Schmitt C.B. (ed.) The Cambridge History of Renaissance Philosophy
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Traditional
natural philosophy
217
colleagues
in
philosophy
at the
Collegio
Romano
to
investigate
the
topic
more thoroughly.
56
Thus,
well
before Galileo's observations
in 1609 of
mountains
on the
moon,
the
ground
had
been prepared
for a
revision
of
medieval
views
on the
material composition
of the
heavens.
57
Such
discussions were
not
without their impact
on
theses relating
to the
four terrestrial elements
and the
qualities
that
characterise them. Medieval
teaching
had
accounted
for
accidental changes
in nature
through Aristotle's
four alterative qualities
(hot,
cold,
wet and dry) and his two
motive qualities
(gravitas and levitas),
explained
in
his
Degeneratione et corruptione and
De
caelo
respectively.
Attempts
to
account
for
fevers
and
other medical phenomena
led
Renaissance physicians
to
make adaptations
in
this doctrine, suggesting,
for
example,
that
coldness might
be the
mere absence
of
heat,
or that there
might
be two
types
of
coldness,
one
real,
as
found
in the
elements,
the
other
privative,
as in
other bodies.
58
Cardano proposed
that
neither coldness
nor
dryness exist
as
such,
but are
merely
the
privation
of
heat
and
wetness
respectively.
59
Telesio thought
of all
four
as
real,
but
maintained
that
wetness
and
dryness
are not
qualities
at
all
—
rather
they
are
substances whose
presence
in a
body make
it
either fluid
or
solid.
60
Scaliger,
on the
other
hand, defended Aristotle's original teaching, arguing
that all
four
are true
qualities, real
and
positive
in the
order
of nature.
61
si verum est, videant Peripatetici, quomodo Aristotelis opinionem de materia caeli defendere
possint. Dicendum enim fortasse erit, caelum non
esse
quintam quandam essentiam, sed mutabile
corpus,
licet minus corruptibile sit, quam corpora haec inferiora.'
56. Menu, Vitelleschi, and Ruggiero all
discuss
the matter. The last presents his conclusions in three
propositions; see Ruggiero 1591, f. 6s
r
: 'Prima propositio. Non
esset
usque adeo improbabile
asserere coelum generabile et corruptibile per mutuam transmutationem cum inferioribus . . .
Secunda
propositio. Multo probabilius est asserere coelum generabile et corruptibile, sed per solam
transmutationem substantialem inter ipsas coeli partes'; f. 6$
v
: 'Tertia propositio. Probabilissimum
tamen est, et probabilius quam superiora, coelum
esse
ingenerabile et incorruptibile, quamquam id
positive demonstrari non potest.' In support of the last proposition,
since
it cannot be
demonstrated, Ruggiero simply argues from the authority of Peripatetics and scholastics in this
matter.
See
also
Benedetti 1585, p. 197. 57. Dales 1980; E.
Grant
1983,
1984b.
58. Galileo
discusses
this question in his early notebooks: see Galilei 1977, pp.
230—4,
dating from
around 1590. Excerpts from the Latin text are given in the following notes.
59. Galilei
1890-1909,1,
p. 160: 'Prima sententia fuit quorumdam antiquorum, apud Plutarchum lib.
De
primo frigido, qui dixerunt frigiditatem
esse
privationem caloris. Horum sententiam secutus
est
Cardanus,
lib. 2
0
De subtilitate, qui idem amrmat etiam de siccitate, quam vult
esse
privationem
humoris.'
60.
Ibid.,
p. 161: 'Tertia sententia est aliorum dicentium, omneshas qualitates
realesesseet
positivas: sed
humorem et siccitatem non
esse
qualitates, sed substantias; idest humorem
esse
substantiam
fluentem; siccitatem vero, substantiam consistentem.' Vitelleschi, in his exposition of this subject-
matter,
attributes this
sententia
to Telesio.
