0:00

Hi, I'm

0:03

Peter

0:05

Adamson

0:07

and

0:09

you're

0:11

listening

0:13

to

0:15

The

0:17

History

0:20

of

0:22

I'm Peter Adamson, and you're listening to the

0:24

History of Philosophy podcast, brought to you

0:26

with the support of the support of at King's

0:29

College London, and the LMU in Munich. College

0:31

London and the LMU in .net.

0:33

online at History episode. dot

0:35

net. error. Trial Error,

0:37

Inquisition. The Inquisition. They say

0:39

that history is They say that history

0:41

is written by the victors and that goes

0:44

double for the history of science. who doctors

0:46

who believed in the four

0:48

and used cupping or to drain

0:50

blood. Biologists who who believed

0:53

in spontaneous generation. cosmologists who

0:55

believed in a pervasive substance

0:57

called called flogiston, anatomists tried

0:59

to divine personality traits based on the

1:01

shape of the head. All are all

1:03

are routinely considered to have been

1:05

backward and ignorant, holding fast to

1:07

theories that had insufficient empirical support. support,

1:10

and stubborn in the face of evidence that would

1:12

have undermined those theories. those theories. The

1:14

verdict is even more severe when it comes

1:16

to those who actively tried to suppress

1:18

ideas ideas turned out to be to be true. No

1:20

No example leaps to mind more

1:22

readily than the Catholic the decision to

1:25

move against to move against Copernicus

1:27

himself came nowhere close to seeing

1:29

his theory condemned, dying some

1:31

decades too early for that. that. So it

1:33

it was left to Galileo Galilei

1:35

to become a martyr for a martyr

1:37

for He was born in

1:40

1564, 21 years after Copernicus' death,

1:42

and and was a fairly old

1:44

man by the time he was

1:46

placed on trial on the by in

1:48

1633. in 1633. A lot lot of time had

1:50

passed between the first proposal of of and

1:52

the and the most dramatic attempt to stamp

1:54

it out. stamp it out. As I've As

1:56

I've mentioned in previous episodes, this this

1:58

was in part because Coperna... because his

2:00

astronomy won relatively few adherents in

2:02

the decades following the publication of

2:05

his path-breaking work on the revolutions.

2:07

It was not just counterintuitive, do

2:09

you feel like the Earth is

2:11

spinning under your feet, but also

2:13

subject to technical objections, like the

2:15

lack of perceived parallax in the

2:17

fixed stars? There were also plausible

2:20

rival models, like that of Tikobrahe,

2:22

and then there was the lure

2:24

of a compromise position suggested already

2:26

by Andreas Asiander. in the preface

2:28

that he added to Copernicus' treatise.

2:30

One could treat kiliocentrism as a

2:32

merely hypothetical construction that is compatible

2:34

with astronomical observations, rather than as

2:37

a claim about the actual physical

2:39

structure of the universe. This is

2:41

exactly what Robert Bellarmine wanted Galileo

2:43

to say. In a letter of

2:45

1615, Bellarmine wrote as follows. There

2:47

is no danger in saying that,

2:49

by assuming the earth moves and

2:52

the sun stands still, One saves

2:54

all the appearances better than by

2:56

postulating eccentric and epicycles, and that

2:58

is sufficient for the mathematician. However,

3:00

it is different to want to

3:02

affirm that in reality, the sun

3:04

is at the center of the

3:07

world and only turns on itself

3:09

without moving from east to west.

3:11

This is a very dangerous thing,

3:13

likely not only to irritate all

3:15

scholastic philosophers and theologians, but also

3:17

to harm the holy faith by

3:19

rendering holy scripture false. Copernicism would

3:21

render holy scripture false. because of

3:24

the biblical passages I mentioned last

3:26

time, such as the one mentioning

3:28

the miracle of the sun's ceasing

3:30

its motion. If there were definitive

3:32

proof that the earth goes around

3:34

the sun, that would be one

3:36

thing, but in the absence of

3:39

such proof it was up to

3:41

the church and its tradition to

3:43

determine the meaning of scripture. It's

3:45

worth emphasizing that it was this

3:47

and not really the motion of

3:49

the earth as such that was

3:51

really at stake for a man

3:54

like Bellarmine. The church's rejection of

3:56

heliocentrism must be understood within the

3:58

context of the counter-reformation. Not because

4:00

that movement was somehow anti-scientific or...

