Foundation of Psychology
Chapter 2
The scientific revolution of the seventeenth century and its aftermath

Introduction

The word psychology did not appear in literature before 1500.
Scientific revolution: name given to a series of discoveries in the seventeenth century, involving Galilei, Descartes and Newton, that enhanced the status of science in society.

From a geocentric to a heliocentric model of the universe

The geocentric model of the universe in the sixteenth century

The earth as the centre of the universe

The model that of the universe used in the sixteenth century was the model described by Aristotle who built on others) and elaborated by Ptolemy.
Aristotle’s universe was a limited universe with the Earth in the middle
Geocentric model: model of the universe in which the Earth is at the centre; was dominant until the seventeenth century.

The addition of epicycles

A key problem within the Aristotelian universe was the movements of some of the wandering stars.
To explain strange movements, Ptolemy used the notion of ‘epicycles’.
Epicycles: small cycles made by the wandering stars in addition to their main orbit around the earth.

Copernicus’s alternative heliocentric model

The sun at the centre of the universe

Aristotle’s model was not the only one that had been proposed in ancient cultures.
Heliocentric model: model of the universe in which the sun is at the centre.
Copernicus saw the heliocentric model as a valid alternative for the geocentric model.

Why Copernicus waited to publish his model

Only shortly before his death, Copernicus was persuaded to get his book printed.
Possible reasons

• He was afraid of the reaction of the Roman Catholic church
• Copernicus did not feel the evidence for his model was strong enough to justify publication.

Galilei uses a telescope

Because of the many problems with Copernicus’s model, it failed to have much impact.

Galilei’s observations

Galilei built a telescope and found out that:

• There were many more stars than were visible to the naked eye
• The surface of the moon was not smooth, as claimed by Aristotle, but comprised of mountains and craters.
• Jupiter had four orbiting moons, so that the Earth’s moon was not longer the only heavenly body failing to turn around the centre of the universe.
• The sizes of Mars and Venus appeared to increase and decrease in cycles, suggesting that their distances to the Earth changed over time. In addition, Venus had phases just like the moon.

Response of the Roman Catholic church

On the basis of this evidence Galilei started to argue in letters that Copernicus’s heliocentric model was much more likely than Ptolemy’s geocentric model.
This resulted in an investigation of the church, after which Galilei received a private warning to stop defending Copernicus’s model.
In 1632 Galilei published a book in which one of the characters defended the geocentric model, and the church gave him house arrest for the rest of his life.

Independent of the Church’s reaction, the main outcome of Galilei’s research was that the evidence he presented was so convincing that the heliocentric view rapidly came to dominate astronomy.

Interim summary

• The need for an improved calendar renewed interest in the motions of the Earth, the Moon and the Sun relative to one another.
• The model of the universe that was used was the geocentric model of Aristotle and Ptolemy. This model has the Earth at the centre of the universe.
• Copernicus became interested in an alternative heliocentric model with the Sun at the centre. He did not publish this model until the year of this death, partly because he thought the evidence was not convincing enough and partly because he did not want to upset the Roman Catholic church.
• Nearly a century later Galileo Galilei used a telescope to look at the night sky and observed several phenomena that were easier to explain on the basis of a heliocentric model than on the basis of a geocentric model. In doing so, he upset the Roman Catholic church.
• Because the evidence was so convincing and could be verified by others, the heliocentric model rapidly came to dominate astronomy despite the Roman Catholic church’s resistance.

Mechanisation of the world view

Descartes’ philosophy of man

Dualism

Descartes identified the soul as being divine and independent of everything else.

• Because the human soul was define, human thoughts and feelings could not be studied by the natural sciences and fell under the remit of philosophy and religion.
• Descartes was convinced that the soul had innate knowledge, which could be recovered on the basis of reasoning.

Dualism: view of mind-body relation according to which the mind is immaterial and completely independent of the body; central with religions and also in Descartes’ philosophy.

Mechanistic view of the universe, including the human body

Descartes viewed the universe and all matter in it (including the human body) as one big, sophisticated machine that could be studied by humans.
Mechanistic view: world view according to which everything in the material universe can be understood as a complicated machine; discards the notion that things have goals and intentions as assumed by the animistic view; identified by Descartes.
This was important for the development of science.

Implications for the advancement of science

• The mechanistic view of the world invite scrutiny of workings
• Because of questions about the interactions of the body and soul, the soul got dragged into the mechanical part of the universe and became subject to natural investigations.