61. Ibid.:
'Quarta sententia, vera, est Aristotelis et omnium Peripateticorum, in t. 8 secundi De
generatione et in 4 Meteororum et alibi, dicentium
omnes
quatuor qualitates
esse
veras, reales, et
positivas: quam sententiam optime tuetur contra Cardanum Scaliger, Exercitationum 18,19, 22, et
Plutarchus.'
Cambridge Histories Online © Cambridge University Press, 2008
218
Natural philosophy
An
analogous discussion took place with regard to the existence of
gravitas
and
levitas
in the elements. The development of Archimedean
teaching on specific gravity and on the role of the medium in hydrostatic
phenomena led Benedetti, for example, to question whether
levitas
is
necessary to account for upward motion, i.e., motion away from the centre
of
the earth, or whether degrees
of
heaviness (equating the light with the less
heavy)
are adequate for this purpose.
62
Galileo wavered on this decision in
his early writings,
then
opted for
gravitas
as offering sufficient explanation,
while
admitting but meagre understanding of its
true
nature.
63
It was in the speculative discussion of local motion, moreover,
that
the
ground was laid for Renaissance advances in the study of dynamics. With
regard to motion, Ockhamists of the fourteenth century had questioned its
reality and its mode of distinction from the object in motion and the
terminus it attains.
64
Related problems concerned the
nature
of place and
the requirement of a medium for local motion; of particular significance
were discussions of the possibility of motion in a void or vacuum, and if
possible, whether motion
there
would be instantaneous or not.
65
The
contrariety and specification of local motions also attracted attention.
Would
the upward and
then
downward motion of a projected stone
constitute two motions or one? The answer could depend on the difference
between a violent motion and a
natural
motion (in the stone's case, upward
and downward respectively), or alternatively, on whether or not a moment
of
rest occurs at the summit or point of reflection. And
then
there
was the
recurrent task
of
tracing moving agents in
natural
motions so as to safeguard
the principle 'whatever is moved, is moved by another'.
66
All of these
questions were argued with increasing intensity in the sixteenth century, as
treatises began to be written on the motion of heavy and light bodies (De
motu
gravium
et
levium)
and experimental evidence began to be introduced
for
their solution, to be described below.
67
Apart from such contributions from the mixed science of mechanics,
others should be mentioned from the sciences of optics and music.
Aristotle's speculative discussion of light and colour pertained to his De
anima and De sensu, but it
was
the
Renaissance revival
ofperspectiva,
coupled
62.
Benedetti
1585; Mechanics 1969, p. 218. 63.
Wallace
1984, pp.
245-8.
64. Cambridge History 1982, pp.
530-6
(Weisheipl);
Wallace
1981a, pp.
341-8.
65. Source Book 1974, pp.
324-60,
554-68;
E. Grant 1981a passim.
66.
Wallace
1984, pp. 162-5, 173-8,
191-202.
67.
Treatises
of
this
kind
were
composed
by
Zimara
(Lohr
1982, p. 251);
Borro
{Dictionary
of
Scientific
Biography
1970-80,
xv, pp. 44-6;
Schmitt
1981, § ix, pp.
267-71);].
Zabarella
(Schmitt
1981 § vm,
pp.
92-106);
Fantoni
(Schmitt
1981, § x); and
Galileo
(Wallace
1984, pp.
230-48),
among
others.
Cambridge Histories Online © Cambridge University Press, 2008
Traditional natural philosophy
219
with
studies
of
the anatomy
of
the eye,
that
led to significant advances in the
understanding of human vision. The medieval contribution had consisted
essentially
of the work of Alhazen and in Avicenna's emendations to
Galenic
doctrine, supplemented by contributions from Roger Bacon,
Pecham
and Witelo. Renaissance
artists
such as Brunelleschi, Alberti,
Ghiberti
and Leonardo worked out theories of linear perspective
that
enabled one to trace the geometrical
paths
of light rays with considerable
accuracy.
