Mach was born in Chrlice (German:Chirlitz),Moravia,Austrian Empire (now part ofBrno in theCzech Republic). His father Jan Nepomuk Mach, who had graduated fromCharles-Ferdinand University inPrague, acted as tutor to the noble Brethon family inZlín in eastern Moravia. His grandfather Wenzl Lanhaus, an administrator of the Chirlitz estate, was also master builder of the streets there. His activities in that field later influenced Ernst Mach's theoretical work. Some sources give Mach's birthplace as Tuřany (German:Turas, also part of Brno), the site of the Chirlitz registry office. It was there that Mach was baptized by Peregrin Weiss. Mach later became asocialist and anatheist,[6] but his theory and life were sometimes compared toBuddhism.Heinrich Gomperz called Mach the "Buddha of Science" because of hisphenomenalist approach to the "Ego" in hisAnalysis of Sensations.[7][8]
Self-Portrait by Ernst Mach (1886) featured in "Analysis of Sensations", also known as "view from the left eye"
Up to the age of 14, Mach was educated at home by his parents. He then entered agymnasium inKroměříž (German:Kremsier), where he studied for three years. In 1855, he became a student at theUniversity of Vienna, where he studiedphysics and for one semester medical physiology, receiving a doctorate in physics in 1860 underAndreas von Ettingshausen, with his thesisÜber elektrische Ladungen und Induktion and hishabilitation the following year. His early work focused on theDoppler effect inoptics andacoustics.
In 1864, Mach became professor of mathematics at theUniversity of Graz after having declined a chair in surgery at theUniversity of Salzburg. In 1866, he was appointed professor of physics. During this period, Mach continued his work inpsycho-physics and in sensory perception. In 1867, he took the chair of experimental physics atCharles-Ferdinand University, where he stayed for 28 years before returning to Vienna.[9] In 1871, he was elected a member of theRoyal Bohemian Society of Sciences.[10]
Mach's main contribution to physics involved his description and photographs of spark shock-waves and then ballistic shock-waves. He described how when a bullet or shell moved faster than the speed of sound, it created a compression of air in front of it. Usingschlieren photography, he and his son Ludwig photographed the shadows of the invisible shock waves. During the early 1890s, Ludwig invented a modification of theJamin interferometer that allowed for much clearer photographs.[9] But Mach also made many contributions to psychology and physiology, including his anticipation ofgestalt phenomena, his discovery of theoblique effect and ofMach bands, an inhibition-influenced type of visual illusion, and especially his discovery of anon-acoustic function of the inner ear that helps control human balance.
One of the best-known of Mach's ideas is the so-calledMach principle, the physical origin of inertia. This was never written down by Mach but was given a graphic verbal form, attributed byPhilipp Frank to Mach: "When the subway jerks, it's the fixed stars that throw you down."
Ernst Mach's historic 1887 photograph (shadowgraph) of a bow shockwave around a supersonic bullet[11]fired from aWerndl carbine.[12]
Mach was also well-known for his philosophy, developed in close interplay with his science.[a] He defended a type ofphenomenalism, recognizing onlysensations as real. That position seemed incompatible with the view of atoms and molecules as external, mind-independent things. After an 1897 lecture byLudwig Boltzmann at theImperial Academy of Science inVienna, Mach said, "I don't believe that atoms exist!"[14]
In 1898, Mach survived a paralytic stroke, and in 1901, he retired from the University of Vienna and was appointed to the upper chamber of the Austrian Parliament. On leaving Vienna in 1913, he moved to his son's home inVaterstetten, nearMunich, where he continued writing and corresponding until his death in 1916, one day after his 78th birthday.[9]
Born to a liberal family, Mach lamented that a "very reactionary-clerical" period followed the1848 revolutions, prompting him to plan to emigrate to America, although he never did.[15]
In 1901, Mach accepted an appointment to the AustrianHouse of Lords but declined a nobility because he thought it inappropriate for a scientist to accept such a thing.[16] He was on good personal terms with the Social Democrat politicianViktor Adler[17] and left money in his will to the Social Democrat newspaperArbeiter-Zeitung.[18]
Mach was critical of the European powers' colonial conquests, saying that they "will constitute...the most distasteful chapter of history for coming generations".[19]
Most of Mach's initial studies in experimental physics concentrated on theinterference,diffraction,polarization andrefraction of light in different media under external influences. From there followed explorations insupersonic fluid mechanics. Mach and physicist-photographerPeter Salcher presented their paper on this subject[20] in 1887; it correctly describes the sound effects observed during the supersonic motion of aprojectile. They deduced and experimentally confirmed the existence of ashock wave of conical shape, with the projectile at the apex.[21] The ratio of the speed of a fluid to the localspeed of soundvp/vs is called theMach number after him. It is a critical parameter in the description of high-speed fluid movement inaerodynamics andhydrodynamics. Mach also contributed tocosmology the hypothesis known asMach's principle.[9]
From 1895 to 1901, Mach held a newly created chair for "the history and philosophy of the inductive sciences" at the University of Vienna.[b] In his historico-philosophical studies, Mach developed a phenomenalisticphilosophy of science that became influential in the 19th and 20th centuries,empirio-criticism, a rigorouslypositivist and radicallyempiricist philosophy established by the German philosopherRichard Avenarius and further developed by Mach,Joseph Petzoldt, and others, according to which all we can know is our sensations.[22]
Mach originally saw scientific laws as summaries of experimental events, constructed for the purpose of making complex data comprehensible, but later emphasized mathematical functions as a more useful way to describe sensory appearances. Thus, scientific laws, while somewhat idealized, have more to do with describing sensations than with reality as it exists beyond sensations:
The goal which it (physical science) has set itself is thesimplest andmost economical abstract expression of facts.
