Feast of Johannes Kepler (November 15)   Leave a comment

Above:  A Stamp Depicting Johannes Kepler

Image in the Public Domain



German Lutheran Astronomer and Mathematician

My greatest desire is that I may perceive the God whom I find everywhere in the external world, in like manner also within and inside myself.

–Johannes Kepler


Geometry is one and eternal shining in the mind of God.



Mathematics is the language in which God has written the universe.

–Galileo Gailiei


Johannes Kepler comes to this, my Ecumenical Calendar of Saints’ Days and Holy Days, via The Episcopal Church.  His Episcopal feast day (since 2009), shared with Nicolaus Copernicus (1473-1543), is May 23.  On my Ecumenical Calendar, however, Copernicus shares a feast day with Gailieo Galilei (1564-1642).

The following two assertions are true:

  1. Our societies shape us.  We are products of our times.
  2. We shape our societies.  We help to make our times.

Kepler was both a product of his times and a shaper of the future.  He was, in many ways, ahead of his time, especially as he matured.

Kepler became a founder of modern astronomy.  He, a subject of the Holy Roman Empire, began his journey into revolutionizing science began at Weil der Stadt, where, on December 27, 1571, Catherine (Guldenmann) Kepler, from a formerly noble family, gave birth to our saint.  The Kepler family’s fortunes had been declining for some time; the father worked as a soldier.  When Johannes was four years old, he nearly went blind due to smallpox.  The condition damaged his eyesight permanently.

Kepler, who once aspired to the Lutheran ministry, became a mathematician and a scientist instead.  After graduating from Maulbronn with his Bachelor’s degree in 1588, he matriculated at Tübingen, from which he graduated with a Master’s degree in 1591.  At Tübingen Kepler studied the Copernican theory (heliocentrism), then a controversial idea, especially in ecclesiastical circles.  Kepler accepted heliocentrism and helped to shape modern astronomy.

Doing this entailed contradicting contemporary Christian orthodoxy, according to which the other planets, as well as the Moon and Sun, revolved around the Earth.  To accept the heliocentric model was allegedly to minimize sin, given the assumption that, the closer one moved toward the center (supposedly the Earth), the farther one moved away from God and the angels.  To place the Earth in orbit of the Sun was allegedly to place sinful humans amid God and the angels.

Kepler, professor of mathematics at Graz, starting in 1594, made his contribution.  Aside from mathematics, he also taught rhetoric and Virgil.  Our saint, who lived when the distinction between astronomy and astrology did not exist, prepared astrological almanacs.  Kepler, in the realm of faith and hard science, sought order in the relationships of planetary orbits to each other.  He initially had difficulty divorcing himself from all the assumptions of the old, accepted Ptolemaic model, with its spheres, et cetera.  Our saint married Barbara von Mühlbeck (d. 1611), of Graz, in April 1597.  A purge of Protestant theologians from that city in September of that year forced the Keplers to move.  Barbara’s wealth and influence enabled the couple to return after just one month, though.  They did have to leave in 1600, however.

The Keplers moved to Prague, for our saint’s new position, in 1600.  Tycho Brahe (1546-1601) helped to facilitate this transition.  Kepler became the court mathematician to Holy Roman Emperor Rudolf II (reigned 1576-1612).  Our saint, as an astrologer, created horoscopes for the Emperor and courtiers.  Kepler also studied and wrote about light reflection, supernovae, planetary orbits, and other topics in the realm of hard science.  Our saint, as the recipient of Tycho Brahe’s decades’ worth of astronomical observational notes, analyzed that data and in 1609, published his conclusion that planetary orbits were elliptical. Kepler contradicted the Ptolemaic model, according to which heavenly bodies moved in circular orbits.

Kepler, who remarried (to Susanna Reutlinger) in 1613, served loyally under Emperor Matthias (reigned 1612-1619), who appointed him the mathematician to the states of upper Austria in 1612.  The following year, Kepler and Matthias argued unsuccessfully for the adoption of the Gregorian Calendar, in lieu of the old Julian Calendar.  Science did not yet yield to Protestant anti-Roman Catholicism.

Kepler, who taught mathematics in Silesia from 1628 until his death at Regensberg on November 15, 1630, got much right and other theories wrong.  He practiced astrology, a pseudo-science.  Our saint also thought that comets did not return.  For that matter, Gaileo Gailiei, Kepler’s contemporary, did not accept the gravitational pull of the Moon on tides on the Earth.  Great men were not always correct.

We see farther than they did because we stand on their shoulders.

Kepler was not only a giant of science; he was also a devout Christian.  He was, in both regards, in the same league as Copernicus, Galilei, and Michael Faraday (1791-1867).

The conflict between religion and faith on one side and science on the other is unnecessary.  Truth is truth.  Bad theology is bad theology.  Good theology is good theology.  We can arrive at much truth via observation, experimentation, data analysis, documentation, et cetera–in other words, the Scientific Method and Enlightenment Modernism.  Other truth, however, resides in a different purview.  One can have access to truth via more than one channel.








As the heavens declare your glory, O God, and the firmament shows your handiwork,

we bless your Name for the gifts of knowledge and insight you bestowed upon Johannes Kepler,

and we pray that you would continue to advance our understanding of your cosmos,

for our good and for your glory;  through Jesus Christ, the firstborn of all creation,

who with you and the Holy Spirit lives and reigns, one God, for ever and ever.  Amen.

Genesis 1:14-19

Psalm 8

1 Corinthians 2:6-12

Matthew 2:1-11a

–Adapted from Holy Women, Holy Men:  Celebrating the Saints (2010), 383


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