Part 2 (1/2)

[Footnote 50: Aquinas: _Summa Theologica_, pt. I, qu. 70, art. 2.

(_Op. Om. Caietani_, V, 179).]

An adequate explanation of the universe existed. Aristotle, Augustine, and the other great authorities of the Middle Ages, all upheld the conception of a central earth encircled by the seven planetary spheres and by the all embracing starry firmament. In view of the phrases used in the Bible about the heavens, and in view of the formation of fundamental theological doctrines based on this supposition by the Church Fathers, is it surprising that any other than a geocentric theory seemed untenable, to be dismissed with a smile when not denounced as heretical? Small wonder is it, in the absence of the present day mechanical devices for the exact measurement of time and s.p.a.ce as aids to observation, that the Ptolemaic, or geocentric, theory of the universe endured through centuries as it did, upheld by the authority both of the Church and, in essence at least, by the great philosophers whose works const.i.tuted the teachings of the schools.

CHAPTER II.

COPERNICUS AND HIS TIMES.

During these centuries, one notable scholar at least stood forth in open hostility to the slavish devotion to Aristotle's writings and with hearty appreciation for the greater scientific accuracy of ”infidel philosophers among the Arabians, Hebrews and Greeks.”[51] In his _Opus Tertium_ (1267), Roger Bacon also pointed out how inaccurate were the astronomical tables used by the Church, for in 1267, according to these tables ”Christians will fast the whole week following the true Easter, and will eat flesh instead of fasting at Quadragesima for a week--which is absurd,” and thus Christians are made foolish in the eyes of the heathen.[52] Even the rustic, he added, can observe the phases of the moon occurring a week ahead of the date set by the calendar.[53] Bacon's protests were unheeded, however, and the Church continued using the old tables which grew increasingly inaccurate with each year. Pope Sixtus IV sought to reform the calendar two centuries later with the aid of Regiomonta.n.u.s, then the greatest astronomer in Europe (1475);[54] the Lateran Council appealed to Copernicus for help (1514), but little could be done, as Copernicus replied, till the sun's and the moon's positions had been observed far more precisely;[55] and the modern scientific calendar was not adopted until 1582 under Pope Gregory XIII.

[Footnote 51: Roger Bacon: _Opus Tertium_, 295, 30-31.]

[Footnote 52: Ibid: 289.]

[Footnote 53: Ibid: 282.]

[Footnote 54: Delambre: _Moyen Age_, 365.]

[Footnote 55: Prowe: II, 67-70.]

What was the state of astronomy in the century of Copernicus's birth?

Regiomonta.n.u.s--to use Johann Muller's Latin name--his teacher Purbach, and the great cardinal Nicolas of Cues were the leading astronomers of this fifteenth century. Purbach[56] (1432-1462) died before he had fulfilled the promise of his youth, leaving his _Epitome of Ptolemy's Almagest_ to be completed by his greater pupil. In his _Theorica Planetarum_ (1460) Purbach sought to explain the motions of the planets by placing each planet between the walls of two curved surfaces with just sufficient s.p.a.ce in which the planet could move. As M. Delambre remarked:[57] ”These walls might aid the understanding, but one must suppose them transparent; and even if they guided the planet as was their purpose, they hindered the movement of the comets.

Therefore they had to be abandoned, and in our own modern physics they are absolutely superfluous; they have even been rather harmful, since they interfered with the slight irregularities caused by the force of attraction in planetary movements which observations have disclosed.”

This scheme gives some indication of the elaborate devices scholars evolved in order to cope with the increasing number of seeming irregularities observed in ”the heavens,” and perhaps it makes clearer why Copernicus was so dissatisfied with the astronomical hypothesis of his day, and longed for some simpler, more harmonious explanation.

[Footnote 56: Delambre: _Moyen Age_, 262-272.]

[Footnote 57: Delambre: _Moyen Age_, 272.]

Regiomonta.n.u.s[58] (1436-1476) after Purbach's death, continued his work, and his astronomical tables (pub. 1475) were in general use throughout Europe till superseded by the vastly more accurate Copernican Tables a century later. It has been said[59] that his fame inspired Copernicus (born three years before the other's death in 1476) to become as great an astronomer. M. Delambre hails him as the wisest astronomer Europe had yet produced[60] and certainly his renown was approached only by that of the great Cardinal.

[Footnote 58: It has been claimed that Regiomonta.n.u.s knew of the earth's motion around the sun a hundred years before Copernicus; but a German writer has definitely disproved this claim by tracing it to its source in Schoner's _Opusculum Geographic.u.m_ (1553) which states only that he believed in the earth's axial rotation. Ziegler: 62.]

[Footnote 59: Ibid: 62.]

[Footnote 60: Delambre: _Op. cit._: 365.]

Both Janssen,[61] the Catholic historian, and Father Hagen[62] of the Vatican Observatory, together with many other Catholic writers, claim that a hundred years before Copernicus, Cardinal Nicolas Cusa.n.u.s[63]

(c. 1400-1464) had the courage and independence to uphold the theory of the earth's motion and its rotation on its axis. As Father Hagen remarked: ”Had Copernicus been aware of these a.s.sertions he would probably have been encouraged by them to publish his own monumental work.” But the Cardinal stated these views of the earth's motions in a mystical, hypothetical way which seems to justify the marginal heading ”Paradox” (in the edition of 1565).[64] And unfortunately for these writers, the Jesuit father, Riccioli, the official spokesman of that order in the 17th century after Galileo's condemnation, speaking of this paradox, called attention, also, to a pa.s.sage in one of the Cardinal's sermons as indicating that the latter had perhaps ”forgotten himself” in the _De Docta Ignorantia_, or that this paradox ”was repugnant to him, or that he had thought better of it.”[65] The pa.s.sage he referred to is as follows: ”Prayer is more powerful than all created things. Although angels, or some kind of beings, move the spheres, the Sun and the stars; prayer is more powerful than they are, since it impedes motion, as when the prayer of Joshua made the Sun stand still.”[66] This may explain why Copernicus apparently disregarded the Cardinal's paradox, for he made no reference to it in his book; and the statement itself, to judge by the absence of contemporary comment, aroused no interest at the time. But of late years, the Cardinal's position as stated in the _De Docta Ignorantia_ has been repeatedly cited as an instance of the Church's friendly att.i.tude toward scientific thought,[67] to show that Galileo's condemnation was due chiefly to his ”contumacy and disobedience.”

[Footnote 61: Janssen: _Hist. of Ger._, I, 5.]

[Footnote 62: _Cath. Ency._: ”Cusa.n.u.s.”]

[Footnote 63: From Cues near Treves.]