Life. Gerbert was born in Aquitaine, about the middle of the
tenth century. He became a monk at the monastery of Aurillac, and
there, according to Richer, a contemporary and disciple, he met the
count of Barcelona, with whom he went to Spain in order to study
mathematics and the physical sciences. Thence, at the request of Otho
II, he went to Rome. From Rome he went back to France, and in 991
became archbishop of Rheims. In 997 he was transferred to the see of
Ravenna. In 999 he became pope, taking the name of Sylvester II. He
lived until 1003.
Gerbert is credited with being the first to introduce the Arabic
numerals into Christian Europe.  He is said also to have constructed
clocks and other mechanical contrivances. It was probably his acquaintance with
astronomy and his success as a mechanical inventor that earned for him
the reputation of magician. The legends collected and published by
Benno in the eleventh century represent Gerbert as in league with the
devil. The less ignorant, however, among Gerbert's contemporaries
acknowledged him to be a pious monk and a man of extraordinary
 On the use of Arabic numerals by Boethius, cf. Lavisse Ct
Rambaud, Histoire générale du
IVe siècle à nos jours
(Paris, 1896), Vol. I, p. 785, n.
Sources. Migne, in his Patrologia Latina, Vol. CXXXIX,
publishes the following works of Gerbert: Libellus de Numerorum
Divisione; De Geometria; De Sphaerae Constrictione; and Libellus
de Rationali et Ratione Uti. Gerbert's letters were published by
Masson in 611, and republished by Duchesne in 1636. Richer's
Histories, which throw so much light on the life and character
of Gerbert as well as on some important points of his doctrine, were
first published by Pertz in the Monumenta Germaniae.  To these
sources must be added a poem by Adalbero, published in the
Patrologia Latina, Vol. CXLI, and a letter of Leo, abbot and
papal legate, which is found in Vol. CXXXIX of the Patrologia
Latina. The work De Corpore et Sanguine Domini, attributed
to Gerbert by Pertz and others, is of doubtful authenticity.
 Richer's Histories are published by Migne (juxta
Pertz), Patr. Lat., Vol. CXXXVIII, coIl. 17-170. For
bibliography cf. Potthast, Wegweiser durch die
Geschichtswerke des Europäischen Mittelalters, p. 501.
An excellent monograph of the life and teaching of Gerbert is M.
Picavet's Gerbert, un pape philosophe (Paris, 1897). cf.Catholic University Bulletin, Vol. IV, pp. 295 ff. (July, 1898).
Gerbert as a Teacher. In the midst of the wars and other
external circumstances which combined to bring about a state of almost
universal neglect of learning, Gerbert revived at the school of Rheims
the best traditions of the early days of the Scholastic movement. He
taught the dialectic of Aristotle, using a translation of the
Categoriae in addition to the Isagoge of Porphyry and the
commentaries of Boethius. He also taught rhetoric, employing, it is
said, a mechanical contrivance in order to express the different
combinations of figures of speech, and in one of his letters he speaks
of a sphere by means of which he illustrated "the horizon and the beauties of the heavens."
His work De Divisione Numerorum shows that he occupied himself
with the task of popularizing the theory of multiplication.
Gerbert as a Philosopher. 1. Richer, a contemporary and disciple
of Gerbert, gives a most interesting description of an encounter which
took place at Ravenna in the year 980 between Gerbert, master of the
schools at Rheims, and Otric, the most famous of the masters of the
German schools. The Emperor, Otho II, and many distinguished prelates
lent solemnity to the scene by their presence. Gerbert opened the
discussion by defining philosophy as "divinarum et humanarum rerum
comprehensio veritatis," thus identifying philosophy with knowledge.
Then he proceeded to divide philosophy into theoretical and practical.
He further distinguished physics, mathematics, and theology
(theologia intellectibilis) as parts of theoretical philosophy,
and moral (dispensativa), economic (distributiva), and
political (civilis) philosophy as subdivisions of practical
philosophy. After a discussion as to the place which physiology and
philology should occupy in this classification of philosophical
sciences, the disputants passed on to the question, "What is the aim
of philosophy?" Gerbert answered that the final cause of
philosophical study is a knowledge of things human and divine, in other
words, that philosophy is, so to speak, its own reward. At this point
the argument veered round to the Platonic account of the cause of
the world. Next the disputants took up the discussion of the cause
of shadows, and when, at the close of the day's debate, the Emperor put
an end to the disputation, the question under discussion was whether
mortal is to be subordinate to rational or vice versa,
or, as we should say, whether the term mortal or the term
rational has the greater extension.
2. The Libellus de Rationali et Ratione Uti, addressed to the
Emperor, takes up the problem of predication at the point where
the oral discussion had been interrupted, and inquires whether
ratione uti should be predicated of rationale. It was a
principle admitted by dialecticians that the predicate should possess
wider extension than the subject; since, therefore, reasonable
is of wider extension than using reason, is not Porphyry wrong
when he says that using reason may be predicated of
reasonable? Gerbert approaches the problem by stating the
objections which may be urged from three sources, namely, from the
relation of power to act, from the relation of the
accidental to the substantial, and from the relation of
the higher concept to the lower. He then proceeds to
elucidate these notions, determining the nature of act and power, thus
using the objections in order to throw light on the problem, so that
when he comes to the thesis that ratione uti may be predicated
of rationale he has no difficulty in proving his proposition by
the use of the concepts, act, power, etc., on which the objections
This little treatise is, therefore, the first sample of the use of the
Scholastic method, which, a century later, was employed in
Abelard's Sic et Non, and was perfected by the philosophers of
the thirteenth century. It is by reason of its method rather than of
its contents that the treatise occupies so important a place in the
history of Scholastic philosophy.
3. Adalbero, who was at one time a disciple of Gerbert at
Rheims, and who died in 1030, mentions in a poem addressed to Robert II
of France certain theories concerning the origin of the universe and
adds, "I found these things, being not unmindful of what I have heard."
If the theories in question are those of Gerbert, and it is natural to
suppose that Adalbero is speaking of his former teacher, it is evident
that our philosopher did not confine his philosophical teaching to the
problems of dialectic, but that he carried his inquiries into the
region of cosmogony and anthropology.
4. The letter of Leo, the papal legate appointed to inquire into the
rival claims of Gerbert and Arnoulf to the see of Rheims,
bears further testimony to the many-sidedness of Gerbert's teaching.
It implies that Gerbert included in his curriculum the study of nature
and, perhaps, the study of animal life. This is all the more remarkable
when we recall that Gerbert belonged to an age to which Aristotle's
treatises on the natural sciences were completely unknown.
Historical Position. Gerbert must have exercised considerable
influence on his own generation. The very grotesqueness of the notions
which the superstitious entertained concerning him is proof of his
preeminence. He is in the tenth century what Erigena was in the ninth
and what Abelard will be in the twelfth. His influence, however, was
exercised by his oral teaching rather than by his written works. To his
disciples, and to the masters who succeeded him in the schools in
France, the dialectical movement which was continued by Roscelin,
Abelard, and St. Anselm, and by them transmitted to the thirteenth
century, owes a larger debt than can be accurately determined.