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Philosophy week six -Science


This course is making me more and more of a sceptic.

I know really not to believe everything, that I should question, but I believe in the honesty of humanity as a basic premise. This week we have been asking the question

Are scientific theories true?

Dr Michela Massimi of the School of Philosophy, Psychology and Language Sciences of the University of Edinburgh was the lecturer.

My initial response when I saw the question was ‘well no’, they are not true they are theories. Then we test theories we can see if they are true or not. I don’t think that I realised just how much of science that I had taken for granted as a truth was in fact only a theory. I tended not to question the truth of science as it is something I have never fully understood. The men in their lab coats with serious faces tell me something is true and I believe it. Obviously not the ones in washing powder adverts as they are trying to sell me something. Apart from that they can’t all wash whiter than any other.

The first job for me for this course was to put everything into simple English so that I could have a better understanding of the concepts. The lecturer was very clear in her explanations but I am not sure I have it all sorted out I don’t think I yet understand clearly.


Pierre Duhem

The aim of science is either to tell a true story about nature (this is called scientific realism) OR to “save the phenomena” (this is called scientific anti realism. But I didn’t know what “to save the phenomena” meant.

It might not sound like it is very important to know whether science is one thing or another but as this definition has caused most of the great debates in the history of science it is worth at least trying to understand it.

Most of the other lectures were concerned with explaining these two terms.  In order to understand them fully we went back to ancient Greek astronomy and worked our way forward to look at Pierre Duhem’s work. He was a French physicist.

Galileo Galilei and his telescope.

The ancient Greeks in general and Ptolemy specifically had developed theories about astronomy. They mainly involved everything revolving around the earth.

Figure of the heavenly bodies — An illustration of the Ptolemaic geocentric system

This was a very simple hypothesis but it had to be tweaked a little as time went by. It was observed that the planets didn’t actually move in circles around the earth but occasionally did little loops. To save face Ptomely made up a new theory that the planets still rotated around the earth but did little loops at the same time in an epicycle which is a bit like a Spirograph (if you had one of these as a child you will know what I mean.

The basic elements of Ptolemaic astronomy, showing a planet on an epicycle.

This new theory explained the retrograde movements of the planets, the image if you follow the link shows this in motion.

Pierre Duhen wrote his book and called it “Saving The Phenomena”. In this book he explained the theories from Plato to Galilaeo. One of the quotes in the book was Simplicius‘s commentary to Aristotle De Coelo to capture the spirit of ancient Greek astronomy as that of saving appearances by inventing lots of theories about epicycles and deferents based on observations without worrying about what caused things to act the way they did. The aim of the Greeks hadn’t been to tell to truth but to plot the motions of the planets as observed by the naked eye and from that predict the cycles.

Duhen also quoted Copernicus. He theorised that the Sun and not the Earth was the centre of the universe. Dangerous theorising at the time. He dedicated his theory to Pope Paul III thus :-

Taking this as a starting point, I began to consider the mobility of the Earth; and although the idea seemed absurd, yet because I knew that the liberty had been granted to others before me to postulate all sorts of little circles for explaining the phenomena of the stars, I thought I also might easily be permitted to try whether by postulating some motion of the Earth, more reliable conclusions could be reached regarding the revolution of the heavenly bodies, than those of my predecessors.  (Dedication of the Revolutions of the Heavenly Bodies to Pope Paul III)

This apologetic dedication and a carefully worded preface written by Andreas Osiander offers his hypothesis as one among many put forward “to save the phenomena”. Copernicus died the same year his book was published.

Fresco by Giuseppe Bertini depicting Galileo showing the Doge of Venice how to use the telescope

The religious authorities were not very much put out by this publication until much later when Galileo put the cat among the pigeons by claiming it as the truest work on astronomy ever written.  This was after he had observed some new planets than those accepted by the religious authorities and also seen mountains and craters on the moon.

Galileo had created a telescope that could see planets not observable with the naked eye. He said phases in the planet Venus which were impossible under the Ptolomaic system because orbits without ever going behind the sun. He embraced Copernicanism not just as a hypothesis that could save appearances but as a truth that he could observe. He believed this could be reconciled with the Bible as he was a religious man.   His views were not well met and some people even refused to look through the telescope, they disputed the reality of observation.  He wrote ;-

My dear Kepler, I wish that we might laugh at the remarkable stupidity of the common herd. What do you have to say about the principal philosophers of this academy who are filled with the stubbornness of an asp and do not want to look at either the planets, the moon or the telescope, even though I have freely and deliberately offered them the opportunity a thousand times? Truly, just as the asp stops its ears, so do these philosophers shut their eyes to the light of truth.

There followed what is now referred to as “The Galileo Affair”  and his works were forbidden under rules of the inquisition for 85 years.

What matters to us in this story is that Galileo defended the methods of the physicists against the methods of the astronomers. He didn’t think that science should save appearances but that it should tell the truth about nature.

After a period of time modern concepts and technologies have moved on and now the concept of an infinite universe has replaced the concept of a sphere of fixed stars from the ancient Greek astronomy.

Scientific Realism

After an interesting discussion of history and astronomy we came back to the two concepts of the introduction.

Scientific realism is the view that scientific theories aim to give us a true story of the way the world is.  This point is clear for me.  We then progress to the two aspects of the definition semantic and epistemic.

