Lecture 5
Scientific Method
Case Study: Astronomy
Dr. Ann T. Orlando
October 2, 2008
Outline
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Ancient cosmology and physics
Augustine’s cosmology
Aquinas’ physics
Galileo and the aftermath
What did Augustine (and Church) really
teach?
Aristotle and Greek Physics
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Aristotle (384-322 BC), wrote On Physics
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All physical things made of matter and form
All things through velocity seek their own level
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Metaphysics was treatise after physics that considered nonmaterial things
Velocity defined as inversely proportional to density of medium
through which a body travels
Vacuums cannot exist
World is eternal
Region above sun is unchanging
Observations of nature (empiricism) important to know how to
categorize particulars
Ptolemy and Greek Astronomy
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Ptolemy (85-165 AD)
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Worked in Alexandria as part of
Aristotelian school there
Synthesized astronomical
observations into mathematical
computations
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Wrote Almagest
Epicycles to describe notion
about a stationary earth
No vacuums
Lunar light reflected from sun
Very accurately predict eclipses
of sun, moon, planets
Also wrote Geography that
included accurate estimate of
earth’s diameter
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13th C Manuscript
http://www.ibiblio.org/expo/vatican.exhibit/exhibi
t/d-mathematics/Greek_astro.html
Augustine’s Physics
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Understanding natural world important to
Augustine
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When does he begin to doubt Manichees?
Basically he accepts the AristotelianPtolemaic world view of geography and
astronomy
Knows the earth is round, lunar light is
reflected from sun, planetary order and
epicycles
Significance of Physics in Augustine
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Understanding Genesis
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Cosmos not eternal but created ex nihilo
What is time
What is formless matter
What is relation between heavens and
Heaven
Aquinas and Physics
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Wrote a commentary on Aristotle’s On
Physics
For the most part accepted Aristotle-Ptolemy
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Notable exception: definition of velocity as time
rate of change of distance
Used Aristotle as primary philosophical tool
in theology
Excursus: Columbus (1451-1506)
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Recall reading ST Ia Q1
Did Europeans in general, or Church in
particular, think the world was flat?
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Why are we so often taught this now
No one tried to sail from Europe to China
because did not have the technology
Copernicus (1473-1543)
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Assisted Vatican on revision of calendar
Published De Revolutionibus shortly before
his death
Hypothesizes a heliocentric system
Galileo (1564-1642)
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Impact of Telescope
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Mathematical simplicity of heliocentric system very appealing
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Circular orbits
Note Galileo’s contributions to physics far beyond astronomy
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Becomes obvious that entities above the sun do change
Far more variety in celestial sphere than previously imagined
Dynamics (pendula)
Motion (weight not relevant to speed at which a body falls, Tower
of Pisa experiment)
But most of all using mathematics to describe laws of physics
Reaction against Aristotelianism
St. Robert Bellarmine (1542-1621)
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Concerned about interpretation of Scripture,
especially Joshua 10
Heliocentric system okay to make math
easier, draws distinction between easier
math and reality
But also concerned that circular-orbit
heliocentric system not as accurate as
epicycles and geocentric system
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And he was right
Galileo vs Church
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Conflict begins during Pope Paul V pontificate
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1616 “Copernicanism” condemned,
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Admirer of Galileo
1632 Galileo publishes Diologue Concerning the Two Chief World
Systems, Ptolemaic and Copernican
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De Revolutionibus placed on index
Galileo told not to teach it
1623 Maffeo Barberini becomes Pope Urban VIII
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Background of Reformation and Council of Trent
Published with approval of censors in Rome and Florence
Made fun of Pope, who saw himself as Simplicio, defender of Ptolemy
1633 Galileo brought before Inquisition
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House arrest
Allowed to return to Florence after recanting
Resolution of the Physics:
Elliptical Orbits
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By carefully analyzing data, Kepler