Interim summary

• The response of the Roman Catholic church to Galilei encouraged René Descartes to build a new philosophy of man
• In this philosophy a clear distinction was made between the soul, which was define and could not be studied with scientific methods, and the rest of the universe (including the human body), which was a complex machine that could be studied scientifically. This became known as (Cartesian) dualism.
• The mechanistic view of the world came to replace Aristotle’s view, which still contained animistic elements

The formulation of the first laws of physics

Why is the Earth orbiting the sun?

Movements as result of forces

Newton had the insight that objects attract each other.
But, because of differences in mass, the pulling force varies.

In his book Prilosophiae naturalis principia mathematica, Newton described all known movements in the Copernican universe on the basis of three laws and the postulation of a gravitational force.
Each of these components was described in mathematical terms.

Interim summary

• Newton explained why planets orbit the Sun and moons orbit planets
• In doing so, he not only defined the relevant forces, but described them in such detail that they could be calculated precisely
• The resulting mathematical equations were the first laws of physics, published in the Principia mathematica, convincing scholars that science could uncover the mechanisms underlying the universe

What set off the scientific revolution in seventeenth-century Europe?

Factors that contributed to the scientific revolution

Demographic changes

Europe’s population nearly halved in the fourteenth century as result of the Great Famine, the Hundred years war, and the black death.
At the end of the fifteenth century a new growth began.
Around the same time, the feudal system came to an end, which depleted aristocracy.
Cities grew and installed more democratic regimes.

There was an emergence of a large group of merchants that formed a link between the hand workers and the intellectual elite.

Absence of stifling pressure from religion or authority

There were problems in the Catholic church

• Two popes held office simultaneously
• Martin Luther started the Reformation
• Judgment day did not come in the year 1000 or 1033 (thousand years after Jesus’s death)

As a result, the actions of the Roman Catholic church against Galilei were limited in their impact.

The church made a strict distinction between the worldly and the heavenly.
This resulted in two different authorities.

New inventions

• Book printing
  • Made information abundantly available
  • Relieved scholars from the burden of preserving the information from the previous generation
  • Information became available in vernacular, important texts were translated into different languages.
• The mechanical clock
  • Provided philosophers with a working example of a mechanical world
  • Established of a professional group of clock- and watchmakers, who could made the high-precision equipment needed for the scientific experiments that were to come
• The compass, telescope and microscope

The existence of universities and patronage

Universities provided a place for natural philosophers in society and conveyed the message that the pursuit of knowledge about nature was a worthwhile in its own right.
This increased the chances of patronage by wealthy families or even the involvement of those families in the expansion of science.

Massive enrichment from the Greek an Arab civilisations

In the sixteenth century, many more texts became available than those of Plato and Aristotle.

• One of the factors contributing to the increased access to Greek writings was the fall of Constantinople in 1453 and the subsequent flight of Greek scholars to Italy.

Major breakthroughs happen (or can happen) when two main civilisations interact.
This creates a fluidity and dynamism in which new ideas can grow.

Natural philosophy became detached from the big philosophical questions

Gradually, natural philosophers felt allowed to study a phenomenon without prior knowledge about the totality of things (like man’s place in the universe)

Factors that helped the fledgling science grow

• The absence of disaster
• A benevolent religion
• The establishment of learned societies

Interim summary

The following factors are thought to have precipitated the scientific revolution in seventeenth-century Europe

• The growth of the population, urbanisation, and the emergence of a considerable class of merchants
• A crisis in religion
• New inventions that made information more easily available, that led to new questions, and that included the promise of scientific discoveries leading to wealth and power
• The existence of universities and patronage
• Massive enrichment from the Greek and Arab civilisations
• The idea that small issues could be solved without the need of an overall view that explained everything in the universe

The scientific revolution could also have died prematurely if:

• A major disaster or war had happened
• Religion had been able to suppress the new thinking
• Natural philosophers had not been able to organise themselves and create structures that solidified their process

The new method of the natural philosopher

The scientific revolution could not take place unless something fundamental changed in the way scholars approached knowledge-gathering.

Francis Bacon and the importance of the interaction between perception and reason

Traditionally, science was associated with knowledge that depended on reasoning.

The new organon

In 1620 Bacon published a book ‘New organon’, in which he described the new view of science, as opposed to Aristotle’s approach.

