SCIENTIFIC REVOLUTION
I. Thomas Kuhn, The Structure of a Scientific Revolution
1) paradigm:
universally recognized model from which a
coherent tradition of scientific research originates;
set of rules or assumptions guiding ordinary science
e.g.: any basic text book account of a science
2) data: organized and given meaning by the paradigm;
without paradigm, data gathering is random procedure
3) anomalies: data which does not fit current paradigm;
growth of anomalies leads to search for new paradigm
II. Old World View
Aristotelian
Physics: explanations of motion
natural motion of matter (fire,
air, earth, water)
acceleration of falling
bodies (jubilancy, homecoming)
projectile motion: impossibility
of vacuum, rush of air
distinction between earthly
& heavenly motion
Ptolemaic universe:
(Ptolemy, 2cd century AD Greece)
geocentric, crystalline spheres which require mover,
angels turn spheres; music of the spheres
finite universe: boundary is primum mobile
boundary between sphere of earth (corruptible matter)
and heavens (incorruptible)
celestial motion is uniform & circular
Problem
of motion of planets in Ptolemaic astronomy
retrograde motion = anomaly, not uniform or circular
solution: epicycles, deferents, eccentric orbits
result: loss of "conceptual economy" Kuhn
III. Copernican Revolution: Nicolas Copernicus, Polish monk
Major work:
De revolutionibus orbium caelestium 1543
(On the revolutions of the heavenly sphere)
Revolutionary
proposals:
heliocentrism: rejects motion
of sun
motion of earth, no longer
central to universe
retrograde motion of planets
is optical illusion
Conservatism of Copernicus
insistence on circular
motion as more perfect
religious motivation: to
display divine order
desire for single all encompassing
explanation
Opposition
to heliocentrism: common sense
Scripture: condemned by Protestants & Catholics
threatens entire Christian cosmology (world view)
Galileo
Galilei (1584-1642)
Astronomy: popularizer of Copernican system
1609 telescope: qualitatively new data:
views new stars, sun spots (corruptibility),
moons of Jupiter, phases of Venus
1625 Dialogue on Two Chief World Systems:
attack on Ptolemy & Aristotle;
first major public defense of Copernican system
1630-33
trial by Roman Inquisition, required to abjure
heresy of Copernicanism, house arrest in Florence;
reported to have said under his breath after recanting
"Eppure si muove." -- "And
yet it does move."
Physics: mathematical descriptions of types of motion
falling bodies: writes equation describing effects
of gravity,
but cause not understood; no theory of gravity
until Newton
inertial motion: to explain planetary motion, posits
circular inertia (wrong but introduces
idea of inertia)
Issac
Newton
1687 Principia Mathematica: gravity as common principle
underlying earthly and heavenly motion; all motion can be
mathematically described through the calculus