Also
03-31-2014, 06:44 AM
Any physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it. No matter how many times the results of experiments agree with some theory, you can never be sure that the next time the result will not contradict the theory. On the other hand, you can disprove a theory by finding even a single observation that disagrees with the predictions of the theory... Each time new experiments are observed to agree with the predictions the theory survives, and our confidence in it is increased; but if ever a new observation is found to disagree, we have to abandon or modify the theory.
- A BRIEF HISTORY OF TIME, Stephen Hawking
No amount of experimentation can ever prove me right; a single experiment can prove me wrong.
- Albert Einstein
Induction is the glory of science and the scandal of philosophy
- Charles Broad
i. There have been many empirically successful theories in the history of science which have subsequently been rejected and whose theoretical terms do not refer according to our best current theories.
ii. Our best current theories are no different in kind from those discarded theories and so we have no reason to think they will not ultimately be replaced as well.
- Larry Laudan
... in science there is no 'knowledge', in the sense in which Plato and Aristotle understood the word, in the sense which implies finality; in science, we never have sufficient reason for the belief that we have attained the truth. ... This view means, furthermore, that we have no proofs in science (excepting, of course, pure mathematics and logic). In the empirical sciences, which alone can furnish us with information about the world we live in, proofs do not occur, if we mean by 'proof' an argument which establishes once and for ever the truth of a theory.
Sir Karl Popper, The Problem of Induction, 1953
If you thought that science was certain — well, that is just an error on your part.
Richard Feynman (1918-1988).
A superseded, or obsolete, scientific theory is a scientific theory that mainstream scientific consensus once commonly accepted but now no longer considers the most complete description of reality, or simply false. This label does not cover protoscientific or fringe science theories with limited support in the scientific community. Also, it does not mean theories that were never widely accepted. Some theories that were only supported under specific political authorities, such as Lysenkoism, may also be described as obsolete or superseded.
In some cases a theory or idea is found baseless and is simply discarded. For example, the phlogiston theory was entirely replaced by the quite different concept of energy and related laws. In other cases an existing theory is replaced by a new theory that retains significant elements of the earlier theory; in these cases, the older theory is often still useful for many purposes, and may be more easily understood than the complete theory and lead to simpler calculations. An example of this is the use of Newtonian physics, which differs from the currently accepted relativistic physics by a factor that is negligibly small at velocities much lower than that of light. All of Newtonian physics is so satisfactory for most purposes that it is more widely used except at velocities that are a significant fraction of the speed of light, and simpler Newtonian but not relativistic mechanics is usually taught in schools. Another case is the theory that the earth is approximately flat; while it has for centuries been known to be wrong for long distances, considering part of the earth's surface as flat is usually sufficient for many maps covering areas that are not extremely large, and surveying.
http://upload.wikimedia.org/wikipedia/commons/thumb/d/d4/Cellarius_ptolemaic_system_c2.jpg/287px-Cellarius_ptolemaic_system_c2.jpg
The obsolete Geocentric model of the universe places the Earth at the centre.
Superseded theories
Biology
Spontaneous generation - is a principle regarding the origin of life from inanimate matter, which held that this process was a commonplace and everyday occurrence, as distinguished from univocal generation, or reproduction from parent(s). Falsified by an elegant experiment by Louis Pasteur—where apparently spontaneous generation of microorganisms occurred, it did not happen on repeating the process without access to unfiltered air; on then opening the apparatus to the atmosphere, bacterial growth started.
Transmutation of species, Lamarckism, inheritance of acquired characteristics - first theories of evolution. Not supported by experiment, and rendered obsolete by Darwinian evolution, Mendelian genetics and epigenetics (although some elements of Lamarckian evolution are coming back in the area of epigenetics).
Mendelian genetics, classical genetics, Boveri–Sutton chromosome theory - first genetical theories. Not invalidated as such, but subsumed into molecular genetics.
Maternal impression – the theory that the mother's thoughts created birth defects. No experimental support (a notion rather than a theory), and rendered obsolete by genetic theory (see also fetal origins of adult disease, genomic imprinting)
Miasma theory of disease – the theory that diseases are caused by "bad air". No experimental support, and rendered obsolete by the germ theory of disease.