Planets – Wikipedia

The semantic aspect is about the language of science and our understanding of that language. For example if we have a theory about “planets ” then we should know what planets are and all have the same idea about what plants are.

The epistemic aspect has more to do with what we determine a true story is. We should believe that scientific theories are true or and correspond to nature. There is some wiggle room here in that they could be approximately true. Hilary Putnam said the fact that it is true should not be a miracle.

“the positive argument for realism is that it is the only philosophy that does not make the success of science a miracle”.

If we take the theory of gravity on earth  for example, it can be observed every time so we can say that this theory is so successful that if it were not at least approximately  true it would be a miracle.

Anti realism

That brings us right back to the “save the phenomena” theory of anti realism.

This theory argues that scientific theory doesn’t have to be true to be good. Anti realists believe that realism is too narrow and that idealists are too sceptical.

Bas van Fraassen – Princeton.edu

One view of Anti-realism is that of philosopher Bas van Fraassen, “constructive empiricism”.  This view says that whilst the semantic view of  realism is fine the epistemic aspect can’t be so cut and dried.  He didn’t believe that truth was a good measure of how good scientific theories are.

This is the view that how well we construct  scientific models that are adequate to the phenomena is also very important. It is still an empiricist view as knowledge is still derived from experience but what we believe shouldn’t only  come from things that we can see (observable).

If we look at minerals for example there are things that we know about them by conducting physical experiments. We can determine their melting point and how they combine.  Other factors are unobservable such as the atomic number or the number of protons. We can do this by constructing models of the minerals.  We can’t observe an atomic number with the naked eye or the molecular structure but we can build models of them either with ball and stick geometric structures or with computer simulations. These models are meant to be adequate to explain the phenomena of how minerals are put together. They are useful tools but they do not deliver any truths about things we can’t see.

Ball and stick structure.

If we look at minerals for example there are things that we know about them by conducting physical experiments. We can determine their melting point and how they combine.  Other factors are unobservable such as the atomic number or the number of protons. We can do this by constructing models of the minerals.  We can’t observe an atomic number with the naked eye or the molecular structure but we can build models of them either with ball and stick geometric structures or with computer simulations. These models are meant to be adequate to explain the phenomena of how minerals are put together. They are useful tools but they do not deliver any truths about things we can’t see. The atoms here are idealised as perfectly spherical balls of different colour, they are not a true image.

The scientific model is good if it tells us enough about the phenomena to be considered useful. It saves the phenomena. It isn’t quite the same as the ancient Greek astronomers view. They had to make sure that science didn’t conflict with ‘divine knowledge’. Modern scientists are not under this restriction.

The success of science can be explained by empirical adequacy and not in terms of truth. Calling a theory true is too high risk. Today’s DNA and electrons may become the aether and caloric of the future.

A theory is empirically adequate if what it says about the observable things and events in the world is true – i.e., if it saves the phenomena.

Van Fraassen’s Darwinian response to the “No Miracles argument” was that theories are naturally selected in such a way
that those with false observational consequences are discarded, and the survival adaptive ones are those that “fit the observable phenomena”. The success of science is not miraculous and can be explained in terms of empirical adequacy,
not in terms of truth with respect to unobservable entities! Why should we not trust a microscope to deliver a reliable image of the unobservable?

Inference to the Best Explanation

Two “realist” arguments  against van Fraassen’s constructive empiricism are:

I. Van Fraassen’s Darwinian response to the “No Miracles argument” does not cut any ice. It’s one thing to explain why only successful theories survive; but quite another  to explain why a theory is successful in the first instance. Only realism can explain the later.

II. Why suspend belief about unobservable entities (be they atoms, electrons, or DNA)?

Philip Kitcher’s and Peter Lipton’s reply to this question is  the inferential path that leads to unobservable entities is one and the same with the inferential path that leads to unobserved observables (e.g. extinct species like trilobites and dinosaurs), namely Inference to the Best Explanation. 

We infer the hypothesis, which, if true, would provide the best explanation for the available evidence.

Higgs boson – Wikipedia

From fossil evidence palaeontologists have reconstructed some important information about now extinct species like trilobites and dinosaurs.  Similarly we can explain that the Large Hadron Collider can provide evidence for an exclusive particle like the Higgs boson. 


As usual my conclusion is what, after my research and the lectures I have come to understand.

I understand that some people think that scientific theories have to tell us the truth about the world or at least have enough basis in fact to approximate the truth. Others believe that scientific theories can still be good even if they are not true as long as the models that we base the theory upon is adequate to the phenomena. Both camps believe that the words we use have to be recognisable and understood as the same thing by everyone.



  1. Nat Nelson says:

    I am still struggling with this course but your posts help. I might start reading these posts before I look at the videos. Thank you.

    • Louise Taylor says:

      The lectures don’t actually take me that long to watch. What takes all my time is trying to put what I can read and hear into a language that I understand. That is all I am trying to do with these blog posts, explain it to myself. I’m glad it helps you too Nat, I just hope I have it right. I don;t feel able to join in the forum discussions as I don’t understand what they are talking about most of the time. A lot of them see to try to use the most complicated language they can – posturing maybe.
      Good luck.

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