(b. Danzig [now Gdansk], Poland, 1571/73; d. Danzig, 25 July 1609)
astronomy, mathematics, methodology.
Keckermann, the son of George and Gertrude Keckermann, was educated by Jacob Fabricius, rector of the Danzig Gymnasium, who imbued him with strict Calvinist doctrine and a detestation of Anabaptists and Catholics. In 1590 he was sent to Wittenberg University, then to Leipzig for a semester (1592), and finally to Heidelberg (1592). In the latter city he obtained his M.A. in 1595, afterward being appointed tutor and then lecturer in philosophy. The chair of Hebrew was conferred on him in 1600. Keckermann’s growing reputation had resulted in an invitation in 1597 from the Danzig senate to return to that city’s Gymnasium. Although he declined this offer, preferring to work toward his doctorate of divinity at Heidelberg (obtained 1602), Keckermann accepted a later invitation and became professor of philosophy at Danzig in 1602. There he remained until he died, “worn out with mere scholastic drudgery,” in 1609.
At the Danzig Gymnasium, Keckermann tried to implement a Ramist reform of the curriculum with a scheme intended to give youths an encyclopedic education within three years. In this new cursus philosophicus the first year was devoted to logic and physics, the second year to mathematics and metaphysics, and the third to ethics, economics, and politics. The key to this syllabus was Keckermann’s systematic method, which was influenced by the view of Petrus Ramus that the correct approach to a discipline is topical and analytical, rather than merely historical or narrative.
Keckermann was not a pure Ramist, however, and was most sympathetic to the progressive Aristotelian views outlined in Jacopo Zabarella’s De methodis. Like Zabarella, Keckermann believed that much of the effort being devoted to the textual analysis of Aristotle (effort that led to the prolonging of the cursus philosophicus) could be better diverted to developing new Aristotelian methods and analytical systems. He thus drew heavily on both Aristotelian and Ramist ideas for his philosophical and logical Praecognita, in which he gave the first theoretical discussion of systems (the set of precepts characterizing each science).
In his lectures at Danzig, he made abundant use of his systematic method. In its published form the typical lecture course is entitled Systema . . . Among the published systeme are treatments of logic, politics, physics, metaphysics, ethics, theology, Hebrew, geography, geometry, astronomy, and optics. These works are philosophical and pedagogical in character and contain little material of any scientific value; certainly there is no scientific originality in them. Their main interest lies perhaps in their illustration of the content of university courses in mathematics and natural philosophy in the early years of the seventeenth century.
Keckermann’s Systema physicum, a set of lectures delivered in 1607 and published in 1610, discussed physics, astronomy, and natural philosophy, all in largely Aristotelian terms. The author differed from most Peripatetics by describing the four elements as less complete and perfect in form than the mixed bodies. Since elements are not completely and individually sui generis, Keckermann found it plausible that they should be capable of rapid transmutation into one another.
The long discussion of comets has a theological flavor, which is not surprising in view of Keckermann’s religious training and devotion. Comets are conventionally defined as terrestrial exhalations produced by action of the planets in the supreme aerial region. God then encourages angels, or permits demons, to join with the comet in producing extraordinary terrestrial effects. God’s unpredictable choice of angels or demons for the task explains the good and bad effects of comets, although some allowance must be made for the comet’s relation to the stars and planets. Predominantly, however, the effects of comets are malign and indicate divine wrath.
There are serious gaps and errors in the Systema physicum. The vacuum is not adequately discussed in terms of Aristotelian motion and place. Keckermann also maintained that water contracts when frozen. This mistake was criticized in 1618 by Isaac Beeckman, who remarked that either a simple experiment or common sense would have exposed the fallacy. Keckermann’s use of experiment—or, rather, of experience—is in fact very crude and imprecise.
The Systema compendiosum totius mathematices (1617) consists of lectures, read in 1605 and other unspecified years, on geometry, optics, astronomy, and geography; it was intended to form the second year of the cursus philosophicus. The geometry section is elementary, although it describes the duplication of the cube and other problems. The main influence of this section—and of the whole Systema—seems to have been Ramus, Scholarum mathematicarum (1569). Among the geometrical authors cited are Regiomontanus, Albrecht Dürer, and Wilhelm Xylander. For the section on optics Keckermann drew on Arab writers, Witelo, and Peter Apian. The astronomical section follows Regiomontanus and Georg Peurbach but also cites Copernicus, Erasmus Reinhold’s Prutenic Tables, and Tycho Brache. Keckermann remarks that while the Ptolemaic theory of the primum mobile is certain, the theory of the planets has defects which compelled Copernicus and Brahe to try to reduce the planetary motions to “greater certainty and superior method” (1621 ed., p. 349). Keckermann disappointingly failed to follow up this interesting statement, although later (p. 357) he cites with approval Copernicus’ criticism (De revolutionibus, III, cap. 13) of the Ptolemaic treatment of the solar year. There is, however, no real examination of the Copernican system.
I. Original Works. The collected ed. of Keckermann’s works is Operum omnium quae extant, 2 vols. (Geneva, 1614), which includes his religious works as well as the Systeme and Praecognita. The Systema physicum septem libris adornatum. . . first appeared at Danzig in 1610. A 3rd ed. was published at Hanau in 1612. The various parts of the Systema mathematices were published separately soon after Keckermann’s death. They were collected into the Systema compendiosum totius mathematices. . . (Hanau, 1617, 1621; Oxford, 1661).
II. Secondary Literatute. The main source for Keckermann’s life is the nearly contemporary biography (1615) by Melchior Adam, Vitae Germanorum philosophorum (3rd ed., Frankfurt, 1706), pp. 232–234. The work of Keckermann is surveyed in Bronislaw Nadolski, Zycie i dzialalność naukowa uczenego gdańskiego Bartlomieja Keckermanna; studium z dziejów Odrodzenia na Pomorzu (Torun, 1961). W. H. van Zuylen, Bartholomäus Keckermann: Sein Leben und Wirken, Tübingen dissertation (Leipzig, 1934), concentrates on the theological works.
For notes on Keckermann’s physics, see Lynn Thorndike, A History of Magic and Experimental Science, 8 vols. (New York, 1923–1958), VII, 375–379. For Keckermann as a systematist, see Otto Ritschl, System und systematische Methode in der Geschichte des wissenschaftlichen Sprachgebrauchs und der philosophischen Methodologie (Bonn, 1906), pp. 26–31; and Neal W. Gilbert, Renaissance Concepts of Method (New York, 1960), pp. 214–220. Beeckman’s criticism appears in Cornelis de Waard, ed., Journal tenu par Isaac Beeckman de 1604 à 1634, I (The Hague, 1939), 215; see also II, 253.
Paul Lawrence Rose