68
Ocular anatomists, and among these
Achillini,
Vesalius,
Colombo
and Platter should be mentioned, investigated the eye's
structure
and the respective roles of lens and retina in vision. The findings of both
groups were synthesised by Maurolyco, Delia Porta, Risner and finally
Kepler,
the last developing a full-blown theory
of
the retinal image
that
put
visual
theory on its modern footing.
69
Theory
of music also underwent substantial development during the
sixteenth century.
70
Previous to
that,
Boethius' transmission of Greek
harmonic theory had constituted the main source for a theoretical
understanding of music as a quadrivial science. The invention of new
instruments
and polyphonic scales, together with increasing skill in the
performing arts, led to further studies
of
harmony by Tartaglia and Stevin.
These
finally culminated, in the latter
part
of the century, in a thorough
reworking
of
Pythagorean mathematical harmony by Zarlino.
71
Zarlino's
proposals,
however, were questioned by Benedetti and by Galileo's father,
Vincenzo,
both using physical considerations to correct the purely
mathematical reasoning of the musical theorist.
Vincenzo,
probably with
the help of his son,
then
about twenty-four years of age, even performed
experiments with tuned strings of varied diameter, length and tension to
disprove
Zarlino's polyphonal theory.
72
THE
EMPIRICAL
CONTENT
OF
NATURAL
PHILOSOPHY
The
empirical sciences are usually thought to differ from
natural
philos-
ophy
not only because of their mathematical techniques but also because of
their use of experimentation or controlled observation to establish their
results. As can be seen in the cases of visual and musical theory just men-
tioned, a number of questions discussed in sixteenth-century philosophy
68.
Lindberg
1976, pp.
122-68.
69. Ibid., pp.
172-208.
70.
Palisca
1961;
Walker
1978, pp.
14-33;
Cohen
1984.
71.
Palisca
1956 and his
edition
of Mei
i960;
Drake
1970, pp.
43-52.
72.
Drake
1970, pp.
52-62.
Cambridge Histories Online © Cambridge University Press, 2008
220
Natural philosophy
lent themselves to empirical tests of one kind or another, and it seems
only
natural
that
experimental methods would have evolved out of the
contexts in which they were raised. Some questions,
of
course, such as those
respecting the
nature
of matter or the definition of motion, were too
general to have testable consequences, but others were more specific and
capable of verification in sense experience.
The
study of local motion under the two aspects later known as
kinematics and dynamics turned out to be of pivotal importance for the
development of the science of mechanics.
73
Aristotle's teachings in the
fourth and seventh books of his
Physics
were the point of departure for
much
of
this investigation. In the fourth book, arguing against the atomists'
belief
in a void, Aristotle had proposed a series
of
ratios linking together the
weight
of
a body, the resistance
of
the medium through which it moves and
its velocity of motion, while in the seventh book he had invoked similar
ratios to show how one might formulate rules for comparing motions one
with
another.
74
Commentators were divided over whether Aristotle
himself
thought these ratios and rules were actually verified in
nature
or
whether he employed them dialectically to refute the proposals of his
atomist adversaries.
75
From the fourteenth century onwards, however, the
consensus seemed to be
that
the Stagirite had been serious in entertaining
them, and thus Aristotelians turned to their defence and subsequent
revision.
Much
of the work of Bradwardine and the Oxford
calculators
had been
directed at reformulating the mathematical ratios
that
might lie behind such
rules so as to remove the contradictions
that
appeared to be latent within
them. This and related studies by Heytesbury were carried out in a
theoretical vein in England,
that
is,
secundum
imaginationem
and not with
reference to the works
of
nature.
76
When taken up by Albert
of
Saxony
and
Oresme on the Continent they took on a more practical orientation.
77
At
Paris, for example, the revised ratios were understood as applying not to
imaginary cases but to the actual motions of the heavens and of heavy and
light
bodies.
73. Clagett 1959, P- 163,
justifies
the use of the
modern
division
into
kinematics
and
dynamics
in his
study
of
mechanics
in the
Middle
Ages.
74.
Medieval
attempts
to
justify
and
improve
upon
these
rules
are
discussed
in Crosby 1955, Clagett
1959 and
Oresme
1966.
