Wednesday, March 04, 2009

John Buridan


John, or Jean Buridan was born in the late 1300s, and studied at the University of Paris under William of Occam. He is typically known as a Scholastic philosopher of the Nominalist school (following his teacher), and you can find here some comments about his philosophy, which led to the term "Buridan's Ass", an analogy I cannot go into now.

(A personal note: I have a copy of his Summa de Dialectica in translation, which I bought because of his "sophismata"; the people at Loome must have wondered what book I was laughing at with such glee... Ahem.)

But - and it will come as a shock - it is as a scientist that we must also consider him.

In what some persist in calling the "Dark Ages", he, NOT NEWTON, is responsible for the idea which is now called "Newton's First Law". He used the Bible, and not an apple, to make the connection which freed the God and the heavens from bondage imposed when the Pagans declared the heavens "divine" and "above" or "beyond" the reach of earthly physics, and when the Mohammedans prohibited God from choosing to erect any Law, natural or moral.

It is an amazing story to tell, how I learned this, how it was first learned, and how it was passed to me. I will give it in a very brief fashion, though it means quoting a lengthy passage from another author...

I was in my father's bookstore, sometime in the late 1980s, when I found a book titled Science and Creation, by Stanley L. Jaki. I read it. In its tenth chapter, "The Sighting of New Horizons" I first heard the names Buridan and Oresme... and Pierre Duhem.

Jaki is a well-known historian of science, author of more than 50 scholarly books, and that book is one of his greatest; but I cannot review it now. Pierre Duhem (1861-1916) was a great thermodynamicist, a hiker, an artist and a Catholic - but he is an even greater historian of science - I shall treat him in a future posting. (Jaki has two biographical works on Duhem, and one on his daughter, who completed the publication of her father's works after he died.)

In Duhem's massive ten-volume study Le système du monde, in his hunt for the predecessors of Newton he examined manuscripts in the library of the Sorbonne in Paris - which eventually led to the works of Buridan.

This discovery is of radical importance. Stunning importance.

You need to read about this in detail, but here I can only give a few choice excerpts. If you wish to learn more, you'll need to order Science and Creation (and the books about Duhem; see here for details.

The classic and most influential case is John Buridan’s Quaestiones super quattuor libris de caelo et mundo which in its slightly modified version due to Albert of Saxony, a disciple of Buridan, had an unmistakable influence on Galileo. Buridan’s work shows that the radical departures from the main proposition of Aristotelian cosmology and physics were made with most direct references to the Christian belief about the fundamental relations between Creator and creatures. Thus, the road from the closed world of Aristotle to the infinite space of classical physics as a framework of unimpeded inertial motion was staked out by Buridan’s emphasis on God’s unrestricted ability to impart rectilinear motion to the whole world, a proposition striking at the very roots of Aristotelian cosmology. Again, one gets an early glimpse of the infinitely numerous worlds of classical physics and astronomy on finding Buridan reaffirm his faith in the power of the Creator in the face of Aristotle’s insistence on the exclusive uniqueness of one single world. The Aristotelian dichotomy between superlunary and sublunary matter was dealt a decisive blow, and the unitary approach of classical physics to earthly and heavenly bodies was foreshadowed, when Buridan, inspired by his faith, discussed the substance of stars in a manner which patently deprived them of the divine and imperishable characteristics which Aristotle attributed to them. While Aristotle denied that the heavens could decay, Buridan was quick to remind his reader that the Creator even has the ability to annihilate the world.

Buridan could not have been more aware of the fact that his highly critical approach toward Aristotle derived from his Christian belief. In discussing the question of the immobility of the uppermost heavens, or the so-called empyreal heavens, Buridan flatly stated that “in many an instance one should not believe Aristotle who made many propositions contrary to the Catholic faith because he wanted to state nothing except what could be derived from considerations based on what is seen and experienced.” Not that Buridan wanted to downgrade the role of reason and experience. He warned lucidly against confusing the respective competence of faith and reason. In discussing the question of whether the plurality of heavenly motions can be directly traced back to God, Buridan offered an explanation that did justice to both theology and natural science. As to the latter he noted that “in natural philosophy one should consider processes and causal relationships as if they always came about in some natural fashion; therefore, God is no less the cause of this world and of its order, than if this world were eternal.”