Preformationism – the theory that all organisms have existed since the beginning of life, and that gametes contain a miniature but complete preformed individual. No support when microscopy became available. Rendered obsolete by cytology, discovery of DNA, and atomic theory.
Recapitulation theory – the theory that "ontogeny recapitulates phylogeny". See Baer's laws of embryology.
Telegony – the theory that an offspring can inherit characteristics from a previous mate of its mother's as well as its actual parents, often associated with racism.
Vitalism – the theory that living things are alive because of some "vital force" independent of nonliving matter, as opposed to because of some appropriate assembly of nonliving matter. It was gradually discredited by the rise of organic chemistry, biochemistry, and molecular biology, fields that failed to discover any "vital force". Friedrich Wöhler's synthesis of urea from ammonium cyanate was only one step in a long road, not a great refutation.
Out of Asia theory of human origin – The majority view is of a recent African origin of modern humans, although a multiregional origin of modern humans hypothesis has much support (which incorporates past evidence of Asian origins)
Chemistry
Caloric theory - the theory that a self-repelling fluid called "caloric" was the substance of heat. Rendered obsolete by the mechanical theory of heat.
Classical elements - All matter was once thought to be composed of various combinations of classical elements (most famously air, earth, fire, and water). This was finally refuted by Antoine Lavoisier's publication of Elements of Chemistry, which contained the first modern list of chemical elements, in 1789.
Phlogiston theory – replaced by Lavoisier's work on oxidation
Points two and three of Dalton's Atomic Theory
Vitalism - See section on biology.
Physics
Emission theory of vision – discredited by Ibn al-Haytham (Alhacen)
Aristotelian physics – superseded by Newtonian physics
Ptolemy's law of refraction, replaced by Snell's law
Luminiferous aether – failed to be detected by the sufficiently sensitive Michelson-Morley experiment, made obsolete by Einstein's work.
Caloric theory – Lavoisier's successor to phlogiston, discredited by Rumford's and Joule's work
Vis viva – Gottfried Leibniz's elementary and limited early formulation of the principle of conservation of energy
"Purely electrostatic" theories of the generation of voltage differences.
Emitter theory – another now-obsolete theory of light propagation.
Progression of atomic theory
Democritus, the originator of atomic theory, held that everything is composed of atoms, which are indestructible
John Dalton's model of the atom, which held that atoms are indivisible and indestructible (superseded by nuclear physics) and that all atoms of a given element are identical in mass (superseded by discovery of atomic isotopes).
Plum pudding model of the atom—assuming the protons and electrons were mixed together in a single mass
Rutherford model of the atom with an impenetrable nucleus orbited by electrons
Bohr model with quantized orbits
Electron cloud model following the development of quantum mechanics in 1925 and the eventual atomic orbital models derived from the quantum mechanical solution to the hydrogen atom
All of classical physics, including Newtonian physics, superseded by relativistic physics and quantum physics. However, classical physics is a limiting case of the latter two theories, and it is often a very good approximation.
Astronomy and cosmology
Ptolemaic system – replaced by Nicolaus Copernicus' Heliocentric model.
Geocentric universe – made obsolete by Copernicus
Heliocentric universe – made obsolete by discovery of the structure of the Milky Way. Heliocentrism only applies to the Solar System, and only approximately, since the Sun's center is not at the Solar System's center of mass.
Copernican system – made obsolete by Johannes Kepler and Isaac Newton
Newtonian gravity – superseded by general relativity, to which it is an excellent approximation unless typical speeds approach that of light in a vacuum (c). The anomalous perihelion precession of Mercury was the first observational evidence that Newtonian gravity was not totally accurate.
Luminiferous aether theory
Steady State Theory, a model developed by Hermann Bondi, Thomas Gold, and Fred Hoyle whereby the expanding universe was in a steady state, and had no beginning. It was a competitor of the Big Bang model until evidence supporting the Big Bang and falsifying the steady state was found.