• Bacon started by claiming that neither perception nor reasoning alone provides progress.
  Interaction between both is required.
  Weaknesses perception
  • It tends to be biased by people’s convictions
  • People do not observe everything correctly
  • Even when observations are veridical they do not result in useful knowledge unless they are accompanied by reasoning and understanding
• To overcome the deficiencies of observations, Bacon recommended putting them on a firmer basis by tougher coupling between observation and reason

Bacon argued that natural philosophers should experiment to see which changes worked and which not, without bothering about the implications for the totality of the universe.
But, natural philosophers should go beyond the experiments mechanics set up to solve practical problems.
Experimenta frutifera (fruit-bearing experiments): solve practical problems
Experimenta lucifera (light-bringing experiments):determine true causes.
They should additionally use clarifying experiments to determine the true causes of phenomena.

• Ultimately, observations and clarifying experiments must result in deeper understanding.

Natural philosophers must go from particulars (works) to axioms, which in turn will lead to new particulars.
The existence of axioms also allows natural philosophers to purposely search for new phenomena, rather than having to rely on chance findings.

Sometimes an observation or a clarifying experiment may even decide between two alternative explanations. These are crucial instances.

The link between particulars and axioms must be closer than in Aristotle’s view.
To achieve this, Bacon recommend working with a hierarchy of axioms, starting with lesser axioms (close to the observation), going over to middle axioms, to the highest axioms (general and abstract).

Inductive versus deductive reasoning

Deductive reasoning: form of reasoning in which one starts from a number of indisputable premises, from which new, true conclusions can be drawn it the rules of logic are followed.
Because this requires indisputable premises to start with, it usually defends some form of innate knowledge.

Inductive reasoning: form of reasoning in which one starts from observations and tries to reach general conclusions on the basis of convergences in the observations.
This is needed in science to turn observed phenomena into scientific laws, but does not guarantee that the conclusions are true.

Experimental histories to extract the truth from nature

Bacon did not simply argue that deductive knowledge should be replaced by inductive knowledge.
He was well aware of the limitations of perception and inductive reasoning.
Rather, he proposed a much closer coupling between perception and axiom, in which observations are used to formulate and evaluate axioms, and in which axioms were used to guide perception.

Experimental history: method introduced by Bacon in which the natural philosopher extracts the truth from nature by active manipulation and examining the consequences of the intervention.

Are scientific theories always observation-based?

Although Bacon’s writings had a great impact on the development of natural philosophy, to some extent they underestimated the importance of reasoning beyond observation in scientific research.

Knowledge is to be discovered and not to be retrieved from antiquity

In the scientific revolution, there was a growing awareness that a lot of knowledge was still to be discovered.
Gradually, natural philosophers started to realise that the ancient civilisations did not know everything and that some of their knowledge was plainly wrong.

Because of the revision of the past, for a natural philosopher the truth of statements could no longer be based on the authority of history and tradition.

Interim summary

The method of the natural philosopher

• In particular, the writings of Francis Bacon were important in making the new method of the natural philosopher explicit
• Bacon’s advice comprised the following elements
  • Observation and inductive reasoning are much more important in science than acknowledged by Aristotle
  • Systematic observation is important to have a good understanding of the phenomena and to come to correct axioms; it is also important to spot evidence against the prevailing axioms and convictions
  • Because of the limitations of observations, they must be supplemented by experimental histories to extract the truth from nature (rather than passively observe nature); observation and understanding must constantly interact
• Bacon’s view was able to explain quite well the developments that resulted in the scientific revolution, but the emphasis on observation and experimental histories did not explain the ways in which Galilei and Newton sometimes did came to their conclusions
• Another major change was that natural philosophers started to realise that not all knowledge had been known in ancient times and that much still remained to be discovered

Changes in societies as a result of the scientific revolution

The impact of science on daily life

Science and prosperity

Although the practical implications of natural philosophy remained very limited in the first 200 years after Bacon’s writings, by the nineteenth century the new thinking started to alter everyday life.
Industrial revolution: name to refer to the socio-economic and cultural changes in the nineteenth century caused by the invention of machines; involved, among other things, the replacement of the labour of peasants and craftsmen by mass production in factories and the resulting massive relocation from the countryside to the towns.

Science and specialisation

Scientific advances led to a further differentiation of occupations people could hold.
Increasingly they also had to train for these jobs, because these involved specialised knowledge and skills.
This made society more complex and people made use of ‘recipe knowledge’.
Individuals knew how to operate tools but had no idea of their workings.

