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SCIENCE IN THE MIDDLE AGES · 3362 dagen geleden by Ad van den Ende

Summary of ‘The Mechanization of the World Picture’ from E.J.Dijksterhuis


Adelard of Bath and William of Conches are good examples of twelfth-century science: they have a vivid interest in physical problems and they try to solve them through independent thought and inquiry. But there were enormous difficulties which impeded the growth of science in these times.
These difficulties were due to:
1. the general mental attitude;
2. the current standard of knowledge and technical ability;
3. the intrinsic character of natural science.

Ad 1: People had a great awe for the authority of tradition. This dominated the sphere of natural science as strongly as that of religion. The Greek thinkers had, as it were, been sanctioned by the Church.
This opinion was not shared by Adelard of Bath. From his Arabic teachers he had learned to put reason above authority. The Ancients had gained their authority only by using their own reason.

Ad 2: The low level of mathematical education made the rise of any quantitave physical theory impossible.

Ad 3: The need was not felt to gain insight into the workings of nature and to control the forces of nature.

In the thirteen century the problem of the essence of things superseded that of their behaviour.
In the twelfth century Adelard of Bath and William of Conches make use only of physical, not of metaphysical principles. In their works about the structure of matter they consider the changes in the material world as the result of a modified grouping of small particles.
In giving scientific explanation one should not invoke God’s omnipotence.
“William of Conches (…) warns his readers against involving Scripture in scientific questions: the Bible (…) merely describes in metaphorical language the result of the work of creation.”

“Adelard of Bath calls the celestial bodies living beings, who are the principles and causes of all lower natures.”

Alanus de insulis

Up to now Platonism was the predominant ancient influence in the science of the Middle ages. This found a kind of conclusion in the work of Alanus de insulis (Alain de Lille). Alanus shared with the school of Chartres the boundless reverence for Plato. In his case this was solely based on his acquaintance with a fragment of Plato’s Timaios. He places Nature between God and the world. She forms the human body, to with God imparts the soul. Alanus’ Natura owes its origin to Plato’s World-Soul. The object of research in human science is the activity of Nature. To travel the road through the supermondane one needs the aid of ‘Theologia’ and ‘Fides’. Religion and science do not conflict with one another; they move in two altogether different spheres.

In the twelfth century numbers are principle and obiect for things in the making of things. On them God has modelled things. Numbers interrelate the elements to one another, they move the stars and govern the world. Associated with this was a great appreciation of arithmetic and music.


Through Boethius a part of Aristoteles’ Organon had been accessible. Again thanks to Boethius several of Aristoteles’ philosophical and scientific ideas had found their way to Europe. But his ideas were not yet known in their entirety. And so the fascination of the the totality of his system had not yet made itself felt. In the thirteenth century this system was assimilated and absorbed.That’s why this century is one of the epochs of radical renewal of thought.

It is again to the Arabs that we owe the preservation of Aristotelism and its transmission to the western world. It became known via Spain.
Aristoteles’ comprised all that could be subjected to scientific treatment: nature, philosophy and theology.
Here was what the Christian Church had always sought: a philosophical system which could be made to harmonize with the Christian doctrine.
Up to know it had been possible to interpret the Platonic ideas as thoughts of God. Plato’s World-Soul was the same as the Holy Ghost.
The God of Aristotle was an abstract being, resting in perfect self-sufficiency outside the universe.
The Church identified Aristotle’s authority with its own. Each blow which the discovery of scientific errors delivered to Aristotle’s authority did hit the Church as well.

Thoma Aquinas had a great confidence in the harmony between religion and science. “The works of God reveal His wisdom and power.”

The Aristotelian conception had gained over the Platonic conception: all our knowledge is due to the exprience gained with our senses. There is no inborn knowledge.
Albertus Magnus collected a body of empirical facts for the study of nature, and he did all he could to foster such study.
But Aristotle had underestimated the difficulties in the study of nature. The boundless veneration for him made it extremely difficult to avoid his errors.

Roger Bacon

Bacon opens his main work Opus maius with these impediments to the development of thought:
1. awe of a dubious and consequently unworthy authority;
2. clinging to established tradition;
3. attaching value to popular prejudice;
4. concealment of ignorance under the show of learning.
The weak points in the medieval methods of science were put here in an extremely clear light.
Bacon makes a passionate plea for the application of experiment and mathematic treatment. But there is no evidence that Bacon achieved any real result with his Scientia Experimentalis.This was the result of the prevalent intellectual atmosphere.

Petrus Peregrinus

In 1269 he wrote his Epistula de magnete. On the basis of systematic experiments he describes the fundamental magnetic phenomina: “the distinction between the north and the south pole, the rule for the attraction and repulsion of poles, the magnetization of iron by rubbing it with a magnet, the possibility of breaking a magnetic-needle up into smaller pieces, which appear to be magnets in turn, magnetic induction and the practical application of the magnet as compass-needle.”
Petrus had an intense interest in experimental science.


The fourteenth censury is characterized by a spirit of doubt and criticism. It undermined the edifice of High-Scholastic philosophy. For science it created an atmosphere which was necessry in order to remove the obstacles.

Wiliam of Ockham had this principle: ‘entia non multiplicanda sunt praeter necessitatem’. (entities are not to be multiplied without necessity.) This is called the razor of Ockam. His ‘nominalism’ objected to the philosophical tendency of realism to assign some metaphysical reality to universal concepts. The term conceptualism is more appropriate than nominalism.Nominalism suggests that the universals are no more than names; that’s why ‘conceptualism’ is better. This was not concerned with the question what things really are, but noted that in certain circumstances they are noted by certain names. We do the same: we don’t ask what electricity really is, but use this word whenever certain phenomina occur.

Nicholas of Autrecourt

His views have been diametrically opposed to those of Aristotelian-Thomistiic scientists. Investigators had to apply their minds to things themselves instead of to the study of Aristotle and his commentators.
There is an unbridgeable gap between believing and knowing. The so-called proofs of God’s existence are worthless.
All natural processes consist of local motions of atoms. Light was a flow of particles, emitted by a luminous body.
In 1346 his assertions were condemned as false, erroneus and heretical.

Oresme and his graphical representations
Oresme drew, for the first time, as far as is known, a graph. He represented the velocity of a motion, for any instant of a period, by a linesegment, plotted in a given direction. This rule of Oresme is now usually referred to as the Mertonian rule.


Astronomy enjoyed universal interest in the Middle Ages. From the earliest times cosmology had played a great role in science, philosophy, theology and astrology. From the beginning it had been a part of the quadrivium. From the moment when the Arabs had begun to take an interest in Greek science they had studied astronomy with exceptional care.They had improved it to a considerable extent. Their accurate observations did lead to a greater agreement between theory and observation.

The theory of the motion of the earth

In his Traité du ciel et du monde Oresme explains that the earth performs in one day a complete revolution from west to east. The starry sphere is motionless. The air as well as the water takes part in this rotation.
Oresme’s Traité already contains a good deal of what Copernicus was to repeat two centuries later in his De Revolutionibus Orbium Caelestium.