Representative
excerpts
in
English
translation
are
given
in Source Book
1974, pp.
292-312.
75.
Thomas
Aquinas,
for one, saw
their
use as
merely
dialectical;
see
Thomas
Aquinas
1963b,
p. 240;
also
Weisheipl
1974, pp. 476, 487.
76. Cambridge History 1982, pp.
555-63
(Sylla);
Wilson
i960,
p. 25.
77.
Duhem
1906-13
passim; A.
Maier
1949, pp. 81-154
an<
i
1958, pp.
59-144.
Cambridge Histories Online © Cambridge University Press, 2008
Traditional
natural philosophy
221
In
a
context such
as
this
an
expression used
by
Heytesbury, 'uniformly
difform'
(uniformiter
difformis),
took
on
particular interest.
78
As
said
of an
increase
in
local motion,
the
expression meant
that the
velocity
of the
motion varied,
i.e., that it was
non-uniform
or
difform
and so
accelerated,
but
that the
velocity variation took place
in a
uniform
way
—
another
way of
saying
that it was
uniformly accelerated. Throughout
the
fourteenth
and
fifteenth centuries there
was
prolonged discussion
of how
expressions such
as this might
be
applied
to
different motions, with Gaetano
da
Thiene
playing
a key
role.
It was
only
in the mid
sixteenth century, however,
that
Domingo
de
Soto, teaching
at
Salamanca
and
building
on the
earlier work
at Paris
of
John
Mair, Johannes Dullaert
of
Ghent and
Juan
de
Celaya
(Soto
had studied under
Juan de
Celaya),
proposed
that
heavy bodies accelerate
uniformly
in
their
fall
and
decelerate uniformly when thrown upward.
79
Soto
even supplied numerical examples
that
show
he
understood such
statements
in the
modern sense, though
he
supplied
no
empirical evidence
to substantiate them.
80
It
is
difficult
to
ascertain when assertions
of
this type were first subjected
to actual test.
The
main problem,
it
would appear,
was that of
securing
an
accurate
way
of
measuring short periods
of
time,
of
the order
of
magnitude
of
a
human's pulse beat.
81
Bodies close
to the
earth's surface
can be
seen
to
fall
quickly,
but
variations
in
their velocity
are not
easy
to
detect,
and for
many
it
appeared
that
they
fall
at a
uniform rate.
82
If one
took Aristotle's
ratios
at
face value, however,
not
only would
the
velocity
of
fall
be
uniform,
78.
Heytesbury 1494, ff. 37
r
~40
r
; the edited text is in
Clagett
1959, pp.
238-42.
79.
Wallace
1981a,
pp. 105—7. See Soto 1555, f. 92
vb
, for the text in which he makes this application of
the expression
uniformiter difformis:
'Нес motus
species
proprie accidit naturaliter motis et proiectis.
Ubi
enim
moles
ab alto cadit per medium uniforme, velocius movetur in fine quam in principio.
Proiectorum vero motus remissior est in fine quam in principio; atque adeo primus uniformiter
difformiter intenditur, secundus vero uniformiter difformiter remittitur.'
80.
Thus,
in comparing the motion of two bodies, A and B, the first in uniformly accelerated motion
and the second in uniform motion, he states,
ibid.,
f. 94": 'Exempli gratia, si A mobile una hora
moveatur intendendo semper motum a non gradu usque ad 8 tantumdem spatii transmittet
quantum
B, quod per
simile
spatium eodem tempore uniformiter moveretur ut 4.'
81.
Other problems were associated with the difficulty of comparing the velocities of objects over a
long distance of fall. See Vitelleschi 1589-90, f. 365
v
, in his 1590 commentary on De
caelo:
'Equidem
in hac re experientiam nullam omnino certam habeo, et quas habeo, illae potius obstant
sententiae Aristotelis. Verum multa sunt qui suspectas mihi faciant
omnes
experientias de hac re, in
qua
tamen maxime standum
esset
experientiae. Primum enim vix videtur
posse
fieri ut figura
corporum qui moventur, resistentia medii, et cetera omnia qui ad motum concurrunt
sint
omnino
paria.