Geography and climate
Flat Earth theory. On length scales much smaller than the radius of the Earth, a flat map projection gives a quite accurate and practically useful approximation to true distances and sizes, but departures from flatness become increasingly significant over larger distances.
Terra Australis
Hollow Earth theory
The Open Polar Sea, an ice-free sea once supposed to surround the North Pole
Rain follows the plow – the theory that human settlement increases rainfall in arid regions (only true to the extent that crop fields evapotranspirate more than barren wilderness)
Geology
The following were superseded by Plate tectonics:
Expanding Earth theory (superseded by subduction)
Geosyncline theory
The theory of continental drift was incorporated into and improved upon by plate tectonics
Catastrophism was largely replaced by uniformitarianism
Neptunism replaced by Plutonism
Psychology
Pure behaviorist explanations for language acquisition in infancy, falsified by the study of cognitive adaptations for language.
Medicine
Theory of the four bodily humours (see also Four temperaments)
Eclectic Medicine – Transformed into alternative medicine, and is no longer considered a scientific theory.
Physiognomy, related to phrenology, held that inner character was strongly correlated with physical appearance.
Obsolete branches of enquiry
Alchemy, which led to the development of chemistry
Astrology, which led to the development of astronomy
Phrenology, a pseudoscience
Numerology, a pseudoscience
Theories now considered incomplete
Here are theories that are no longer considered the most complete representation of reality, but are still useful in particular domains or under certain conditions. For some theories a more complete model is known, but in practical use the coarser approximation provides good results with much less calculation.
Atomic nuclei disintegrate at high energy.
Newtonian mechanics was extended by the theory of relativity and by quantum mechanics. Relativistic corrections to Newtonian mechanics are unmeasurably small at velocities not approaching the speed of light, and quantum corrections are usually negligible at atomic or larger scales; Newtonian mechanics is totally satisfactory in engineering and physics under most circumstances.
Classical electrodynamics is a very close approximation to quantum electrodynamics except at very small scales and low field strengths.
Bohr model of the atom was extended by the quantum mechanical model of the atom.
The formula known as Newton's sine-square law of air resistance for the force of a fluid on a body, though not actually formulated by Newton but by others using a method of calculation used by Newton, has been found incorrect and not useful except for high-speed hypersonic flow.
http://en.wikipedia.org/wiki/Superseded_scientific_theories
- A BRIEF HISTORY OF TIME, Stephen Hawking
No amount of experimentation can ever prove me right; a single experiment can prove me wrong.
- Albert Einstein
Induction is the glory of science and the scandal of philosophy
- Charles Broad
i. There have been many empirically successful theories in the history of science which have subsequently been rejected and whose theoretical terms do not refer according to our best current theories.
ii. Our best current theories are no different in kind from those discarded theories and so we have no reason to think they will not ultimately be replaced as well.
- Larry Laudan
... in science there is no 'knowledge', in the sense in which Plato and Aristotle understood the word, in the sense which implies finality; in science, we never have sufficient reason for the belief that we have attained the truth. ... This view means, furthermore, that we have no proofs in science (excepting, of course, pure mathematics and logic). In the empirical sciences, which alone can furnish us with information about the world we live in, proofs do not occur, if we mean by 'proof' an argument which establishes once and for ever the truth of a theory.
Sir Karl Popper, The Problem of Induction, 1953
If you thought that science was certain — well, that is just an error on your part.
Richard Feynman (1918-1988).
A superseded, or obsolete, scientific theory is a scientific theory that mainstream scientific consensus once commonly accepted but now no longer considers the most complete description of reality, or simply false. This label does not cover protoscientific or fringe science theories with limited support in the scientific community. Also, it does not mean theories that were never widely accepted. Some theories that were only supported under specific political authorities, such as Lysenkoism, may also be described as obsolete or superseded.