concludes that orbits are elliptical
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Mathematics of three laws of planetary motion
Description at
http://csep10.phys.utk.edu/astr161/lect/history/kepler.html
Enlightenment Mythology of Galileo
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“Despite all its enlightenment about other
matters, the eighteenth century was almost a
golden age for the invention and diffusion of
myths about Galileo’s trial.” – Finocchiaro,
Retrying Galileo, 111
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Galileo held in prison
Galileo had his eyes gauged out
Galileo had to live on bread and water
Situation Today:
Benedict XVI and Sapienza
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20th and 21st Centuries no strangers to embellishing Galileo
affair
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Bertold Brecht, Galileo, expands on clash of faith and reason
Most recently the controversy around Pope Benedict XVI
planned visit to Sapienza University in January 2008
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Physics faculty protest Pope’s visit because of reputed comments
he made in 1992 about Galileo; ‘authoritative’ reference was a
wikipedia article
Pope cancels visit
Rector of Sapienza eventually acknowledges criticism misdirected,
and invites Pope to return
Augustine, On Literal Interpretation of
Genesis
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Augustine wrote many works with Genesis as the focus
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De Genesi ad litteram liber written between 399-415
Understanding what Augustine meant by ‘literal’ meaning of Genesis
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Exegesis that is not figurative of Christ (not typological)
May include symbolic understanding; e.g. days of creation
Twelve books, divided into three parts
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Confessions Books XI-XIII
Against the Manichees
Against Faustus
Part 1: Books 1-5; days of creation
Part 2: Books 6-11; commentary on Genesis 2-3; expulsion form paradise
Part 3: Book 12; experiencing paradise (types of ecstasy)
Readings from Part 1
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1.18.36-19.39 and 2.9.20-2.10.23 and 2.18.38
Thomas Aquinas,
Summa Contra Gentiles
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Relation between truth of observation and truth of faith very
important
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SCG written to provide arguments against unbelievers, 12611264
Written in four parts
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Aristotelian empiricism
Part I: Of God as He Is in Himself
Part II: Of God and Origin of Creatures
Part III: Of God the End of Creatures
Part IV: Of God in His Revelation
Read I.vii, “The Truth of Reason Is Not Contrary to Truth of
Faith”
Thomas Aquinas
Summa Theologiae
Ia 68 a1 and a3
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Question 68 begins in a1 with the proper way
to interpret Scripture according to Augustine
Does Aquinas go beyond Augustine in a3?
Galileo and Bellarmine
Letters in 1615
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Galileo, Letter to Grand Duchess Christina
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Written to important patron, Grand Duchess
Christina
Published more widely 1636
Bellarmine, Letter to Rev. Foscarini
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Rev. Foscarini was a Carmelite astronomer who
was a friend and supporter of Galileo
Voltaire," Preface” and “Authority”
Philosophical Dictionary
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Voltaire (1694-1778)
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Philosophical Dictionary
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Leading light of French Enlightenment (philosophe)
Deist
Wrote extensively on history, physics, religion, art in many
genres (poems, articles, treatises, plays)
Published 1764
Part of program of philsosphes to provide knowledge free
from influences of superstition (religion)
Available at
http://www.gutenberg.org/catalog/world/readfile?pag
eno=24&fk_files=237218
John Paul II:
Address to Pontifical Academy of
Sciences
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Address given Oct 31, 1992
Pope charged the Academy of Sciences with
reevaluating the Galileo Affair
Similar address in 1996 on evolution,
http://www.catholic.net/RCC/Periodicals/Insid
e/01-97/creat2.html
Assignment
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Augustine, On Literal Interpretation of Genesis, 1.18.36-19.39 and
2.9.20-2.10.23 and 2.18.38
Aquinas, SCG available at
http://www2.nd.edu/Departments/Maritain/etext/gc1_7.htm
Aquinas, Ia Q68 a1 and a3
Galileo, Letter to Grand Duchess Christina,
Bellarmine, Letter to Rev. Foscarini,
http://www.fordham.edu/halsall/mod/galileo-tuscany.html
http://www.fordham.edu/halsall/mod/1615bellarmine-letter.html
Voltaire, “Authority,” Philosophical Dictionary, available at Project
Guttenburg, www.gutenberg.org pp 1 and 24-25.
JPII, http://www.its.caltech.edu/~nmcenter/sci-cp/sci-9211.html
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French, Italian and German versions available on Vatican website
How did Aquinas and Galileo use Augustine? How are preconceived
prejudices at work in reactions from Voltaire to today?