4:02

anti-intellectual. After all, scholastic thinkers of

4:04

the counter-reformation were among the leading

4:06

intellectuals of Europe. Rather, because the

4:08

rise of Protestantism had made it

4:11

vital to insist on the Church's

4:13

unchallenged authority in the interpretation of

4:15

scripture. As so often seeing himself

4:17

as a moderate, Bellarmine was nonetheless

4:19

happy for Galileo and other mathematicians

4:21

to consider Copernicanism as a useful

4:23

hypothesis. So, when Galileo was first

4:26

investigated by the inquisition after a

4:28

complaint, brought by the Dominican, Niccolo

4:30

Lorini, in 1615, Pella mean simply

4:32

instructed him not to defend heliocentrism

4:34

as a proven physical theory. This

4:36

put Galileo in an awkward situation,

4:38

since he was convinced that the

4:41

theory was in fact proven. He

4:43

had at first been attracted by

4:45

heliocentrism without being totally convinced. Thus

4:47

he spoke favorably of the Copernican

4:49

account in a letter to Kepler

4:51

in 1597, but stopped short of

4:53

fully committing himself. Which changed his

4:55

mind was the telescope. After hearing

4:58

reports about the telescope, which had

5:00

been invented in Holland in 1608,

5:02

he built his own instrument and

5:04

then worked on improving its magnifying

5:06

power. Soon he was able to

5:08

see that there are moons orbiting

5:10

around Jupiter, laying to rest the

5:13

notion that all heavenly bodies go

5:15

around the earth. He observed sunspots,

5:17

whose motion across the surface of

5:19

the sun, showed that it too

5:21

is probably revolving. Also visible were

5:23

the phases of Venus. that is

5:25

the incomplete illumination of this planet

5:28

as it orbits the sun and

5:30

is lit up from different angles.

5:32

Mars could be seen to vary

5:34

in apparent size as its distance

5:36

from the earth varied, again in

5:38

keeping with what Copernicus' theory would

5:40

predict. So, quite literally in light

5:42

of Aldus, Galileo was saying by

5:45

1611 that there is certain demonstration

5:47

that the planets go around the

5:49

sun, and by 1615 that Copernicus'

5:51

opinion was certain. When

5:53

he requested that Galileo be investigated, Laurini complained that

5:55

the heliocentrists not only disagree with with readings

5:58

of the Bible, but

6:00

also, but also, Trapple all of

6:02

Aristotle's philosophy, which is so

6:04

useful, it's this to theology.

6:07

theology. Yet Galileo insisted

6:09

that if Aristotle had been shown

6:11

the telescopic observations, he would he would

6:13

have been the first to adopt

6:15

Copernicanism. Following the the dictates of

6:17

empirical observation is a a deeper commitment

6:19

of Aristotelianism than any particular

6:21

idea about the structure of the

6:24

cosmos. the cosmos. Given new new empirical

6:26

findings, it would be against the

6:28

spirit of Aristotle's methodology to continue

6:30

upholding his cosmology. his cosmology.

6:32

of methodology, Galileo rejected out of

6:35

hand the notion that Copernicus' account

6:37

had been put forward only as

6:39

a useful hypothesis. as a useful He

6:41

rightly pronounced pronounced Osyander's be

6:43

an extraneous extraneous one foreign

6:45

one foreign to own thought. own

6:47

thought. In In fact, the whole point

6:49

of On revolutions had been to establish

6:51

heliocentrism as a physical reality. reality.

