MYSTERIES OF THE EQUILATERAL TRIANGLE - HIKARI Ltd

156 Biographical Vignettes
He fell ill while visiting Regensburg, Bavaria and died, aged 58. (His tomb was
destroyed in the course of the Thirty Years’ War.) Somnium (1634), which
was published posthumously, aimed to show the feasibility of a non-geocentric
system by describing what practicing astronomy would be like from the perspective
of another planet. Kepler’s work on regular and semiregular tilings
of the plane was mentioned in Chapter 1 as was the likelihood that he was a
Rosicrucian. Source material for Kepler is available in [42].
Vignette 11 (René Descartes: 1596-1650).
René Descartes, the Father of Modern Philosophy, was born in La Haye
en Touraine (now renamed Descartes), Indre-et-Loire, France [3]. He was educated
at the Jesuit College of La Flèche in Anjou until 1612. He received a
law degree from the University of Poitiers in 1616 and then enlisted in the military
school at Breda in the Dutch Republic. Here he met the Dutch scientist
Isaac Beeckman with whom he began studying mechanics and Mathematics in
1618, then, in 1619, he joined the Bavarian army. From 1620 to 1628, he wandered
throughout Europe, spending time in Bohemia (1620), Hungary (1621),
Germany, Holland and France (1622-23). In 1623, he met Marin Mersenne in
Paris, an important contact which kept him in touch with the scientific world
for many years. From Paris, he travelled to Italy where he spent some time in
Venice, then he returned to France again (1625). In 1628, he chose to settle
down in Holland for the next twenty years. In 1637, he published a scientific
treatise, Discours de la méthode, which included a treatment of the tangent
line problem which was to provide the basis for the calculus of Newton and
Leibniz. It also contained among its appendices his masterpiece on analytic
geometry, La Géométrie, which includes Descartes’ Rule of Signs for determining
the number of positive and negative real roots of a polynomial. In another
appendix, on optics, he independently discovered Snell’s law of reflection. In
1644, he published Principia Philosophiae where he presented a mathematical
foundation for mechanics that included a vortex theory as an alternative to
action at a distance. In 1649, Queen Christina of Sweden persuaded him to
move to Stockholm, where he died of pneumonia, aged 53. Descartes’ proficiency
at bare-knuckled brawling is revealed by his response to criticism of his
work by Fermat: he asserted euphemistically that he was “full of shit” [169, p.
38]. Descartes’ role in the discovery of the polyhedral formula was mentioned
in Chapter 1 as was the likelihood that he was a Rosicrucian. Source material
for Descartes is available in [42, 77, 221, 287, 297].
Vignette 12 (Pierre de Fermat: 1601-1665).
Pierre de Fermat, lawyer and Mathematician, was born in Beaumont-de-
Lomagne, France [216]. He began his studies at the University of Toulouse