Superseded theories in science

In science, a theory is superseded when a scientific consensus once widely accepted it, but current science considers it an inadequate, incomplete, or debunked (i.e., wrong). Such labels do not cover protoscientific or fringe science theories that have never had broad support within the scientific community. Furthermore, superseded or obsolete theories exclude theories that were never widely accepted by the scientific community. Some theories that were only supported under specific political authorities, such as Lysenkoism, may also be described as obsolete or superseded.

The obsolete geocentric model places Earth at the centre of the Universe.

All of Newtonian physics is so satisfactory for most purposes, and so is widely used except at velocities that are a significant fraction of the speed of light. It is also simpler than relativistic mechanics and so is usually taught in schools. Another case is the belief that the Earth is approximately flat. For centuries, people have known that a flat Earth model produces errors in long-distance calculations, but considering local-scale areas as flat for the purposes of mapping and surveying does not introduce significant errors.

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.

Superseded theories

Scientific theories are testable and make falsifiable predictions.[1] Thus, it is a mark of good science if a discipline has a growing list of superseded theories, and conversely, a lack of superseded theories can indicate problems in following the use of the scientific method.

Biology
  • Spontaneous generation – a principle regarding the spontaneous generation of complex 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 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 and Mendelian genetics, though some elements of Lamarckian evolution are coming back in the area of epigenetics.
  • Vitalism – the theory that living things are alive because of some "vital force" independent of matter, as opposed to because of some appropriate assembly of 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.

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 composed of various combinations of classical elements (most famously air, earth, fire, and water). Antoine Lavoisier finally refuted this in his 1789 publication, Elements of Chemistry, which contained the first modern list of chemical elements.
  • Phlogiston theory – The theory that combustible goods contain a substance called "phlogiston" that entered air during combustion. Replaced by Lavoisier's work on oxidation
  • Point 2 of Dalton's Atomic Theory was rendered obsolete by discovery of isotopes, and point 3 by discovery of subatomic particles and nuclear reactions.
  • Vitalism – See section on biology.
  • Nascent state refers to the form of a chemical element (or sometimes compound) in the instance of their liberation or formation. Often encountered are atomic oxygen (Onasc) and nascent hydrogen (Hnasc), andchlorine (Clnasc) or bromine (Brnasc).[5]

Physics
  • Emission theory of vision – the belief that vision is caused by rays emanating from the eyes was superseded by the intro-mission approach and more complex theories of vision
  • 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
  • Contact tension – a theory on the source of electricity
  • 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
  • Balance of nature – superseded by catastrophe theory and chaos theory
  • Progression of atomic theory
    • Democritus, the originator of atomic theory, held that everything is composed of atoms that are indestructible. His claim that atoms are indestructible is not the reason it is superseded—as it was later scientists who identified the concept of atoms with particles, which later science showed are destructible. Democritus' theory is superseded because of his position that several kinds of atoms explain pure materials like water or iron, and characteristics that science now identifies with molecules rather than with indestructible primary particles. Democritus also held that between atoms, an empty space of a different nature than atoms allowed atoms to move. This view on space and matter persisted until Einstein described spacetime as being relative and connected to matter.
    • 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).[6]
    • 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 and the red shift of most galaxies. Heliocentrism only applies to the selected 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 a good 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.
  • Many planets and other objects were once thought to exist but are now known not to – see List of hypothetical Solar System objects

Geography and climate
  • Climatic determinism
  • Topographic determinism
  • Moral geography
  • Cultural Acclimatization

Geology

Psychology

Medicine

Obsolete branches of enquiry

Theories now considered incomplete

Here are theories that are no longer considered the most complete representation of reality, but remain 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.

  • Newtonian mechanics was extended by the theory of relativity and by quantum mechanics. Relativistic corrections to Newtonian mechanics are immeasurably small at velocities not approaching the speed of light,[11] and quantum corrections are usually negligible at atomic or larger scales;[12] 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.[13]
  • The once popular Cycle of erosion is now considered one of many possibilities for landscape evolution.[14]
  • The theory of continental drift was incorporated into and improved upon by plate tectonics.

See also

Lists

References
  1. Popper, Karl (1963), Conjectures and Refutations, Routledge and Kegan Paul, London, UK. Reprinted in Theodore Schick (ed., 2000), Readings in the Philosophy of Science, Mayfield Publishing Company, Mountain View, Calif.
  2. Executive Board of the American Anthropological Association. "scientific racism". AAA Statement on Race. American Anthropological Association. Retrieved 15 December 2018.CS1 maint: uses authors parameter (link)
  3. "germline theory". Glossary. NCBI.
  4. Lefers, Mark. "germ-line theory". Glossary. Northwestern University. Retrieved 28 February 2012.
  5. Jensen, William B (1990). "Whatever Happened to the Nascent State?" (PDF). Bulletin for the History of Chemistry (5): 26–36. Retrieved 6 May 2017.
  6. De Leon, Professor N. "Dalton's Atomic Theory". Chemistry 101 Class Notes. Indiana University Northwest. Retrieved 26 August 2013.
  7. Cathcart, Michael (2009). The Water Dreamers: How Water and Silence Shaped Australia. Melbourne: Text Publishing. chapter 7. ISBN 9781921520648.
  8. An inland sea, the Eromanga Sea, did exist there in the Mesozoic, but not during any period of human history
  9. Crain, Stephen and Diane C. Lillo-Martin (1999). An Introduction to Linguistic Theory and Language Acquisition. Oxford: Blackwell.
  10. Steven Novella, MD. "Psychomotor Patterning". Retrieved October 16, 2014.
  11. Hassani, Sadri (2010). From Atoms to Galaxies: A Conceptual Physics Approach to Scientific Awareness (illustrated ed.). CRC Press. p. 387. ISBN 978-1-4398-8284-9. Extract of page 387
  12. Casimir, H. B. G.; Brugt, Hendrik; Casimir, Gerhard (2010). Haphazard Reality: Half a Century of Science. Amsterdam University Press. p. 32. ISBN 978-90-8964-200-4. Extract of page 32
  13. Aerodynamics: Selected Topics in the Light of Their Historical Development,book by Theodore Von Karman, 1954, Dover Publications, p10 and following pages Detailed discussion of Newton's sine-square law, invalidity in the general case and applicability at high supersonic speeds.
  14. Orme, Anthony R. (2007). "The Rise and Fall of the Davisian Cycle of Erosion: Prelude, Fugue, Coda, and Sequel". Physical Geography. 28 (6): 474–506. doi:10.2747/0272-3646.28.6.474.
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