DEDUCTION
674
DEER
panied the Feast of Tabernacles, during the celebra-
tion of which the dedication of the first temple haii
taken place. During the celebration of the feast
mourning and fasting were not allowed to begin. The
Jews assembled in the temple and synagogues bearing
branches of trees and palms and singing psalms; the
Hallel (Pss. cxiii-cxviii) being sung every day. The
joyful character of the feast was also manifested by
illuminations, which may have been suggested by the
"lighting of the lamps of the candlestick" when the
temple service was first restored (I Mach., iv, 50-51),
or, according to very early Midrashim, by the miracu-
lous burning throughout the first celebration of the
feast of a vial of oil found in the temple. Since the
first century a general illumination of Hebrew houses
has been customary, every house having at least one
light, and some, according to the school of the rabbis,
liaving one light for each person in the house on the
first night and twice the number on each succeeding
night ; others again, having eight lights the first night
and a lesser number each night thereafter. Modern
Hebrews keep the feast on 12 Dec, with strictness, but
do not forbid servile work. At the daily morning
prayer a different portion of Numbers vii is read in
the Synagogue.
LiGHTFOOT, HoT(F HebraictF (Oxford. 1859), s. v.; The Jewish Encydo-pedia, s. v. Hanukkah, the Hebrew name of the feast; ScHuRER, A Hint, of the Jewish People, etc., 2nd ed. of Eng. tr., I, 217, for complete bibliography.
Arthur L. McMahon.
Deduction (Lat. de ducere, to lead, draw out, de- rive from; especially, the function of deriving truth from truth). I. As an argument or reasoning process: that kind of mediate inference by which from truths already known we advance to a knowledge of other truths necessarily implied in the former; the mental product or result of that process. II. As a method: the deductive method, by which we increa.se our knowledge through a series of such inferences.
I. The typical expression of deductive inference is the syllogism. The essential feature of deduction is the necessary character of the connexion between the antecedent or premises and the consequent or conclu- sion. Granted the truth of the antecedent judg- ments, the consequent must follow; and the firmness of our assent to the latter is conditioned by that of our assent to the former. The antecedent contains the ground or reason which is the motive of our assent to the consequent; the latter, therefore, cannot have greater firmness or certainty than the former. This relation of necessary sequence constitutes the formal aspect of deduction. It can be realized most clearly when the argument is expressed symbolically, either in the hypothetical form "If anything (S) is M it is P; but this S is M; therefore this S is P", or in the cate- gorial form, "Whatever (S) is M is P; but this S is M; therefore this S is P". The material aspect of the de- ductive argument is the truth or falsity of the judg- ments which constitute it. If these be certain and evident the deduction is called demonstration, the Aristotelian iirdSei^is. Since the conclusion is neces- sarily implied in the premises, these must contain some abstract, general principle, of which the con- clusion is a special application; otherwise the con- clusion could not be necessarily derived from them; and all mediate inferences must be deductive, at least in this sense, that they involve the recognition of some universal truth and do not proceed directly from particular to particular without the intervention of the universal.
II. When, starting from general principles, we ad- vance by a series of deductive steps to the discovery and proof of new truths, we employ the deductive or synthetic method. But how do we become certain of those principles which form our starting-points? (1) We may accept them on authority — as, for example. Christians accept the deposit of Christian revelation
on Divine authority — and proceed to draw out their
implications by the deductive reasoning which has
shaped and moulded the science of theology. Or (2)
we may apprehend them by intellectual intuition as
self-evident, abstract truths concerning the nature of
thought, of being, of matter, of quantity, number,
etc., and thence proceed to build up the deductive
sciences of logic, metaphysics, mathematics, etc.
Down through the Middle Ages enlightened thought
was fixed almost exclusively on those two groups of
data, both sacred and profane; and that accounts for
the fulne.ss of the scholastic development of deduction.
But (3) besides being and quantity, the universe pre-
sents change, evolution, regular recurrences or repeti-
tion of particular facts, from the careful observation
and analysis of which we may ascend to the discovery
of a third great class of general truths or laws. This
ascent from the particular to the general is called in-
duction, or the inductive or analytic method. Com-
paratively little attention was paid to this method
during the Middle Ages. Apparatus for the accurate
observation and exact measurement of natural phe-
nomena was needed to give the first real impetus to
the cultivation of the physical, natural, or inductive
sciences. In these departments of research the mind
approaches reality from the side of the concrete and
particular and ascends to the abstract and general,
while in deduction it descends from the general to the
particular. But although the mind moves in oppo-
site directions in both methods, nevertheless the
reasoning or inference proper, employed in induction,
is in no sense different from deductive reasoning, for
it too implies and is based on abstract, necessary
truths.
Mercier, Logique (Louvain, 1905); De Wulf, SchoIa.-^lici.sm Old and New (Dublin, London, New York, 19071.
P. Coffey.
Deer, Abbey of, a once famous Scotch monastery. According to the Celtic legend St. Columcille, his dis- ciple Drostan, and others, went from Hy (lona) into Buchan and established an important missionary centre at Deer on the banks of the Ugie on lands given him by the mormaer or chief of the district whose son he had by his prayers freed of a dangerous illness. This happened probably in the last quarter of the sixth century. Columcille soon after continued his missionary journeys and left Drostan as abbot at Deer. Drostan died here about 606. The legend re- ceives confirmation from the fact that the parish of ■ Aberdour venerated St. Drostan as patron. In later years the Normans had little sympathy with the Celtic institutions, so we find the Earl of Buchan in 1219 founding the Cistercian abbey of New Deer about two miles westward of Columcille's foundation, grant- ing to the new abbey a portion of the lands of Old Deer, the rest going to the maintenance of a parochial church. In 1551 the son of the Earl Marischal suc- ceeded his uncle Robert Keith as titular Abbot of Deer holding the abbey lands in commendnm. The flour- ishing monastery soon fell a prey to the Scottish Re- formers. Among its treasures is the venerable docu- ment known as the "Book of Deer". This is one of the oldest monuments of Scottish literature, and was ably edited in 1S69 for the Spalding Club by its secre- tary, Dr. John Stuart. It had become known to scholars in 1858 when it was found in the University of Cambridge. It was then also discovered that the university had come into its possession in 1715 among the books of Dr. John Moore, Bishop of Norwich, which had been purchased by George I and presented by him to the university; how Bishop Moore had ob- tained it is not known. The manuscript is a small, nearly square octavo numbering eighty-six folios of parchment, written on both sides of the leaf in a dark brown ink, in a hand wonderfully clear and legible, The pages had been ruled with a sharp pointed instru-