Secundo, non potest percipi huiusmodi differentia in velocitate motus
nisi
motus fiat per
magnam
distantiam, ut constat etiam experientia. In magna autem distantia multa accidere possunt
quae experientiae detrahant aliquid certitudinis. Quare cum haec ita se habeant nihil de hac re
statuo, neque enim ad rei materiam
necesse
est in praesentia.'
82. Even Galileo, in his De
motu antiquiora,
thought that acceleration was an initial and temporary
phenomenon, following which a body would fall at uniform speed; see Galilei
i960,
pp. 6—9.
Cambridge Histories Online © Cambridge University Press, 2008
222
Natural philosophy
but
for a
given medium
it
would
be
directly proportional
to the
weight
of
the falling body.
As
early
as 1544
tests were performed
to
show
that the
latter statement cannot
be true.
Details
of
these
are
lacking,
but
their results
were reported
by the
Florentine historian Benedetto Varchi
and attributed
by
him to a
Dominican philosopher
at
Pisa, Francesco Beato,
and to a
Bolognese
physician
and
botanist, Luca Ghini.
83
Benedetti,
in a
work
written
at
Venice
in
February 1554, gave
a
rational disproof
of
the velocity-
proportional-to-weight assertion.
In its
introduction
and
conclusion
he
acknowledges
the
approval
of the
Dominican philosopher
and
theologian
Petrus Arches,
then
visiting
him in
Venice,
who had
discussed
the
proof
with Aristotelians
in
Rome
the
previous summer
and had
convinced them
of
its validity.
84
Since Soto, also
a
Dominican,
was in northern
Italy around
the time
of his
writing
of
falling motion
as
uniformly accelerated,
his
analysis could
thus
have
had
some empirical support.
85
Later,
in 1576, the
Paduan mathematician Giuseppe Moletti brought
additional evidence
to
bear.
He
reported
a
test
(prova)
in
which
a
lead ball
and
a
wooden ball, both
of the
same size, were released from
a
height
and
seen
to
reach
the
ground
at
exactly
the
same time.
86
A
year previously,
one
of
Galileo's teachers
at
Pisa, Girolamo Borro,
had
discussed
an
experiment
(experimentum)
he had
performed repeatedly with pieces
of
wood
and
lead
of
the
same weight projected from
a
high window. Borro found
that the
wood
invariably reached
the
ground
before
the
lead, even though
the
wood's
density
was
much less
than that
of
the lead.
87
It was
this experiment
83. Varchi,
Questioni sull'alchimia,
p. 54, cited by Caverni 1891-1900, iv, p. 270: 'e Aristotile e tutti li
altri
Filosofi, senza mai dubitarne, hanno creduto e affermato che, quanto una cosa sia più grave,
tanto più tosto discende, il che la prova dimostra non
esser
vero. E se io non temessi d'allontanarmi
troppo dalla proposta materia mi distenderei più lungamente in provare questa opinione, della
quale ho trovato alcuni altri, e massimamente il reverendo padre (non men detto Filosofo che buon
Teologo) fra Francesco Beato, metafisico di Pisa, e messer
Luca
Ghini, medico e semplicista
singolarissimo.' On Beato, see Lohr
1974b,
p. 263; on Ghini,
Dictionary
of
Scientific Biography
1970-
80, v, pp.
383-4.
84.
Mechanics
1969, pp.
31—41,
154-65.
85. Soto was present at the Council of
Trent
between 1545 and
1551,
the second date being that of the
first complete edition of his questions on the
Physics,
which includes the statements cited in nn. 80
and 81 above. For details, see Beltràn de Heredia
i960,
pp.
117-205.
