[[Cambridge University Press]] |location=Cambridge |isbn=978-0-521-68957-1}}
* {{cite book |last=Lagemaat |first=Richard van de |date=2006 |title=Theory of Knowledge for the IB Diploma |publisher=Cambridge University Press |location=Cambridge |isbn=978-0-521-54298-2 |url=https://books.google.com/books?id=l_HMz6Ub-rcC&q=hard+science+physics+chemistry&pg=PA283 |access-date=2020-11-10 |archive-date=2023-12-13 |archive-url=https://web.archive.org/web/20231213102803/https://books.google.com/books?id=l_HMz6Ub-rcC&q=hard+science+physics+chemistry&pg=PA283#v=snippet&q=hard%20science%20physics%20chemistry&f=false |url-status=live }}
* {{cite journal |title=Defining Natural Sciences |journal=Behaviorology Today |date=2002 |first=Stephen F. |last=Ledoux |volume=5 |issue=1 |page=34 |url=http://behaviorology.org/pdf/DefineNatlSciences.pdf |quote=Fundamentally, natural sciences are defined as disciplines that deal only with natural events (i.e., independent and dependent variables in nature) using scientific methods. |publisher=[[Marcel Dekker, Inc.]] |location=New York |isbn=978-0-8247-0824-5 |ref={{sfnRef|Magner|2002}} |archive-url=https://web.archive.org/web/20120325192047/http://www.behaviorology.org/pdf/DefineNatlSciences.pdf |archive-date=2012-03-25 }}
* {{cite book |last=Mayr |first=Ernst |date=1982 |title=The Growth of Biological Thought: Diversity, Evolution, and Inheritance |publisher=[[The Belknap Press of Harvard University Press]] |location=Cambridge, Massachusetts |isbn=978-0-674-36445-5 |url=https://archive.org/details/growthofbiologic00mayr }}
* {{cite book |last=Oglivie |first=Brian W. |date=2008 |title=The Science of Describing: Natural History in Renaissance Europe |publisher=[[University of Chicago Press]] |location=Chicago |isbn=978-0-226-62088-6}}
{{refend}}

==Further reading==
* [https://web.archive.org/web/20110515162441/http://www.behaviorology.org/pdf/DefineNatlSciences.pdf Defining Natural Sciences] Ledoux, S. F., 2002: Defining Natural Sciences, ''Behaviorology Today'', '''5(1)''', 34–36.
* {{cite book|last=Stokes|first=Donald E.|title=Pasteur's Quadrant: Basic Science and Technological Innovation|url=https://archive.org/details/pasteursquadrant00stok|url-access=registration|date=1997|publisher=[[Brookings Institution Press]]|location=Washington, D.C.|isbn=978-0-8157-8177-6|others=Revised and translated by Albert V. Carozzi and Marguerite Carozzi<!--|ref={{sfnRef|Gohau|1990}}-->}}
{{Wiktionary}}
* [http://hrst.mit.edu/ The History of Recent Science and Technology]
* [https://web.archive.org/web/20111129180040/http://sciencia.com/ Natural Sciences] Contains updated information on research in the Natural Sciences including biology, geography and the applied life and earth sciences.
* [https://web.archive.org/web/20031214051100/http://scibooks.org/ Reviews of Books About Natural Science] This site contains over 50 previously published reviews of books about natural science, plus selected essays on timely topics in natural science.
* [https://web.archive.org/web/20101106080019/http://search.engrant.com/ Scientific Grant Awards Database] Contains details of over 2,000,000 scientific research projects conducted over the past 25 years.
* [https://web.archive.org/web/20170922042747/http://esciencenews.com/sources E!Science] Up-to-date science news aggregator from major sources including universities.
{{Natural science}}
{{History of science}}
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