6:54

Thus Galileo said that Copernicus

6:56

must be wholly condemned or

6:58

left alone. though Galileo

7:00

felt he had Even though Galileo felt

7:02

he had proof on his side, to he

7:04

recognized the need to respond to First,

7:06

there was the First, there was the familiar

7:08

that that if Copernicus were right, then

7:10

things wouldn't fall straight down when dropped

7:12

from a height, but would land far

7:14

away as the Earth rotates underneath. earth rotates Yet

7:17

if we let a stone fall from a

7:19

fall from a a ship's mast, it lands right

7:21

next to the bottom. to the bottom. Not a

7:23

a problem, argued Galileo, if the

7:25

the Earth to to move after being at

7:27

rest, everything might lurch to the side. But

7:29

since the the Earth is already rotating, a

7:32

stone is already rotating along with everything

7:34

else when it is dropped. when it is that

7:36

rotation simply continues as it falls,

7:38

meaning that it moves together with the

7:40

tower or mast. the tower or mast. his

7:42

penchant for rhetorically powerful

7:44

thought experiments experiments, us to

7:46

imagine a to imagine a quickly at

7:48

sea. at sea. In its hold, butterflies

7:50

are fluttering about, and there is a tank

7:52

full of fish. of fish. From the the

7:54

perspective of someone watching them down

7:56

in the the hold, butterflies and fish would seem to

7:58

move just as they do when the boat

8:01

is standing still in port, even

8:03

though they are in fact being

8:05

carried along with the boat. It's

8:07

worth emphasizing here that these really

8:09

are thought experiments, not real ones.

8:11

Though Galileo did depend on empirical

8:13

observation when he used the telescope.

8:15

In this case, he thought that

8:17

one could simply reflect and see

8:19

that the motion of the earth

8:21

would not cause lateral movement of

8:24

the things on the earth. When

8:26

it came to the objection that

8:28

some scriptural passages imply geocentrism... Galileo

8:30

was dismissive. He discusses the issue

8:32

in various writings from around 1615,

8:34

including a letter addressed to the

8:36

Grand Duchess Christina, a member of

8:38

the Medici clan. While he, of

8:40

course, admits that scripture is always

8:42

true, it is often difficult to

8:44

interpret. A tactically astute premise given

8:46

that Catholic theologians, like Bellarmine, were

8:49

insisting against Protestant rivals that the

8:51

Bible does require expert exegesis. Since

8:53

the Bible is aimed at a

8:55

common readership, and concerns itself primarily

8:57

with spiritual and moral matters, we

8:59

can hardly expect that it would

9:01

use precise language when it comes

9:03

to recondite matters of astronomy. On

9:05

such matters, mathematics and physics tell

9:07

us what is true, and we

9:09

must understand scripture in the light

9:11

of these dictates. Galileo is scathing

9:13

about theologians who reach for the

9:16

irresistible and terrible weapon of condemnation

9:18

when they find that they have

9:20

no good arguments on their side.

9:22

They should just keep their noses

9:24

out of the business of astronomy.

9:26

the field in which they have

9:28

no special expertise. They don't even

9:30

realize that deband Copernicanism would mean

9:32

banning astronomy as a whole, since

9:34

with the advent of the telescope,

9:36

anyone who knows what they are

9:38

doing will have to accept Helio's

9:40

centrism. Galileo was not alone in

9:43

this fight. Tomazo Campanel wrote a

9:45

defense of his fellow Italian in

9:47

1622, which suggested that if anything,

9:49

Galileo's manner of philosophizing was more

9:51

compatible with scripture than Aristotilianism. But

9:53

in any case, Galileo should be

9:55

excused, given that he had never

9:57

argued from a theological point. of

9:59

view. Here Campanella echoes the strategy

10:01

used by Camilla Equulani's lawyer. You

10:03

may recall that he used almost

10:05

the same phrase to defend her

10:07

physical inquiries into the causes of

10:10

Noah's flood. Campanella also predicted that

10:12

in the long run it would

10:14

bring the church into disgrace to

10:16

suppress scientific inquiry. This concern does

10:18

seem to have carried some weight

10:20

with the church authorities. When Galileo

10:22

was brought to trial in 1633,

10:24

the inquisitors at first tried to

10:26

work out a kind of plea

10:28

bargain. showing lenience towards an agent

10:30

and celebrated mathematician would help to

10:32

maintain the reputation of their own

10:34

tribunal. Besides, during the initial hearings,

10:37

Galileo triumphantly produced a written record

10:39

of his exchange with Bellarmine from

10:41

almost 20 years earlier, when he

10:43

had simply been warned to teach

10:45

heliocentrism as a fruitful hypothesis and

10:47

not an established fact. This, he

10:49

said, is exactly what he'd been

10:51

doing ever since. He had never

10:53

to his recollection been told not

10:55

to discuss the topic in any

10:57

way whatsoever. Unfortunately for

10:59

all concerned, other figures in the

11:02

Holy Office undermine the plea bargain.