In some cases a theory or idea is found baseless and is simply discarded. For example, the phlogiston theory was entirely replaced by the quite different concept of energy and related laws. In other cases an existing theory is replaced by a new theory that retains significant elements of the earlier theory; in these cases, the older theory is often still useful for many purposes, and may be more easily understood than the complete theory and lead to simpler calculations. An example of this is the use of Newtonian physics, which differs from the currently accepted relativistic physics by a factor that is negligibly small at velocities much lower than that of light. All of Newtonian physics is so satisfactory for most purposes that it is more widely used except at velocities that are a significant fraction of the speed of light, and simpler Newtonian but not relativistic mechanics is usually taught in schools. Another case is the theory that the earth is approximately flat; while it has for centuries been known to be wrong for long distances, considering part of the earth's surface as flat is usually sufficient for many maps covering areas that are not extremely large, and surveying.
http://upload.wikimedia.org/wikipedia/commons/thumb/d/d4/Cellarius_ptolemaic_system_c2.jpg/287px-Cellarius_ptolemaic_system_c2.jpg
The obsolete Geocentric model of the universe places the Earth at the centre.
Superseded theories
Biology
Spontaneous generation - is a principle regarding the origin of life from inanimate matter, which held that this process was a commonplace and everyday occurrence, as distinguished from univocal generation, or reproduction from parent(s). Falsified by an elegant experiment by Louis Pasteur—where apparently spontaneous generation of microorganisms occurred, it did not happen on repeating the process without access to unfiltered air; on then opening the apparatus to the atmosphere, bacterial growth started.
Transmutation of species, Lamarckism, inheritance of acquired characteristics - first theories of evolution. Not supported by experiment, and rendered obsolete by Darwinian evolution, Mendelian genetics and epigenetics (although some elements of Lamarckian evolution are coming back in the area of epigenetics).
Mendelian genetics, classical genetics, Boveri–Sutton chromosome theory - first genetical theories. Not invalidated as such, but subsumed into molecular genetics.
Maternal impression – the theory that the mother's thoughts created birth defects. No experimental support (a notion rather than a theory), and rendered obsolete by genetic theory (see also fetal origins of adult disease, genomic imprinting)
Miasma theory of disease – the theory that diseases are caused by "bad air". No experimental support, and rendered obsolete by the germ theory of disease.
Preformationism – the theory that all organisms have existed since the beginning of life, and that gametes contain a miniature but complete preformed individual. No support when microscopy became available. Rendered obsolete by cytology, discovery of DNA, and atomic theory.
Recapitulation theory – the theory that "ontogeny recapitulates phylogeny". See Baer's laws of embryology.
Telegony – the theory that an offspring can inherit characteristics from a previous mate of its mother's as well as its actual parents, often associated with racism.
Vitalism – the theory that living things are alive because of some "vital force" independent of nonliving matter, as opposed to because of some appropriate assembly of nonliving matter. It was gradually discredited by the rise of organic chemistry, biochemistry, and molecular biology, fields that failed to discover any "vital force". Friedrich Wöhler's synthesis of urea from ammonium cyanate was only one step in a long road, not a great refutation.
Out of Asia theory of human origin – The majority view is of a recent African origin of modern humans, although a multiregional origin of modern humans hypothesis has much support (which incorporates past evidence of Asian origins)
Chemistry
Caloric theory - the theory that a self-repelling fluid called "caloric" was the substance of heat. Rendered obsolete by the mechanical theory of heat.
Classical elements - All matter was once thought to be composed of various combinations of classical elements (most famously air, earth, fire, and water). This was finally refuted by Antoine Lavoisier's publication of Elements of Chemistry, which contained the first modern list of chemical elements, in 1789.
Phlogiston theory – replaced by Lavoisier's work on oxidation
Points two and three of Dalton's Atomic Theory
Vitalism - See section on biology.
Physics
Emission theory of vision – discredited by Ibn al-Haytham (Alhacen)
Aristotelian physics – superseded by Newtonian physics
Ptolemy's law of refraction, replaced by Snell's law
Luminiferous aether – failed to be detected by the sufficiently sensitive Michelson-Morley experiment, made obsolete by Einstein's work.
Caloric theory – Lavoisier's successor to phlogiston, discredited by Rumford's and Joule's work
Vis viva – Gottfried Leibniz's elementary and limited early formulation of the principle of conservation of energy
"Purely electrostatic" theories of the generation of voltage differences.
Emitter theory – another now-obsolete theory of light propagation.
