Ernst Mach

Ernst Mach
Era	20th-century philosophy
Region	Western Philosophy
School	Analytic philosophy, Philosophy of Science
Main interests	Epistemology, Logic, Philosophy of Science, Philosophy of mathematics
Notable ideas	Mach band

Ernst Mach (pronounced [max], see IPA) (February 18, 1838 – February 19, 1916) was a Bohemian-Austrian physicist and philosopher and is the namesake for the "Mach number" (also known as Mach speed) and the optical illusion known as Mach bands.

Biography

Ernst Mach was born in Chrlice (now part of Brno, Czech Republic). His grandfather was tutor to the Brethon noble family in Chrlice; his father graduated from Prague University and taught at Chrlice grammar school. Ernst was born to Johann and Josefa Mach in House no. 1 in Chrlice, in Chrlice castle. Some other sources state that his birthplace was Tuřany, but this was where the Chrlice registry office was situated.

Up to the age of 15 he was educated at home by his parents. He then joined a Gymnasium in Kroměříž and in 1855 the University of Vienna. There he studied mathematics, physics and philosophy, and received a doctorate in physics in 1860. His early work was focused on the Doppler effect in optics and acoustics. In 1864 he took a job as Professor of Mathematics in Graz, and in 1866 he was appointed as Professor of Physics. During that period Mach became interested also in the psychophysiology of sensory perception. In 1867 he took the chair of Professor of Experimental Physics at Charles-Ferdinand University, Prague, where he stayed for 28 years.

Bust of Mach in the Rathauspark (City Hall Park), Vienna, Austria.

In 1897 he suffered a stroke and in 1901 retired from the University and was appointed to the upper chamber of the Austrian parliament. On leaving that post in 1913 he moved to his son's home in Vaterstetten, near Munich where he continued writing books until his death.

Physics

Most of his studies in the field of experimental physics were devoted to interference, diffraction, polarization and refraction of light in different media under external influences. These studies were soon followed by his important explorations in the field of supersonic velocity. Mach's paper on this subject was published in 1877 and correctly describes the sound effects observed during the supersonic motion of a projectile. Mach deduced and experimentally confirmed the existence of a shock wave which has the form of a cone with the projectile at the apex. The ratio of the speed of projectile to the speed of sound v_p/v_s is now called the Mach number. It plays a crucial role in aerodynamics and hydrodynamics. He also contributed to cosmology the hypothesis known as Mach's principle.

Philosophy of science

Mach developed a philosophy of science which was influential in the 19th and 20th centuries. Mach held that scientific laws are summaries of experimental events, constructed for the purpose of human comprehension of complex data. Thus scientific laws have more to do with the mind than with reality as it exists apart from the mind. Some quotations from Mach's writings will illustrate his philosophy. These selections are taken from his essay The Economical Nature of Physical Inquiry, excerpted by Kockelmans (citation below).

The goal which it [physical science] has set itself is the simplest and most 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.

In accordance with this philosophy, Mach opposed Ludwig Boltzmann and others who proposed an atomic theory of physics. Since atoms are too small to observe directly, and no atomic model at the time was consistent, the atomic hypothesis seemed to Mach to be unwarranted, and perhaps not sufficiently "economical".

Mach had a direct influence on the Vienna Circle philosophers and the school of logical positivism in general. Albert Einstein called him the "forerunner of [the] Theory of relativity", though Mach would later, to Einstein's disappointment, reject Einstein's theory.

Mach's positivism was also influential on many Russian Marxists, such as Alexander Bogdanov. In 1908, Lenin wrote a philosophical work Materialism and Empirio-Criticism in which he criticized the views of "Russian Machists".

Bold text'

Italic text

1. REDIRECT [[

Insert text

{| class="wikitable"

|- ! header 1 ! header 2 ! header 3 |- | row 1, cell 1 | row 1, cell 2 | row 1, cell 3 |- | row 2, cell 1 | row 2, cell 2 | row 2, cell 3[[Insert non-formatted text here]][ == http://www.example.com link title == [[Image:[[Media:Example.jpg]]<math><nowiki>Insert formula here--75.90.84.254 (talk) 23:26, 28 November 2007 (UTC)

---

1. REDIRECT [[Insert text
   _{Superscript text}

Block quote

]]</math>]]]</nowiki>

|}]]==Psychology== In the area of sensory perception, he is best known for an optical illusion called the Mach band.

In theoretical psychology Mach's position on mediating structures is credited with inspiring B. F. Skinner's strongly inductive position which paralleled Mach's, but in the realm of psychology

References

• J. Kockelmans. Philosophy of science: the historical background. New York: The Free Press, 1968.
• M. Chiesa. Radical Behaviorism: the philosophy and the science.2005.
• J. Blackmore, R. Itagaki, and S. Tanaka (eds.). "Introduction". In Boston Studies in the Philosophy of Science. Vol. 218: Ernst Mach's Vienna.

External links

• Various Ernst Mach links
• Short biography and bibliography in the Virtual Laboratory of the Max Planck Institute for the History of Science
• Vladimir Lenin: Materialism and Empirio-Criticism