11:04

In a modern study of the

11:06

trial, this has been called a

11:08

miscarriage of justice. The church didn't

11:11

just condemn Galileo for upholding the

11:13

truth, it violated its own legal

11:15

procedures to do so. What moved

11:17

them to employ such underhanded techniques

11:19

against Galileo? Well, Galileo had in

11:22

fact been incautious and provocative, feeling

11:24

relatively secure after being let off

11:26

with that warning from Bellarmine. he

11:28

published his famous dialogue on the

11:31

two chief world systems in 1632,

11:33

a text that makes his sympathy

11:35

for Copernicanism all too evident. The

11:37

sitting Pope, Urban VIII, had been

11:39

an admirer of Galileo, but turned

11:42

against him, perhaps in part because

11:44

he found it useful to have

11:46

an ideological scapegoat in unsettled political

11:48

times. It surely didn't help that

11:51

Galileo allowed the plotting Aristotelian spokesman

11:53

of his dialogue, who bears the

11:55

belittling name simplicio. to repeat an

11:57

argument the Pope himself had raised.

12:00

Urban had had pointed to to Galileo

12:02

an omnipotent God could surely create either

12:04

a heliocentric or geocentric universe universe,

12:06

that one should simply keep

12:08

an open mind. an open mind. We

12:10

must not, he reportedly told

12:12

Galileo, Galileo, power and wisdom. wisdom.

12:14

Unlike God, Galileo had shown Galileo

12:16

had shown rather limited wisdom by putting

12:19

the Pope's argument into the mouth of whose

12:21

very very name indicates that he is

12:24

a simpleton. He perhaps thought he thought

12:26

he was covered by what he said

12:28

about this character in the to the of the dialogue,

12:30

the Aristotelian is in fact

12:32

named after the late ancient

12:34

commentator, commentator, Simplicius. But presumably neither

12:36

anyone else was buying that

12:38

was more than they than they believed

12:41

that his claim that his dialogue treats

12:43

as a hypothesis. only as a

12:45

In fact, In makes a sustained case

12:47

for case for and is not

12:49

shy about not shy how convincing that

12:51

case is. that case is. From the

12:53

modern day vantage point point, though,

12:55

the problematic thing about the the

12:57

is, of course, not its overall

12:59

conclusion, but what Galileo called called

13:01

argument for that conclusion. that conclusion. This

13:04

argument is based on the rise and fall

13:06

of the fall of the tides, the topic to which

13:08

Galileo had also dedicated a separate treatise. treatise.

13:11

His idea is that the tides are caused

13:13

by the double motion of the the Earth, as

13:15

it spins on its axis and orbits the sun.

13:17

He explains how explains how this is

13:19

meant to work with another thought experiment, asking

13:21

us to imagine a moving tank full of

13:23

water, and explaining that the water will oscillate

13:26

along with the motion of the tank. of

13:28

the tank. Of Of course, Galileo was wrong about

13:30

this, and wrong in part because of

13:32

the very point he had made with

13:34

reference to reference to from following and towers. mass

13:36

and The water of the oceans is simply

13:38

carried along with the rest of the with so

13:40

its astronomical motion cannot be the cause of tidal,

13:42

ebb, and flow. cause of tidal ed and flow.

13:45

the error error, Galileo mocked a proposal made by

13:47

others, others, Kepler, according to which the

13:49

tides are caused by the attractive force

13:51

of the of the moon. This is, is, of

13:53

course, perfectly true, though it though it would take

13:55

Newton's theory of gravity to explain the

13:57

phenomenon fully. fully. This

14:00

should perhaps give us pause in

14:02

assessing the epistemological clash between Galileo

14:04

and the church. Though Galileo was

14:06

in the right and had powerful

14:08

empirical arguments on his side, one

14:10

of those arguments was completely wrong.

14:12

Though this is unlikely to make

14:14

us more sympathetic to the inquisitors,

14:16

urban, or even Bellarmine, it might

14:18

make us reflect on the standards

14:20

of proof being invoked on both

14:22

sides. Scholars actually disagree about this

14:24

point. and in particular whether Galileo

14:26

was still wedded to the Aristotelian

14:28

scientific methodology he had encountered at

14:30

the University of Padua. Certainly, Galileo

14:32

did not feel any need to

14:34

follow Aristotle as an authority. In

14:36

one of his most eloquent expressions

14:38

of this independence, he wrote, Aristotle

14:40

was a man, saw with his

14:42

eyes, heard with his ears, and

14:44

reasoned with his brain, I am

14:46

a man, and see with my

14:48

eyes much more than he did.