86. Caverni 1891—1900, iv, p. 272, quoting a dialogue composed by Moletti: 'anzi vengono tutti in uno
stesso
tempo, e di ciò se n'é fatta la prova, non una volte, ma molte. E v'é di più che una palla di
legno, o più o men grande d'una di piombo, lasciata venir giù d'una
stessa
altezza, nello
stesso
tempo con quella di piombo, discendono e trovano la terra o il suolo nello
stesso
momento di
tempo.'
87. Borro 1575, p. 215, describes the experiment in the following words: 'eadem ergo duo adinventa
aequalis ponderis frustula, ex altiore nostrarum aedium fenestra pari impulsu, eodemque tempore
proiiciemus: plumbum segnius descenderet, super lignum enim, quod prius in terram ceciderat,
omnes quotquot ibi, rei exitum expectabamus, illud praeceps ruere vidimus: idque non semel, sed
saepenumero eodem successu tentavimus.
Cuius rei experimento ducti omnes in eamdem
nobiscum pedibus iuère sententiam.'
Cambridge Histories Online © Cambridge University Press, 2008
Traditional
natural philosophy
223
that
stimulated Galileo
to
perform
his
first tests
(pericula)
with falling bodies,
possibly
from
the
Leaning Tower
of
Pisa,
which
he
reported
in his De
motu
of
about
1590.
8
8
When Galileo actually secured definitive
proof
of
uniform
acceleration
in
free
fall
is
disputed among scholars.
It is
unlikely
that he did
so
much before
1609, and
when
he did he did not
employ time
measurements directly,
but
seems
to
have argued from distances
of
travel
which
he
could measure with considerable accuracy
in an
apparatus
he had
constructed.
89
The
particular chronology
of
discovery
is not too
important
here; what
is
important
is that
such factual questions were being asked
by
the
turn of the
seventeenth century,
and it was
only
a
matter
of
time before
experimental techniques would
be
devised
to
secure answers
to
them.
90
Another
example,
not
unrelated
to the
velocity
of
fall,
is that of the
experimental evidence adduced
in the
sixteenth century
for and
against
the
existence
of
a void
in
nature.
91
Aristotelians differed from anti-Aristotelians
in
the
conclusion they were attempting
to
establish
in
this matter, with
the
Aristotelians
against
the
natural existence
of any
void space, maintaining
that
the
rarefaction
and
condensation
of
continuous matter could explain
all
phenomena
for
which interstitial vacua were being invoked. They
did
allow,
to be
sure,
for the
possibility
of a
vacuum being produced
by
supernatural power,
and
continued
the
late medieval discussion
of
various
thought experiments relating
to
motion
and its
velocity through
a
void.
Those
reacting against Aristotle,
on the
other hand, recovered
the
ancient
writings
of
Lucretius
and
Hero
and
used their ideas
to
develop pro-vacuum
arguments.
92
What
is
remarkable about this dispute
is that
both sets
of
protagonists
invoked
empirical evidence
to
support their respective conclusions,
analysing
phenomena associated with
the
operation
of
bellows,
with water
88.
After
mentioning Borro's result, Galileo states that his test from a high tower shows the opposite:
even though the wood moves faster than the lead at the beginning of the fall, the lead quickly
catches up and reaches the ground long before the wood does. See Galilei 1890—1909, 1, p. 334:
'Experientia
tamen contrarium ostendit: verum enim est, lignum in principio sui motus ocius ferri
plumbo;
attamen paulo post adeo acceleratur motus plumbi, ut lignum post se relinquat et, si ex
alta
turri demittantur, per magnum spatium praecedat: et de hoc saepe periculum feci.' The
English
is given in Galilei
i960,
p. 107.
89.
Apart
from the inclined plane and pendulum experiments described in the Due
nuove scienze,
it is
known that Galileo performed other experiments he never reported but whose vestiges are
preserved in manuscript fragments. These have been analysed and discussed in Drake 1973, Drake
and
MacLachlan
1975, and Naylor 1976, 1980a and 1980b. For a reconstruction of the way in
which their findings may be
seen
to confirm the principle of uniform acceleration in free fall, see
Wallace
1981a,
pp. 150-6, and 1984, pp. 265-8, 323-7, and 343-7.
