jump to navigation

Relativity is Absolute May 25, 2009

Posted by Andre Vellino in Philosophy of Science.
trackback

514px-Nikolaus_Kopernikus

The Structure of Scientific Revolutions is perhaps the best known book by Thomas Kuhn. But I think his most interesting book is The Copernican Revolution.  In it Kuhn defends the thesis that Copernicus was more of a Platonist about the importance of circular motion in celestial bodies than Greek astronomers were.

The Greeks also believed that circular motion was the only way to explain celestial motion, but in order to accomodate the additional principle that the earth is at the center of the universe, they had to explain the movement of heavenly bodies in terms of circles moving around circles (epicycles) without worrying too much about whether the physical entities themselves were actually moving incircles.

Copernicus, on the other hand, held the view that the bodies themselves had to be moving in circles.  And if that becomes the core of your theory of the heavens, then explaining the phenomena (e.g. the retrograde motion of mars) is “merely” a matter of  “shifting paradigms”, i.e. setting the sun at the center of the universe and putting the earth in motion. So the core of Khun’s thesis is that Copernicus was more of an “absolutist” about circular motion than ptolemaic astronomers.

Similarly, I would argue that Einstien too was more of an “absolutist” about the laws of nature than his predecessors and that the theory of  “relativity” is a misnomer.  In fact, it is a theory about the “absoluteness” of the laws of nature. Einstien’s insight was that all the laws of nature are the same in all frames of reference. For instance, no matter how fast you are moving, the speed of light is a constant.  And for Einstein there nothing that is exempt from being subject to laws of nature, not even “space” or “time” (which thereby relinquish their role as “absolutes”).

Comments»

1. Terry - May 25, 2009

Hi Andre…. I just had to comment on this post. 🙂 This issue actually caused me a huge amount of confusion as to what “cultural relativism” meant. You see, my introduction to the term “relativity” was through Einstein, for whom the “Principle of relativity”, as you point out, is that the laws of physics are the same for everyone. (Actually, this was first formulated by Galileo ). So, whenever a law seems different in different reference frames, then you’re not looking at it the right way. (Distance in space-time is the same for everyone, so it’s more fundamental than space or time separately).

And so I spent _years_ believing that “cultural relativism” was the search for fundamental underlying aspects that were the same for all cultures.

Oops.

2. Andre Vellino - May 25, 2009

That’s very interesting Terry. You correctly understand “relativity” (in the sense of Einstein and, as you say, Galileo) and completely mis-reads “cultural relativism” to mean invariance to (cultural) frames of reference. There can’t be very many people like you!

3. Daniel Lemire - May 25, 2009

Interesting post Andre.

In a sense, here, it would seem that “absoluteness” is synonymous of “elegance” or “simplicity”.

The difficulty is in knowing what is really important. What is deserving of “absoluteness”. As religious extremists have shown, not everything should warrant your full devotion.

4. Andre Vellino - June 6, 2009

Thanks Daniel (I don’t know why, I missed your comment originally).

For Einstein there were some other “absolutes” like Symmetry – which I suppose you could argue were related to simplicity or elegance. What’s interesting about Symmetry as an unshakable principle about time is that it implies that the “absorption of light” and the “emission of light” are really the same process – take a “movie” of one process, run it backwards and you get the other.

Which, compared to EM field theory makes a huge difference, because it tells you that light has to be “particulate”. In the traditional wave theory of light absorption and emission cannot be symmetric!

What warrants one’s devotion to such principles is whether they have testable empirical consequences. So, if you just hold on to, for example, the principle of conservation of energy and you don’t find nutrinos to explain how energy magically vanished from a nuclear reaction, then at some point you’ll have to give up the principle. But, if you stick to it and predict nutrinos, how much energy they should have, how small they are, how to detect them… and then you find them…. it’s a good reason to stick to your “absolute” (metaphysical) convictions (because they have “borne fruit”, so to speak.)


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: