View source for The Unreasonable Effectiveness of Mathematics in the Natural Sciences

{{short description|1960 article by Eugene Wigner}}
"'''The Unreasonable Effectiveness of Mathematics in the Natural Sciences'''" is a 1960 article by the [[Physicist|physicist]] [[Biography:Eugene Wigner|Eugene Wigner]].<ref>{{Cite journal|last1=Wigner|first1=E. P.|year=1960|title=The unreasonable effectiveness of mathematics in the natural sciences. Richard Courant lecture in mathematical sciences delivered at New York University, May 11, 1959|url=http://www.dartmouth.edu/~matc/MathDrama/reading/Wigner.html|journal=Communications on Pure and Applied Mathematics|volume=13|pages=1–14|bibcode=1960CPAM...13....1W|doi=10.1002/cpa.3160130102|archive-url=https://web.archive.org/web/20210212111540/http://www.dartmouth.edu/~matc/MathDrama/reading/Wigner.html|archive-date=2020-02-12}}</ref><ref>Note: Wigner's mention of Kellner and Hilleraas "... Jordan felt that we would have been, at least temporarily, helpless had an unexpected disagreement occurred in the theory of the helium atom. This was, at that time, developed by Kellner and by Hilleraas ..." refers to Georg W. Kellner ({{cite journal|doi=10.1007/BF01391720|title=Die Ionisierungsspannung des Heliums nach der Schrödingerschen Theorie|year=1927|last1=Kellner|first1=Georg W.|journal=Zeitschrift für Physik|volume=44|issue=1–2|pages=91–109|bibcode=1927ZPhy...44...91K|s2cid=122213875}}) and to [[Biography:Egil Hylleraas|Egil Hylleraas]].</ref> In the paper, Wigner observes that a [[Physics:Theoretical physics|physical theory]]'s [[HandWiki:Mathematics|mathematical]] structure often points the way to further advances in that theory and even to empirical predictions.

== Original paper and Wigner's observations ==

Wigner begins his paper with the belief, common among those familiar with mathematics, that mathematical concepts have applicability far beyond the context in which they were originally developed. Based on his experience, he writes, "it is important to point out that the mathematical formulation of the physicist's often crude experience leads in an uncanny number of cases to an amazingly accurate description of a large class of phenomena".<ref name=Wigner60p8>{{harvnb|Wigner|1960|loc=§Is the Success of Physical Theories Truly Surprising? p. 8}}</ref> He then invokes the fundamental [[Physics:Gravity|law of gravitation]] as an example. Originally used to model freely falling bodies on the surface of the earth, this law was extended on the basis of what Wigner terms "very scanty observations"<ref name=Wigner60p8/> to describe the motion of the planets, where it "has proved accurate beyond all reasonable expectations".<ref>{{harvnb|Wigner|1960|p=9}}</ref>

Another oft-cited example is [[Physics:Maxwell's equations|Maxwell's equations]], derived to model the elementary electrical and magnetic phenomena known as of the mid-19th century. The equations also describe radio waves, discovered by [[Biography:David Edward Hughes|David Edward Hughes]] in 1879, around the time of [[Biography:James Clerk Maxwell|James Clerk Maxwell]]'s death. Wigner sums up his argument by saying that "the enormous usefulness of mathematics in the natural sciences is something bordering on the mysterious and that there is no rational explanation for it". He concludes his paper with the same question with which he began:

<blockquote>The miracle of the appropriateness of the language of mathematics for the formulation of the laws of physics is a wonderful gift which we neither understand nor deserve. We should be grateful for it and hope that it will remain valid in future research and that it will extend, for better or for worse, to our pleasure, even though perhaps also to our bafflement, to wide branches of learning.<ref name=Wigner60p14>{{harvnb|Wigner|1960|p=14}}</ref>
</blockquote>

Wigner's work provided a fresh insight into both physics and the [[Philosophy:Philosophy of mathematics|philosophy of mathematics]], and has been fairly often cited in the academic literature on the [[Physics:Philosophy of physics|philosophy of physics]] and of mathematics. Wigner speculated on the relationship between the [[Philosophy:Philosophy of science|philosophy of science]] and the [[Philosophy:Foundations of mathematics|foundations of mathematics]] as follows:

<blockquote>It is difficult to avoid the impression that a miracle confronts us here, quite comparable in its striking nature to the miracle that the human mind can string a thousand arguments together without getting itself into contradictions, or to the two miracles of laws of nature and of the human mind's capacity to divine them.<ref>{{harvnb|Wigner|1960|p=7}}</ref></blockquote>