90. See Schmitt 1981, § vm for a balanced account of attitudes toward experimentation in the study of
motion at the end of the sixteenth century.
91.
Schmitt 1981, §
VII.
92. For a full discussion, see E.
Grant 1981a.
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224
Natural philosophy
freezing
in a closed container, with water clocks and with air withdrawn or
evacuated from a container.
93
In the case
of
the bellows, Toletus argued
that
they could not be opened if their orifice were tightly shut, whereas Patrizi
maintained
that
they could be opened and
that
a vacuum would be
produced by opening them. Both parties believed
that
water contracted
when
frozen, but Soto and Toletus held
that
a closed container, no matter
how
strong, would break
rather
than
permit a vacuum to be formed,
whereas Patrizi and Telesio thought just the opposite.
94
Similar arguments
pro and con the production
of
a vacuum were developed by the same pairs of
thinkers from their understanding of water clocks and the evacuation of
vessels.
95
Unlike the study of falling bodies, however, in these instances no
experiments are known to have been performed and the debate took place
generally
at an a
priori
level.
The most one can detect here is
that
an
empiricist mentality was gradually being formed throughout the sixteenth
century
that
would lead, more or less directly, to the work
of
Torricelli,
von
Guericke
and others in the century to
follow.
Somewhat
surprisingly, those with Aristotelian sympathies were gener-
ally
more empirically minded
than
the proponents of new philosophies of
nature.
96
This can be seen especially in the
life
sciences, with the growth of
botany as a university discipline and the resulting interest in botanical
gardens.
97
Ghini pioneered in this field, first at Bologna and later at Pisa,
and numbered among his students Aldrovandi, Anguillara, Cesalpino and
Maranta. University gardens were established at Padua and Pisa around
1544,
and Aldrovandi built up an impressive natural history museum at
Bologna
in 1570, during which time he had expanded his interest in plants
to include animals and fossils. The anatomical
theatre
dates from this period
also.
98
The importance of accurate observation and realistic portrayal of
human organs led to an emphasis on ocular demonstration
that
produced
exceptional
results, for example, in studying the motion
of
the heart and the
blood.
Vesalius and Fabricius of Aquapendente laid the foundations on
which
Harvey would later base his justly famous, but thoroughly
Aristotelian,
analysis of the blood's circulation.
99
The
less traditional philosophies, however, were not entirely bereft of
93. All of
these
cases
are
analysed
in
Schmitt
1981, § vn.
94. Ibid., pp.
355^9-
95- Ibid., pp. 3
59~62.
96.
This
is
Schmitt's
judgement
when
comparing
Zabarella
with
the
young
Galileo
in
their
studies
of
motion:
ibid., § vm, p. 124.
97.
This
development
is
discussed
in
Schmitt
1984, § xiv, pp.
39-44.
98.
Schmitt
1981, § v, pp.
502-4.
99. See
William
Harvey
1628.
Harvey's
experimental
techniques
and his use of
ocular
demonstration
are
analysed
in
Wallace
1974, pp.
253-67.
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Traditional natural philosophy
22$
empirical content. The programmes on which Paracelsus and his followers
embarked in iatrochemistry, and Delia Porta in natural magic and optics,
led
to important experimental work being done in those fields. The occult
works
of
nature, mainly the influences exerted by magnets and the ebb and
flow
of
the tides, seemed to encourage speculation along more mystical
lines
than
were entertained within the peripatetic tradition. William
Gilbert's
De
magnete
of 1600 is an experimental treatise as good as any in the
century it inaugurated, and even if it was basically Aristotelian in its search
for
the proper causes of magnetic phenomena, it invoked principles
that
were
also at variance with those of the Stagirite.
100
THE
EVOLUTION
OF
SYNTHESES
The
penchant for systématisation in scholastic circles resulted in a number of
syntheses
of
natural philosophy being produced in the Renaissance, some of
which
were read widely and thus had a pronounced influence at the
beginning of the modern period. The earlier of these grew out of
commentaries on Aristotle's
libri
naturales,
to which it became customary to
add
quaestiones
on the more difficult points and to list the various positions
that
had been taken on them, after the fashion of a disputation. As they
evolved
they gradually took the form of a manual useful for teaching,
wherein the author would work out his preferred theses and refute the
teachings
of
opposed schools.