Proposals to ground society in the natural sciences

The age of enlightenment

The more successful science grew, the more intellectuals in the Western world began to see it as a way not only to gather knowledge, but also organise society.
Age of enlightenment: name given to the Western philosophy and cultural life of the eighteenth century, in which autonomous thinking and observation became advocated as the primary sources of knowledge, rather than reliance on authority.

One of the elements that attracted intellectuals to the natural sciences was the belief that knowledge provided by these disciplines was objective.

Positivism

Positivism: view that authentic knowledge can only be obtained by means of the scientific method; saw religion and philosophy as inferior forms of explanation.

New claims about the status of scientific knowledge

Together wit the assertion that the sciences provided the only valid knowledge, positivists also upped the virtues of the scientific method to their communication to the wider public.

• Because science is based on observation and experimentation, and not on opinion and authority, it is always right
• Scientific theories are summaries of observations and, therefore are always correct
• Because scientific knowledge is always true, it should be the motor of all progress

The counter forces

Not everyone was happy with the rise in status and power of science.

The Roman catholic church

The first institute to challenge science’s ascent was the Roman Catholic church.
The main message conveyed by the Roman Catholic church was not one of science being heretic.

• Clergy presented scientific knowledge as second-rank, detracting individuals from real wisdom, and potentially dangerous if not restrained by religious morals.
• Scientists, like other lay people, lacked the knowledge and the authority to tamper with God’s creation.

In several countries of Europe the strong position of the church in education was part of the struggle between the proponents of enlightenment and the traditionalists.

Protestant churches

Because the new Protestant churches still had to establish their power base, many tended to see science as an ally rather than an adversary.
At the same time, there was little doubt that scientific knowledge dealt with worldly matters and, hence, was the handmaiden of the heavenly wisdom form the scripture and church fathers.
For the Protestants as well scientific knowledge was dangerous if not guided by religion.

Many protestant churches enjoyed good relationships with science.

The relationship between Protestant religion and science deteriorated in the 1870s, when scientists began to react against what they felt to be the patronizing attitude of church authorities.

The humanities

Also outside religion there was a large segment of the population that preferred to keep away from the scientific realm.
Humanities: academic disciplines that continued the traditional study of the ancient classics, increasingly supplemented with teachings of contemporary literature and art.

Romanticism

Romantic movement: movement in the late 1700 to early 1800s that reacted against the mechanistic world view and the emphasis on reason preached by enlightenment. It saw the universe as a changing organism and stressed everything that deviated from rationalism; the individual, the irrational, the imaginative, the emotional, the natural and the transcendental.

The two cultures

There is evidence that the divide between science on the one hand and religion/humanities on the other hand increased in the first half of the twentieth century.

Interim summary

Science has induced many changes in society, such as:

• People became more prosperous and knowledgeable
• A scientific career became a new means of upward social mobility
• Life and knowledge became more differentiated and specialised

The reactions to the scientific revolution can roughly be divided into positive and negative ones

• Positive reactions
  • Reason and science should be the basis of social order (age of enlightenment)
  • Science is the motor of progress and true knowledge (positivism)
  • Scientific knowledge is always true and should guide decisions made
• Negative reactions
  • Roman Catholic church: scientific knowledge is second-rank and dangerous if not guided by religious morals
  • Protestant churches: many saw no inherent contradiction between science and religion, but science still had to be guided by religion (led to attacks by positivists around 1870)
  • Humanities: the traditional world order and education have proven their use; it is dangerous to overhaul it all with rationality and science
  • Romanticists: the mechanistic world view relied on by scientists is wrong; the universe is a living, changing organism

The two cultures

• Snow regretted the gulf that existed between scientists and humanists in the 1950s

Focus on: how revolutionary was the scientific revolution?

Three factors that hindered historians’ awareness of the impact of science on society

• Historians were part of the humanist culture and did not feel much affinity with science
• To historians the accumulation of scientific knowledge seemed like a slow, steady process, spanning over three or even four millennia, without interesting twists and turns
• Many historians questioned whether there was such a thing as scientific ‘progress’. Does history deal with ‘progress?’ And if so, to what end? Are the developments in science steps forward or just steps without directions?

Part of the reason why the notion of scientific revolution has gained currency is that it made the history of science more attractive
Although many aspects of seventeenth-century thought were innovative and ground-breaking, there has been more continuity in human thought than suggested by the word ‘revolution’