Kepler was a brilliant mathematician and astronomer. He did early work on light, and established the laws of planetary motion about the sun. He also came close to reaching the Newtonian concept of universal gravity - well before Newton was born! His introduction of the idea of force in astronomy changed it radically in a modern direction. Kepler was an extremely sincere and pious Lutheran, whose works on astronomy contain writings about how space and the heavenly bodies represent the Trinity. Kepler suffered no persecution for his open avowal of the sun-centered system, and, indeed, was allowed as a Protestant to stay in Catholic Graz as a Professor (1595-1600) when other Protestants had been expelled!From: Dan Graves, Scientists of Faith, Kregel Resources: Grand Rapids, MI (1996), pages 46-48:
[Sources:] M. Caspar, Kepler (1994), J. Banville, Kepler (1990)
The founder of modern astronomy... His real dream was to enter the ministry, but economic necessity forced him to pursue mathematics. He would later recognize God's leading in the academic route he followed... Harrassment over his religious beliefs compelled him to leave Gratz [Austria] in 1597. He spent some time in Prague, but community opposition to his Lutheranism eventually drove him from there as well. The persecution led him to his big break. Kepler began working with Tycho Brahe...
[page 48] All of Kepler's writings and letters displayed deep religious convictions. He held that Scripture used the common expressions of mankind when it spoke about mundane things as opposed to spiritual mattes. Hence, he perceived the Bible to be a spiritual and not a scientific guide. He held reason to be above authority in matters of natural philosophy, while authority (that is, church and Scripture) ruled in matters of religion. Beneath it all, he saw himself as a priset of nature whose discoveries glorified the name of God.
Firmly believing that God created the universe, Kepler sought to discover how it was set in motion. "I wanted to become a theologian," he wrote. "For a long time I was restless. Now, however, behold how through my effort God is being celebrated in astronomy."
As a Lutheran working in areas controlled by Catholics, he suffered pangs of conscience when forced to make compromises. When Mysterium cosmographicum was printed, Kepler's school requested he delte passages referring to Scripture. He did so, but in a short tract explained his view on the relationship of Scripture to science. Unfortunately, Galileo borrowed from it freely and without attribution so that it came to be reprinted as his own work.
Johannes Kepler: Studied at Adelberg monastery school (lower seminary). Religious Affiliation: Lutheran. We've found nothing notable, either in terms of heterodoxy or devotion. [Source: The Galileo Project (http://galileo.rice.edu/Catalog/NewFiles/kepler.html)].
From: Raymond J. Seeger, "Kepler, Peaceful Protestant" in The Journal of the American Scientific Affiliation, 37 (June 1985): 93-96 (http://www.asa3.org/ASA/PSCF/1985/JASA6-85Seeger3.html; viewed 26 September 2005):
Johannes Kepler (1571-1630) was a rare and strange man whose life was fraught with vicissitudes stemming from the Diet of Augsburg (155 5) with its principle "cuius regio, eius religio" to the devastating Thirty Years War (1618-1648). He was born of Lutheran parents (father a soldier, mother daughter of an innkeeper) in Weil der Stadt, Wfirttemberg. At seven he was sent to a cloister Latin school and at thirteen to a seminary, from which he received a B.A. Two years later he was awarded an M.A. from the protestant University of TUbingen, which he had entered at eighteen to become a Lutheran priest. In the middle of the third year of his subsequent theological preparation the faculty recommended him to be teacher of mathematics and astronomy at the protestant seminary in Graz, Austria, where he was also appointed District Mathematician. (He married at twenty-six.) At twenty-eight he met the Danish astronomer Tycho Brahe (1546-1601) at Prague. Not being a Catholic, he was banished the following year. At thirty he began collaborating with Brahe on the Rudolphine Tables. In that very year, however, Brahe died; Rudolph 11 appointed Kepler to succeed him as Imperial Mathematician. Only his wife's income saved him from the embarassment of uncertain salary payments. Upon the Emperor's forced abdication in 1612 and his own refusal to become a Catholic, he had to seek employment elsewhere again, this time as District Mathematician in Linz. (His wife having died, he remarried-a happier venture.)... His outstanding characteristic, however, was his integrity resulting in sincere and frank behaviour. He was conscientious; agreeing with the new Gregorian calendar (1582), he did not side with the protestant opposition, which lasted until about 1700. Despite his personal political problems he never resorted to religious agitation; he was always urging peace. Himself modest, he recommended that jealous observers share their observations of an eclipse. He had a noble spirit; he was deeply religious...
A Platonist, Kepler was a mathematical mystic. He believed that "everything in nature is arranged according to measure and number." He was convinced that "the geometrical natures of things have provided the Creator the model for decorating the whole world." (He investigated the regularity of the six angles of a snowflake in "Strena" (1611),) His axiom was that "nothing in the world was created by God without a plan"; he sought it diligently.
Kepler's official duties included preparation of ephemerides and calendars, involving weather predictions and astrological notes. He was the first to place the birth of Jesus at 4 B.C... As for any influences of the stars, he exercised restraint and caution -- he recognized their general psychic effects, but avoided specific predictions. He seized the opportunity to give moral admonitions, to urge peaceful practices.
Kepler wrote occasional papers on theology, but he never claimed to be a theologian. He regarded himself as a layman who was a mathematician, a (natural) philosopher, a historian. And yet, he was probably the scientist who par excellence regarded science and religion as different aspects of an integrated world-not an artificial, academic bifurcation. The goal of science, he believed, is to bring man to God; the principle of his scientific work is praise of God. "We astronomers are priests of the highest God in regard to the book of nature." "God is the beginning and end of scientific research and striving"-the keynote of his thought, the basis of his purpose, the "life-giving soil of his feeling." For him, "geometry is unique and eternal, a reflection of the mind of God. That mankind shows in it is because man is an image of God."
Kepler regarded the Copernican theory as literally true -- not a convenient fiction. With respect to questionable Biblical passages (e.g. Josh. 10: 12, Ps. 104, Job 34), he noted, "It is not the purpose of the Holy Scriptures to instruct men in natural things." Despite his exemplary life, he was denied communion by his own Lutheran church, first at Graz, finally by Tffbingen in answer to his formal petition. Although he subscribed wholeheartedly to the Augsburg Confession (15 30), he could not quite endorse the Book of Concord (1580) because of its doctrine of the omnipresence of Christ (e.g., in the sacrament). He preferred the Calvinistic emphasis upon remembrance, but could not accept its complementary insistence upon predestination. He regarded himself as a catholic (including Lutherans and Calvinists, as well as Roman Catholics), but he could not agree with the Papacy (e.g., it's idolatry, saints, et al.).
Kepler's scientific writings are interspersed with pertinent religious comments. The "Harmonices," his favorite work, begins and ends with an appropriate prayer, (it contains also explanations about Jesus Christ). The conclusion begins, "0 Thou, who by the light of nature increases in us the desire for the light of Thy mercy in order to be led by this to Thy glory, to Thee I offer thanks, Creator, God, because Thou hast given me pleasure in what Thou hast created and I rejoice in Thy handiwork." His dying words were: "Only the merits of our saviour Jesus Christ. It is in Him, as I steadfastly testify, that there rest all my retreat, all my consolation, all my hope."