Later, [[Biography:Hilary Putnam|Hilary Putnam]] (1975) explained the aforementioned two "miracles" as necessary consequences of a realist (but not Platonist) view of the [[Philosophy:Philosophy of mathematics|philosophy of mathematics]].<ref>{{cite journal |first=Hilary |last=Putnam |title=What is Mathematical Truth? |journal=Historia Mathematica |volume=2 |pages=529–543 |year=1975 |doi=10.1016/0315-0860(75)90116-0 |issue=4 |doi-access=free }}<br/>Reprinted in {{cite book |first=Hilary |last=Putnam |title=Mathematics, Matter and Method: Philosophical Papers |publisher=Cambridge University Press |year=1975 |isbn=978-0-521-20665-5 |pages=[https://archive.org/details/mathematicsmatte0001putn/page/60 60–78] |volume=1 |url=https://archive.org/details/mathematicsmatte0001putn/page/60 }}</ref> But in a passage discussing [[Philosophy:Cognitive bias|cognitive bias]] Wigner cautiously called "not reliable", he went further:

<blockquote>The writer is convinced that it is useful, in epistemological discussions, to abandon the idealization that the level of human intelligence has a singular position on an absolute scale. In some cases it may even be useful to consider the attainment which is possible at the level of the intelligence of some other species.<ref>{{harvnb|Wigner|1960|p=12 Footnote 11}}</ref></blockquote>

Whether humans checking the results of humans can be considered an objective basis for observation of the known (to humans) universe is an interesting question, one followed up in both [[Philosophy:Cosmology|cosmology]] and the [[Philosophy:Philosophy of mathematics|philosophy of mathematics]].

Wigner also laid out the challenge of a cognitive approach to integrating the sciences:

<blockquote>A much more difficult and confusing situation would arise if we could, some day, establish a theory of the phenomena of consciousness, or of biology, which would be as coherent and convincing as our present theories of the inanimate world.<ref>{{harvnb|Wigner|1960|p=13}}</ref></blockquote>

He further proposed that arguments could be found that might

<blockquote>put a heavy strain on our faith in our theories and on our belief in the reality of the concepts which we form. It would give us a deep sense of frustration in our search for what I called 'the ultimate truth'. The reason that such a situation is conceivable is that, fundamentally, we do not know why our theories work so well. Hence, their accuracy may not prove their truth and consistency. Indeed, it is this writer's belief that something rather akin to the situation which was described above exists if the present laws of heredity and of physics are confronted.<ref name=Wigner60p14/></blockquote>

== Responses ==

Wigner's original paper has provoked and inspired many responses across a wide range of disciplines. These include [[Biography:Richard Hamming|Richard Hamming]]<ref name="hamming">{{Cite journal | last1 = Hamming | first1 = R. W.|  title = The Unreasonable Effectiveness of Mathematics | journal = The American Mathematical Monthly | volume = 87 | issue = 2 | pages = 81–90 | doi = 10.2307/2321982 | year = 1980 | url = https://math.dartmouth.edu/~matc/MathDrama/reading/Hamming.html| jstor = 2321982| hdl = 10945/55827}}</ref> in computer science, [[Biography:Arthur M. Lesk|Arthur Lesk]] in molecular biology,<ref name="lesk">{{Cite journal | last1 = Lesk | first1 = A. M. | title = The unreasonable effectiveness of mathematics in molecular biology | doi = 10.1007/BF03025372 | journal = The Mathematical Intelligencer | volume = 22 | issue = 2 | pages = 28–37 | year = 2000 | s2cid = 120102813 }}</ref>  [[Biography:Peter Norvig|Peter Norvig]] in data mining,<ref name="norvig">{{Cite journal | last1 = Halevy | first1 = A. | author-link1 = Alon Y. Halevy| last2 = Norvig | first2 = P. | author-link2 = Peter Norvig| last3 = Pereira | first3 = F. | doi = 10.1109/MIS.2009.36 | title = The Unreasonable Effectiveness of Data | journal = IEEE Intelligent Systems | volume = 24 | issue = 2 | pages = 8–12 | year = 2009 | s2cid = 14300215 | url = http://static.googleusercontent.com/media/research.google.com/en//pubs/archive/35179.pdf}}</ref>  [[Biography:Max Tegmark|Max Tegmark]] in physics,<ref name="tegmark"/> [[Biography:Ivor Grattan-Guinness|Ivor Grattan-Guinness]] in mathematics<ref name="ivor">{{Cite journal | last1 = Grattan-Guinness | first1 = I. | title = Solving Wigner's mystery: The reasonable (though perhaps limited) effectiveness of mathematics in the natural sciences | doi = 10.1007/BF02985373 | journal = The Mathematical Intelligencer | volume = 30 | issue = 3 | pages = 7–17 | year = 2008 | s2cid = 123174309 }}</ref> and Vela Velupillai in economics.<ref name="velupillai">{{Cite journal | last1 = Velupillai | first1 = K. V. | title = The unreasonable ineffectiveness of mathematics in economics | doi = 10.1093/cje/bei084 | journal = Cambridge Journal of Economics | volume = 29 | issue = 6 | pages = 849–872 | year = 2005 | citeseerx = 10.1.1.194.6586 }}</ref>