Progression of atomic theory
Democritus, the originator of atomic theory, held that everything is composed of atoms, which are indestructible
John Dalton's model of the atom, which held that atoms are indivisible and indestructible (superseded by nuclear physics) and that all atoms of a given element are identical in mass (superseded by discovery of atomic isotopes).
Plum pudding model of the atom—assuming the protons and electrons were mixed together in a single mass
Rutherford model of the atom with an impenetrable nucleus orbited by electrons
Bohr model with quantized orbits
Electron cloud model following the development of quantum mechanics in 1925 and the eventual atomic orbital models derived from the quantum mechanical solution to the hydrogen atom
All of classical physics, including Newtonian physics, superseded by relativistic physics and quantum physics. However, classical physics is a limiting case of the latter two theories, and it is often a very good approximation.
Astronomy and cosmology
Ptolemaic system – replaced by Nicolaus Copernicus' Heliocentric model.
Geocentric universe – made obsolete by Copernicus
Heliocentric universe – made obsolete by discovery of the structure of the Milky Way. Heliocentrism only applies to the Solar System, and only approximately, since the Sun's center is not at the Solar System's center of mass.
Copernican system – made obsolete by Johannes Kepler and Isaac Newton
Newtonian gravity – superseded by general relativity, to which it is an excellent approximation unless typical speeds approach that of light in a vacuum (c). The anomalous perihelion precession of Mercury was the first observational evidence that Newtonian gravity was not totally accurate.
Luminiferous aether theory
Steady State Theory, a model developed by Hermann Bondi, Thomas Gold, and Fred Hoyle whereby the expanding universe was in a steady state, and had no beginning. It was a competitor of the Big Bang model until evidence supporting the Big Bang and falsifying the steady state was found.
Geography and climate
Flat Earth theory. On length scales much smaller than the radius of the Earth, a flat map projection gives a quite accurate and practically useful approximation to true distances and sizes, but departures from flatness become increasingly significant over larger distances.
Terra Australis
Hollow Earth theory
The Open Polar Sea, an ice-free sea once supposed to surround the North Pole
Rain follows the plow – the theory that human settlement increases rainfall in arid regions (only true to the extent that crop fields evapotranspirate more than barren wilderness)
Geology
The following were superseded by Plate tectonics:
Expanding Earth theory (superseded by subduction)
Geosyncline theory
The theory of continental drift was incorporated into and improved upon by plate tectonics
Catastrophism was largely replaced by uniformitarianism
Neptunism replaced by Plutonism
Psychology
Pure behaviorist explanations for language acquisition in infancy, falsified by the study of cognitive adaptations for language.
Medicine
Theory of the four bodily humours (see also Four temperaments)
Eclectic Medicine – Transformed into alternative medicine, and is no longer considered a scientific theory.
Physiognomy, related to phrenology, held that inner character was strongly correlated with physical appearance.
Obsolete branches of enquiry
Alchemy, which led to the development of chemistry
Astrology, which led to the development of astronomy
Phrenology, a pseudoscience
Numerology, a pseudoscience
Theories now considered incomplete
Here are theories that are no longer considered the most complete representation of reality, but are still useful in particular domains or under certain conditions. For some theories a more complete model is known, but in practical use the coarser approximation provides good results with much less calculation.
Atomic nuclei disintegrate at high energy.
Newtonian mechanics was extended by the theory of relativity and by quantum mechanics. Relativistic corrections to Newtonian mechanics are unmeasurably small at velocities not approaching the speed of light, and quantum corrections are usually negligible at atomic or larger scales; Newtonian mechanics is totally satisfactory in engineering and physics under most circumstances.
Classical electrodynamics is a very close approximation to quantum electrodynamics except at very small scales and low field strengths.
Bohr model of the atom was extended by the quantum mechanical model of the atom.
The formula known as Newton's sine-square law of air resistance for the force of a fluid on a body, though not actually formulated by Newton but by others using a method of calculation used by Newton, has been found incorrect and not useful except for high-speed hypersonic flow.
http://en.wikipedia.org/wiki/Superseded_scientific_theories