When the human mind, with its limited powers, attempts to mirror in itself the rich life of the world, of which it itself is only a small part, and which it can never hope to exhaust, it has every reason for proceeding economically.
In reality, the law always contains less than the fact itself, because it does not reproduce the fact as a whole but only in that aspect of it which is important for us, the rest being intentionally or from necessity omitted.
In mentally separating a body from the changeable environment in which it moves, what we really do is to extricate a group of sensations on which our thoughts are fastened and which is of relatively greater stability than the others, from the stream of all our sensations.
Suppose we were to attribute to nature the property of producing like effects in like circumstances; just these like circumstances we should not know how to find. Nature exists once only. Our schematic mental imitation alone produces like events.[c]
If bodies are "complexes of sensations," as Mach says, or "combinations of sensations," as Berkeley said, it inevitably follows that the whole world is but my idea. Starting from such a premise it is impossible to arrive at the existence of other people besides oneself: it is the purest solipsism....if [Mach] does not admit that the "sensible content" is an objective reality, existing independently of us, there remains only a "naked abstract" I, an I infallibly written with a capital letter and italicised, equal to "the insane piano, which imagined that it was the sole existing thing in this world." If the "sensible content" of our sensations is not the external world, then nothing exists save this naked I engaged in empty "philosophical" acrobatics.
— Chapter 1.1, "Sensations and Complexes of Sensations"
In accordance with empirio-critical philosophy, Mach opposedLudwig Boltzmann and others who proposed an atomic theory of physics. Since one cannot observe things as small as atoms directly, and since no atomic model at the time was consistent, the atomic hypothesis seemed unwarranted to Mach, and perhaps not sufficiently "economical". Mach had a direct influence on theVienna Circle philosophers andlogical positivism in general.
Any phenomena that seem attributable to absolute space and time (e.g.,inertia andcentrifugal force) should instead be seen as emerging from the distribution of matter in the universe.[26]
The last is singled out, particularly by Einstein, as "the"Mach's principle. Einstein cited it as one of the three principles underlyinggeneral relativity. In 1930, he wrote, "it is justified to consider Mach as the precursor of the general theory of relativity" and "the whole direction of thought of this theory conforms with Mach's".[27][28] Einstein further reported that he had readDavid Hume and Mach's work "with eagerness and admiration shortly before finding relativity theory" and that "very possibly, I wouldn't have come to the solution without those philosophical studies".[29] Before his death, Mach apparently rejected Einstein's theory.[e] Einstein knew his theories did not fulfill all Mach's principles, and no subsequent theory has either.[citation needed]
According to Alexander Riegler, Mach's work was a precursor to the influential perspective known asconstructivism.[30] Constructivism holds that all knowledge is constructed rather than received by the learner. He took an exceptionally non-dualist, phenomenological position. The founder of radical constructivism,Ernst von Glasersfeld, gave a nod to Mach as an ally.[citation needed]
Spinning chair devised by Mach to investigate the experience of motion
On the other hand, there is also a reasonable case for viewing Mach simply as an empiricist and a precursor of the logical empiricists and the Vienna Circle. On this view, the purpose of science is to detail functional relationships between observations: "The goal which it (physical science) has set itself is the simplest and most economical abstract expression of facts."[c]
Friedrich Hayek wrote that, when he attended theUniversity of Vienna from 1918 to 1921, "as far as philosophical discussion went it essentially revolved around Mach's ideas".[31] Mach's work has also been cited as an influence on theVienna Circle, being described as a "major precursor of logical positivism".[32] Members of the Circle organized the "Ernst Mach Society" as a vehicle for discussion of their ideas.[33]
In 1873, independently of each other,[35] Mach and the physiologist and physicianJosef Breuer discovered how thesense of balance (i.e., the perception of the head's imbalance) functions, tracing its management by information the brain receives from the movement ofa fluid in thesemicircular canals of theinner ear. That the sense of balance depends on the three semicircular canals was discovered in 1870 by the physiologistFriedrich Goltz, but Goltz did not discover how the balance-sensing apparatus functions. Mach devised a swivel chair to test his theories, and Floyd Ratliff has suggested that this experiment may have paved the way to Mach's critique of a physical conception of absolute space and motion.[36]
Exaggerated contrast between edges of the slightly differing shades of gray, appears as soon as they make contact
In the area of sensory perception, psychologists remember Mach for theoptical illusion calledMach bands. The effect exaggerates the contrast between edges of the slightly differing shades of gray as soon as they make contact, by triggering edge-detection in the human visual system.[9][37]
More clearly than anyone before or since, Mach made the distinction between what he calledphysiological (specificallyvisual) andgeometrical spaces.[38]
Mach's views on mediating structures inspiredB. F. Skinner's stronglyinductive position, which paralleled Mach's in the field of psychology.[39]
Mach, Ernst (1886).Beiträge zur Analyse der Empfindungen (in German). Jena: Gustav Fischer. (Later editions were published under the titleAnalyse der Empfindungen und das Verhältnis des Physischen zum Psychischen)
^On this interdependency of Mach's physics, physiology, history and philosophy of science seeBlackmore 1972, Blackmore (ed.) 1992 andHentschel 1985 against Paul Feyerabend's efforts to decouple these three strands.