===Richard Hamming===
{{more citations|section|date=April 2022}}
Mathematician and Turing Award laureate [[Biography:Richard Hamming|Richard Hamming]] reflected on and extended Wigner's ''Unreasonable Effectiveness'' in 1980, mulling over four "partial explanations" for it.<ref name="hamming"/> Hamming concluded that the four explanations he gave were unsatisfactory. They were:

1. ''Humans see what they look for''. The belief that science is experimentally grounded is only partially true. Rather, our intellectual apparatus is such that much of what we see comes from the glasses we put on. Eddington went so far as to claim that a sufficiently wise mind could deduce all of physics, illustrating his point with the following joke: "Some men went fishing in the sea with a net, and upon examining what they caught they concluded that there was a minimum size to the fish in the sea."

Hamming gives four examples of nontrivial physical phenomena he believes arose from the mathematical tools employed and not from the intrinsic properties of physical reality.
* Hamming proposes that Galileo discovered the [[Biography:Galileo Galilei#Falling bodies|law of falling bodies]] not by experimenting, but by simple, though careful, thinking. Hamming imagines Galileo as having engaged in the following [[Thought experiment|thought experiment]] (the experiment, which Hamming calls "scholastic reasoning", is described in Galileo's book ''On Motion''.):

<blockquote><blockquote>Suppose that a falling body broke into two pieces. Of course the two pieces would immediately slow down to their appropriate speeds. But suppose further that one piece happened to touch the other one. Would they now be one piece and both speed up? Suppose I tie the two pieces together. How tightly must I do it to make them one piece? A light string? A rope? Glue? When are two pieces one?<ref>
{{cite web
 |first=Albert 
 |last=Van Helden
 |title=On Motion
 |work=The Galileo Project
 |url=http://galileo.rice.edu/sci/theories/on_motion.html
 |date=1995
 |access-date=16 October 2013
}}</ref></blockquote>

There is simply no way a falling body can "answer" such hypothetical "questions." Hence Galileo would have concluded that "falling bodies need not know anything if they all fall with the same velocity, unless interfered with by another force." After coming up with this argument, Hamming found a related discussion in Pólya (1963: 83-85).<ref>{{cite book |first1=George |last1=Pólya |author-link2=Leon Bowden|first2=Leon |last2=Bowden |author3=School Mathematics Study Group |title=Mathematical methods in science; a course of lectures |publisher=Stanford: School Mathematics Study Group |year=1963 |oclc=227871299 |series=Studies in mathematics |volume=11 }}</ref> Hamming's account does not reveal an awareness of the 20th century scholarly debate over just what Galileo did.{{clarification-needed|date=March 2018}}
</blockquote>

*The inverse square law of universal gravitation necessarily follows from the [[Physics:Conservation of energy|conservation of energy]] and of space having [[Physics:Spacetime|three dimensions]]. Measuring the exponent in the law of universal gravitation is more a test of whether space is [[Euclidean space|Euclidean]] than a test of the properties of the [[Physics:Gravitational field|gravitational field]].
*The inequality at the heart of the [[Physics:Uncertainty principle|uncertainty principle]] of [[Physics:Quantum mechanics|quantum mechanics]] follows from the properties of Fourier integrals and from assuming time invariance.<ref>{{cite journal |first1=Gerald B. |last1=Folland |first2=Alladi |last2=Sitaram |title=The Uncertainty Principle: A Mathematical Survey |journal=Journal of Fourier Analysis and Applications |volume=3 |issue=3 |pages=207–238 |year=1997 |doi=10.1007/BF02649110 |s2cid=121355943 }}<!-- Needs expert confirmation PDF available at Citeseer --></ref>
*Hamming argues that [[Biography:Albert Einstein|Albert Einstein]]'s pioneering work on [[Physics:Special relativity|special relativity]] was largely "scholastic" in its approach. He knew from the outset what the theory should look like (although he only knew this because of the [[Physics:Michelson–Morley experiment|Michelson–Morley experiment]]), and explored candidate theories with mathematical tools, not actual experiments. Hamming alleges that Einstein was so confident that his relativity theories were correct that the outcomes of observations designed to test them did not much interest him. If the observations were inconsistent with his theories, it would be the observations that were at fault.

2. ''Humans create and select the mathematics that fit a situation''. The mathematics at hand does not always work. For example, when mere [[Scalar (mathematics)|scalar]]s proved awkward for understanding forces, first vectors, then [[Tensor|tensor]]s, were invented.