In making full use of the liberating effect of his belief in the Creator, Buridan produced some insights with a truly modern ring. The classic case was his clear hint at what came to be called the inertial motion of heavenly bodies in classical physics. After reviewing the merits of his impetus theory with respect to various terrestrial motions, he outlined its usefulness for celestial mechanics. Thus, in the same breath, Buridan spoke of broad jump, of planetary motion, and of the Creator who is the ultimate factor imparting given quantities of motion to various parts of the universe:
[the impetus then also explains why] one who wishes to jump a long distance drops back a way in order to run faster, so that by running he might acquire an impetus which would carry him a longer distance in the jump. Whence the person so running and jumping does not feel the air moving him, but [rather] feels the air in front strongly resisting him. Also, since the Bible does not state that appropriate intelligences move the celestial bodies, it could be said that it does not appear necessary to posit intelligences of this kind, because it would be answered that God, when He created the world, moved each of the celestial orbs as He pleased, and in moving them He impressed in them impetuses which moved them without His having to move them any more except by the method of general influence whereby He concurs as a co-agent in all things which take place; “for thus on the seventh day He rested from all work which He had executed by committing to others the actions and the passions in turn.” And these impetuses which He impressed in the celestial bodies were not decreased nor corrupted afterwards, because there was no inclination of the celestial bodies for other movements. Nor was there resistance which would be corruptive or repressive of that impetus. But this I do not say assertively, but [rather tentatively] so that I might seek from the theological masters what they might teach me in these matters as to how these things take place.
Buridan made his last remark with tongue in cheek. He evidently wished to reaffirm the line of demarcation which he carefully observed between a metaphysical and a natural analysis of the phenomena. It was with undeniable originality that he staked out his own field of investigation and he held to it with exemplary consistency throughout a long and most influential teaching career. Contemporaries of Buridan pointed at his novel approach on more than one occasion. They must have sensed that Buridan’s way of thinking signalled a distinct departure from traditional patterns of thought. Later developments showed that Buridan was indeed a pioneering forerunner of Galileo and the earliest major representative of the mechanistic spirit of classical science.
[Jaki, Science and Creation 232 et seq, emphasis added]

I have omitted a number of footnotes; Jaki's books are meticulously documented. Alas, Duhem's Le système du monde has not yet been translated into English (except for some excerpts).

I shall not apologise for the length of that quote, but for its brevity. But - like Gandalf convincing Frodo about the Ring, you need to cast aside any doubt: here in the early 1400s was the Christian birth of science, long antedating Newton. (Not, you understand, that Newton was not Christian - we'll cover that another time. But Jaki points out that Newton "spent precious time in his old age erasing from his notebooks references to Descartes." [Jaki, Patterns or Principles, 76] - more on that another time.)

Much like the destruction of the Ring of Sauron, this utter destruction of the long-held view - the view that the Catholic "Dark Ages" were void of science - has angered many, and made others rejoice. But the evidence is irrefutable, if (like Gandalf) one has the strength of will to follow Duhem and Jaki into some stiff research.

But rather than angering even non-Christians, scientists or not, it ought to be reassuring. It is good to know that modern science was founded in a religion of reason, on the belief that God works rationally - and that the universe is subject to Order. If we didn't believe that - a fact which by no means can ever be proven - we could not do science at all.

Perhaps I ought to have saved Buridan for March 7... but that day is the day I shall do Pierre Duhem. You'll find out why on Saturday.


At 02 April, 2010 23:33, Anonymous Anonymous said...

Thank you for posting this commentary on the scientific work of Jean Buridan. He appears to have been a great thinker and should be considered the Father of Modern Physics. Duhem and Jaki have done a great service in exploring the Catholic Christian roots of modern science. However its unpopularity with the secular establishment keeps it largely hidden.

Too bad so many medieval manuscripts remain unread and untranslated. Historical scholarship has become lazy and our weakened standards of education ensure that ever fewer scholars can actually read the old texts.


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