101
In their
fully
developed form they became
part
of a
cursus
philosophicus,
such as
that
of Coimbra at the end of the
sixteenth century, which became a standard text in Jesuit universities. The
syntheses differed from the extensive commentaries on Aristotle produced
by
Pomponazzi, Cremonini and others in
that
they were not directed
exclusively
at understanding the classical text (though such exegesis was
part
of their aim), but incorporated materials from medieval and
Renaissance authors, including those with anti-Aristotelian sympathies, so
as to arrive at a fuller understanding of
truths
about nature.
Before
describing these synthetic treatises, it may be
well
to survey the
commentary tradition
that
preceded them, much of which was strongly
influenced by Averroes, the
Commentator
par excellence, in his extensive
expositions of Aristotle's texts. Two of the foremost Aristotelians of the
early sixteenth century, both of whom taught partly at Padua, were
100. See
Wallace
1974, pp.
241-53.
101.
Some
details
of
this
development
are
given
in
Reif
1969; see
also
Cambridge History 1982, pp. 13-33,
91-8, and
787-96.
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226
Natural philosophy
Pomponazzi
and
Nifo.
Most of the former's lecture notes survive in
manuscript, and these show
that
he lectured repeatedly on the first four
books
of the
Physics,
especially on the first and second books, but also
concentrated on the eighth book. In addition Pomponazzi wrote cursorily
on
the De
caelo,
De generatione et corruptione, Meteorology, and De anima, the
last consistently claiming his attention.
Nifo
left excellent published
commentaries on all
of
Aristotle's
libri
naturales,
explaining not only the text
of
the master but also the exposition
of
Averroes
on the same, and noting as
well
the emendations of other commentators from the Greeks to his
contemporaries. At Bologna,
Achillini
lectured on the first two books of
the
Physics
and the first book of De
anima,
also following the Averroist
tradition; his notes are conserved in the Ambrosiana library in Milan. A
student
of
his,
Boccadifero, published more extensively, leaving commen-
taries on the first book of the
Physics
and on most of the remaining
natural
treatises in printed form.
102
At Ferrara, Antonio Montecatini published an
exhaustive 519-page exposition
of
the eighth book
of
the
Physics,
where the
eternity of the universe is in question, and another detailed analysis of the
first
part
of
the
third
book
of
De
anima,
dealing with the human mind
—
both
of
which posed serious problems for Averroist Aristotelians from the
viewpoint
of Christian doctrine.
103
But the most indefatigable commen-
tator,
again at Padua, was Jacopo Zabarella, who complemented his many
works
on logic with detailed expositions of the first, second and eighth
books
of
the
Physics, the
entire
De generatione et corruptione and Meteorology
and the
three
books of De
anima.
These
commentaries were so prolix
that
many professors thought it
incumbent on them to write briefer treatises summarising the essential
content
of
their teaching. Zabarella
himself
did this in the thirty books
of
his
De
rebus
naturalibus,
published posthumuously in 1590, which encapsulated
the whole
of
his
natural
philosophy. Earlier, Pomponazzi had issued a series
of
Peripatetic treatises defending Averroist positions, to which his
student
Gasparo Contarini replied with an orthodox discourse on the immortality
of
the soul. Another Averroist, Zimara, prepared a series of tables and
compendia comparing and summarising the teachings of Aristotle and
Averroes
to make them more accessible to students.
At
Paris, in the first two decades of the sixteenth century, more
substantial textbooks combining commentaries with 'questionnaires' began
to appear under the influence of Mair and his associates.
104
These are
102.
Lohr
1984. 103.
Lohr
1978, p. 595.
104.
Garcia
Villoslada
1938, pp.
371-421;
Elie
1950-1.
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