3. ''Mathematics addresses only a part of human experience''. Much of human experience does not fall under science or mathematics but under the [[Philosophy:Value theory|philosophy of value]], including [[Philosophy:Ethics|ethics]], [[Social:Aesthetics|aesthetics]], and [[Philosophy:Political philosophy|political philosophy]]. To assert that the world can be explained via mathematics amounts to an act of faith.

4. ''[[Biology:Evolution|Evolution]] has primed humans to think mathematically''. The earliest lifeforms must have contained the seeds of the human ability to create and follow long chains of close reasoning.

===Max Tegmark===
A different response, advocated by physicist [[Biography:Max Tegmark|Max Tegmark]], is that physics is so successfully described by mathematics because [[Physics:Mathematical universe hypothesis|the physical world ''is'' completely mathematical]], isomorphic to a mathematical structure, and that we are simply uncovering this bit by bit.<ref name="tegmark">{{cite journal |title=The Mathematical Universe |year=2008 |first=Max |last=Tegmark |doi=10.1007/s10701-007-9186-9 |journal=Foundations of Physics |volume=38 |issue=2 |pages=101–150 |arxiv=0704.0646|bibcode = 2008FoPh...38..101T |s2cid=9890455 }}</ref><ref>{{cite book |first=Max |last=Tegmark |title=Our Mathematical Universe |publisher=Knopf |year=2014 |isbn=978-0-307-59980-3|title-link=Our Mathematical Universe }}</ref> The same interpretation had been advanced some years previously by Peter Atkins.<ref>{{cite book |first=Peter |last=Atkins |author-link=Peter Atkins |title=Creation Revisited |publisher=W.H.Freeman |year=1992 |isbn=978-0-7167-4500-6}}</ref> In this interpretation, the various approximations that constitute our current physics theories are successful because simple mathematical structures can provide good approximations of certain aspects of more complex mathematical structures. In other words, our successful theories are not mathematics approximating physics, but simple mathematics approximating more complex mathematics.

===Ivor Grattan-Guinness===
[[Biography:Ivor Grattan-Guinness|Ivor Grattan-Guinness]] found the effectiveness in question eminently reasonable and explicable in terms of concepts such as analogy, generalisation and metaphor.<ref name="ivor"/>

== See also ==
{{Columns-list|colwidth=30em|
*[[Philosophy:Cosmology|Cosmology]]
*[[Philosophy:Foundations of mathematics|Foundations of mathematics]]
*[[Biography:Mark Steiner|Mark Steiner]]
*[[Physics:Mathematical universe hypothesis|Mathematical universe hypothesis]]
*[[Philosophy:Philosophy of science|Philosophy of science]]
*[[Quasi-empiricism in mathematics]]
*[[Physics:Relationship between mathematics and physics|Relationship between mathematics and physics]]
*Scientific structuralism
*Unreasonable ineffectiveness of mathematics
*''[[Philosophy:Where Mathematics Comes From|Where Mathematics Comes From]]''
}}

== References ==
{{reflist|30em}}

== Further reading ==
{{refbegin}}
*{{cite journal |author=Sundar Sarukkai |title=Revisiting the 'unreasonable effectiveness' of mathematics |journal=Current Science |volume=88 |issue=3 |date=10 February 2005 |JSTOR=24110208}}
*{{cite journal |first=Alex |last=Kasman |title=Unreasonable Effectiveness |journal=Math Horizons Magazine |pages=29–31 |date=April 2003 |volume=10 |issue=4 |doi=10.1080/10724117.2003.12023669 |s2cid=218542870 |url=http://kasmana.people.cofc.edu/MATHFICT/mfview.php?callnumber=mf334}}, a piece of "mathematical fiction".
*{{cite book |first=Mark |last=Colyvan |chapter=Indispensability Arguments in the Philosophy of Mathematics |date=Spring 2015 |title=Stanford Encyclopedia of Philosophy |publisher=Metaphysics Research Lab, Stanford University |editor-first=Edward N. |editor-last=Zalta |chapter-url=http://plato.stanford.edu/entries/mathphil-indis/}}
*{{cite book |first=Sorin |last=Bangu |title=The Applicability of Mathematics in Science: Indispensability and Ontology |publisher=Plagrave MacMillan |location=London |year=2012 |isbn=978-0230285200 |series=New Directions in the Philosophy of Science}}
* {{cite magazine |last=Wolchover |first=Natalie |date=9 December 2019 |title=Why the Laws of Physics Are Inevitable |magazine=Quanta Magazine |url=https://www.quantamagazine.org/how-simple-rules-bootstrap-the-laws-of-physics-20191209/}}
{{refend}}

{{Industrial and applied mathematics}}

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[[Category:Thought experiments in physics]]

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