Saving the Phenomena? Ptolemeic Astronomy

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En provenance du cours de The University of Edinburgh

Introduction to Philosophy

3335 notes

The University of Edinburgh

Introduction to Philosophy

3335 notes

This course will introduce you to some of the main areas of research in contemporary philosophy. Each module a different philosopher will talk you through some of the most important questions and issues in their area of expertise. We’ll begin by trying to understand what philosophy is – what are its characteristic aims and methods, and how does it differ from other subjects? Then we’ll spend the rest of the course gaining an introductory overview of several different areas of philosophy. Topics you’ll learn about will include: Epistemology, where we’ll consider what our knowledge of the world and ourselves consists in, and how we come to have it; Philosophy of science, where we’ll investigate foundational conceptual issues in scientific research and practice; Philosophy of Mind, where we’ll ask questions about what it means for something to have a mind, and how minds should be understood and explained; Political Philosophy, where we'll investigate whether we have an obligation to obey the law; Moral Philosophy, where we’ll attempt to understand the nature of our moral judgements and reactions – whether they aim at some objective moral truth, or are mere personal or cultural preferences, and; Metaphysics, where we’ll think through some fundamental conceptual questions about free will and the nature of reality. The development of this MOOC has been led by the University of Edinburgh's Eidyn research centre. To accompany 'Introduction to Philosophy', we are pleased to announce a tie-in book from Routledge entitled 'Philosophy for Everyone'. This course companion to the 'Introduction to Philosophy' course was written by the Edinburgh Philosophy team expressly with the needs of MOOC students in mind. 'Philosophy for Everyone' contains clear and user-friendly chapters, chapter summaries, glossary, study questions, suggestions for further reading and guides to online resources. Please click "Start Here" and navigate to the "Optional Reading" page for more information.

À partir de la leçon

Are Scientific Theories True?

(Professor Michela Massimi) In this module we will explore a central and ongoing debate in contemporary philosophy of science: whether or not scientific theories are true. Or better, whether a scientific theory needs to be 'true' to be good at all. The answer to this question comes in two main varieties. Scientific realists believe that theories ought to be true in order to be good. We will analyse their main argument for this claim (which goes under the name of 'no miracles argument'), and some prominent objections to it. Scientific antirealists, on the other hand, defend the view that there is nothing special about 'truth' and that scientific theories and scientific progress can be understood without appeal to it. The aim of this session is to present both views, their main arguments, and prospects.

The Aim of Science: Saving the Phenomena vs. Truth2:29

Saving the Phenomena? Ptolemeic Astronomy5:15

Truth? Galileo and Copernican Astronomy2:05

Scientific Realism and the No Miracles Argument3:31

Scientific Anti-Realism: Constructive Empiricism7:26

Realist Rejoinders: Inference to the Best Explanation5:50

Concluding Summary2:06

Rencontrer les enseignants

Dr. Dave Ward
Lecturer in Philosophy
University of Edinburgh
Professor Duncan Pritchard
Professor of Philosophy
University of Edinburgh
Professor Michela Massimi
Full Professor
Philosophy
Dr. Suilin Lavelle
Lecturer in Philosophy
University of Edinburgh
Dr. Matthew Chrisman
Reader in Philosophy
Philosophy
Dr. Allan Hazlett
Dr. Alasdair Richmond
Dr.
Philosophy
Guy Fletcher
Lecturer
Philosophy
Elinor Mason
Senior Lecturer
Philosophy

Consider astronomy, one of the most ancient scientific discipline known to human

mankind. The observation of stars and planets was

well known already to ancient civilizations (from the Mayan to the Babylonians) as is

recorded by historical records such as astrolabes like this one of Hispano-Moro

origins, and this Japanese hemisphere based on a Korean map of the

fourteenth century. The ancient Greek had developed a very

sophisticated astronomical system with Ptolemy in the second century AD.

In the Ptolemaic system, planets moved along orbital shells.

This was the simplest astronomical hypothesis,

but it required some tweaks to account for some anomalous phenomena.

One of those phenomena well known already to the ancient Greeks was the so called

retrograde motion of the planets — during the course of the year, the

trajectory of any Planets in the blue sky at night appear to form little loops.

Now to explain those loops, Ptolemy assumed that each planet moved along a

small circle called epicycle which in turned moved along a larger circle called

deference. But neither Ptolemy nor Ptolemic

astronomers believed that epicycles and defference were

necessarily a true description of planetary motion.

They were more like mathematical contrivances or sophisticated hypotheses

that could save the appearance, that could save the apparent motions of planets in

the blue sky and night. The French philosopher, Pierre Duhem,

in a short but very illuminating book which was written at the start of the 20th

century, called To Save the Phenomena, reconstructs the history of a physical

theory from Plato to Gallileo. And in that book, Duhem captures very well

the spirit of ancient Greek astronomy as that of saving the phenomena.

So there are lots of quotes from, for instance, Simplicius’s commentary to Aristotle’s

De Caelo that nicely captures this idea, that the aim of science,

the aim of ancient astronomy, was not really to tell us a true story about

planetary motion, but to provide us with a system of hypotheses that could save the

appearances. So interestingly enough, for ancient

Greeks, the aim of astronomy was not to provide a true story

about planetary motion, but just to save the appearances.

Not surprisingly, in 1543, when Copernicus’s book De Revolutionibus Orbium

Coelestium was published, the book came out with a letter to the then Pope.

Paul III, where Copernicus very modestly presented his hypotheses as just

another hypothesis that could save the appearances, although in a kind of more

promising way than the hypotheses of his predecessors.

This is what Copernicus says in, in the quote of Duhem,

“I began myself to consider the movement of the earth.

It seemed an absurd notion. Yet I knew that my predecessor had been

granted the liberty to imagine all sorts of fictive circles to save the celestial

phenomena. I therefore thought that I would be

similarly granted the right to experiment, to try out whether, by assigning a certain

movement to the earth, I might be able to find more solid demonstrations of the

revolutions of the celestial spheres than those left by my predecessors.”

Despite the apologetic tone, Copernicus didn't hide too much his belief that his

heliocentric hypothesis was more certain than any of the fictitious hypotheses of his

predecessors. Yet Copernicus died the very same year in

which his book was published. The book came out with an anonymous

preface which was very carefully crafted by someone called Andreas Osiander.

And the preface somehow mitigated the spirit of Copernicus’s work.

by presenting it as yet another exercise in this well-trodden tradition of saving the

phenomena: “For the astronomer's job consists of the

following: To gather together the history of the

celestial movements by means of painstakingly and skillfully made

observations… and then to think up or construct whatever

hypothesis he pleases such that, on their assumption,

the self-same movement, past and future both can be calculated by

means of the principles of geometry. It is not necessary that these hypotheses

be true. They need not even be likely.

This one thing suffices that the calculations to which they lead agree with

the result of observation.” No wonder the publication of Copernicus’s

book didn't set religious authority aflame, until almost a half century later, when

someone else dared to overthrow this received view of astronomy as just

saving the phenomena and dare to say that the Copernican system

was actually true of the heavens. That person was Galileo Galilei.

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