14:50

As regards reasoning, I believe he

14:52

reasoned about more things than I,

14:54

but whether he reasoned better than

14:56

I about those things which we

14:58

have both examined will be shown

15:00

by our arguments and not by

15:02

our authorities. Yet we've seen already

15:04

that he claimed to be following

15:06

Aristotle's lead by depending on empirical

15:08

evidence. Some interpreters argue that he

15:10

was also trying to employ a

15:12

broadly Aristotelian method of proof and

15:14

to show that his arguments rose

15:16

to the standards for demonstration set

15:18

out in that method. What would

15:20

later be called the scientific method.

15:22

in which a hypothesis is set

15:24

out and then verified by experiment

15:26

would not count as a demonstration

15:28

within Aristotelian logic. Instead, Galileo seems

15:30

to have thought that in some

15:32

cases, empirical observation simply makes something

15:34

immediately evident. This is why an

15:36

experiment can establish a proposition as

15:39

if it had been demonstrated. This

15:41

is what happened when he saw

15:43

the phases of Venus through his

15:45

telescope. He wasn't so much confirming

15:47

the hypothesis that Venus is going

15:49

around the sun. as seeing directly

15:51

that it does. It was in

15:53

this spirit that he pronounced the

15:55

new astronomy to be certain, relative

15:57

to other scientific endeavors that were

15:59

merely probable. For example, astrology. This

16:01

again should give us pause, in

16:03

this case before leaping to identify

16:05

Galileo as a forerunner of the

16:07

scientific and philosophical developments that would

16:09

come with the Enlightenment. As I

16:11

say, he was born in 1564

16:13

and he died in 1642, meaning

16:15

that he lived about half his

16:17

life in the 16th century and

16:19

the other half in the 17th.

16:21

That chronological happenstance underscores his status

16:23

as a transitional figure. Sometimes he

16:25

does seem to belong to the

16:27

17th century, is when he argues

16:29

that bodies and themselves have primary

16:31

qualities like extension and shape, but

16:33

not the sensory features that we

16:35

ascribe to them like taste, odor,

16:37

or color. These are, he says,

16:39

nothing but empty names. If one

16:41

removes the ones sensing them, then

16:43

all these qualities are taken away

16:45

and annihilated. This will become a

16:47

standard distinction in early modern philosophy.

16:49

Yet Galileo can also seem a

16:51

creature of the Renaissance. sounding not

16:53

unlike a Ficino or a telesio,

16:55

when he compares the sun to

16:57

the heart of an animal, suffusing

16:59

as it does the whole cosmos

17:01

with heat, much as the heart

17:03

sends out heat to the animal's

17:05

limbs. This philosophical view, he insists,

17:07

is perhaps one of the principled

17:09

doors by which one may enter

17:11

the contemplation of nature. The lesson

17:13

we should take from Galileo, is

17:15

one we have already learned from

17:17

discussing other scientists working around the

17:19

turn of the 17th century. like

17:21

Senate, Gilbert, and D. Namely that,

17:23

the study of philosophy in the

17:25

Renaissance and Reformation is not just

17:27

the ideal preparation for understanding early

17:29

modern philosophy, it is already part

17:31

of the study of early modern

17:33

philosophy. And that is what we

17:35

are going to start doing in

17:37

earnest in a couple of episodes.

17:39

Back in episode 369, when I

17:41

talked about Galileo's earlier career, I

17:43

promised that I would return to

17:45

him as a way of wrapping

17:48

up coverage of the counterreformation. Having

17:50

made good on that promise, we're

17:52

just about ready to move on

17:54

to the delights of early modern

17:56

European thought, beginning with a... a

17:58

series on philosophy

18:00

in in and 18th

18:02

century the Netherlands. and

18:04

the Netherlands. Yes, we'll be getting

18:06

to to Spinoza and a whole host

18:08

of other famous and not so

18:10

famous names. I know some of you know some

18:12

of you have been waiting for me to get to this

18:14

for years. If so, then I If so, then I thank you

18:16

for your patience for for just a bit more of

18:18

it. Though Galileo was no fan was no fan

18:20

of authority, it I still think it would be

18:22

a good idea to benefit from the expertise

18:24

of an authority on his thought. thought. And and

18:26

that's what we'll do next time time. as we

18:28

bring this current series to a close to

18:30

a talking to talking to Eileen on the history

18:32

of philosophy. of without any

18:34

gaps. any gaps.