^On Mach's historiography, cf., e.g.,Hentschel 1988 on his impact in Vienna, see Stadler et al. (1988), and Blackmore et al. (2001).
^abSelections are taken from his essayThe Economical Nature of Physical Inquiry, excerpted by Kockelmans and slightly corrected by Blackmore. (citation below).
^Barbour 2001, p. 220 states "In the Machian view, the properties of the system are exhausted by the masses of the particles and their separations, but the separations are mutual properties. Apart from the masses, the particles have no attributes that are exclusively their own. They — in the form of a triangle — are a single thing. In the Newtonian view, the particles exist in absolute space and time. These external elements lend the particles attributes — position, momentum, angular momentum — denied in the Machian view. The particles become three things. Absolute space and time are an essential part of atomism".
^The preface of the posthumously publishedPrinciples of Physical Optics explicitly rejects Einstein's relativistic views but it has been argued that the text is inauthentic.(Wolters 2012, pp. 39–57)
^Penrose 2016, p. 753: Mach's principle asserts that physics should be defined entirely in terms of the relation of one body to another, and that the very notion of a background space should be abandoned
^Mach 1919: [The] investigator must feel the need of ... knowledge of the immediate connections, say, of the masses of the universe. There will hover before him as an ideal insight into the principles of the whole matter, from which accelerated and inertial motions will result in the same way.
^Einstein, Albert (1973). Albert Einstein to Armin Weiner, September 18, 1930, unpublished letter from the Archives of the Burndy Library in Norwalk, Connecticut, cited by Holton, Gerald J. "Where is Reality? The Answers of Einstein." InScience and Synthesis, pp. 55. Edited by UNESCO. Berlin: Springer Verlag, 1971. Reprinted inThematic Origins of Scientific Thought: Kepler to Einstein. Cambridge: Mass.: Harvard University Press. p. 55.
Anderson, J. (1998), Mack, Pamela E. (ed.), "Research in Supersonic Flight and the Breaking of the Sound Barrier",From Engineering Science to Big Science: The NACA and NASA Collier Trophy Research Project Winners, NASA
Ratliff, Floyd (1975). "On Mach's Contributions to the Analysis of Sensations". In Seeger, Raymond J.; Cohen, Robert S. (eds.).Ernst Mach, Physicist and Philosopher.
Steila, Daniela (2013).Nauka i revoljucija. Recepciia empiriokriticizma v russkoi kul'ture (1877-1910 gg.) [Science and revolution. Reception of empiriocriticism in Russian culture] (in Croatian). Moscow: Akademicheskii Proekt.hdl:2318/141997.ISBN978-5-8291-1459-6.
John T. Blackmore, Ryoichi Itagaki and Setsuko Tanaka (eds.):Ernst Mach's Science. Kanagawa: Tokai University Press, 2006.
John T. Blackmore, Ryoichi Itagaki and Setsuko Tanaka:Ernst Mach's Influence Spreads. Bethesda: Sentinel Open Press, 2009.
John T. Blackmore, Ryoichi Itagaki and Setsuko Tanaka:Ernst Mach's Graz (1864–1867), where much science and philosophy were developed. Bethesda: Sentinel Open Press, 2010.
John T. Blackmore:Ernst Mach's Prague 1867–1895 as a human adventure, Bethesda: Sentinel Open Press, 2010.
Everdell, William (1997).The First Moderns. Profiles in the Origins of Twentieth-Century Thought. University of Chicago Press.
Haller, Rudolf; Stadler, Friedrich, eds. (1988).Ernst Mach – Werk und Wirkung (in German). Vienna: Hoelder-Pichler-Tempsky.