PCF Philosophy of Science Library

[Marshall]

I see some possibility of having interesting discussion threads here Joint S&P. It's not something I know a great deal about. (Not a philosophy buff, or even a philosophy of physics buff). I'd like to gather a bunch of links to experiments that may raise conceptual issues. Since I'm not an expert in this line I will do so inexpertly---make a stab at it---and welcome helpful contributions from others.

My view is that the progress of physics can get stuck because of problems with unexamined concepts. Habitual concepts may block progress and need re-understanding. So I'd like links to a grabbag of experiments (and theoretical results as well) that seem to probe and highlight conceptual puzzles.

Also general source material like Wiki articles are OK.

It seems that the 1935 EPR paper triggered a huge amount of experimentation which is still going on after more than 70 years. Showing violation of local realism.
http://www.physorg.com/news155382024.html
March 4th, 2009 "It's Easier to Observe the Failure of Local Realism than Previously Thought"
http://www.physorg.com/news132830327.html
June 16th, 2008 "World's Largest Quantum Bell Test Spans Three Swiss Towns"
EPR refers to the 1935 paper of Einstein Podolsky Rosen.
Background in wiki:
http://en.wikipedia.org/wiki/Bell_test_experiments
http://en.wikipedia.org/wiki/EPR_paradox
http://en.wikipedia.org/wiki/Bell%27s_theorem
Related news I don't have time to evaluate right now:
March 4th, 2009 http://www.physorg.com/news155386974.html
January 14th, 2009 http://www.physorg.com/news151164690.html

The idea that something real and definite underlies what we measure. And idea that spatially separated things can't communicate faster than the speed of light. May have to give up one or the other or both. Presumably they'll keep locality and give up realism, just my guess. Or some more bizarre outcome.

Now about the idea of Time. Rovelli has an essay called "Forget Time" that recently won a FQXi award. Says time is not a fundamental feature of reality. More like temperature. The concept of temperature only emerges macroscopically/statistically when you have a large number of things. If you look closely at a microscopic level temperature (as we are used to thinking of it) does not exist. Not fundamental IOW. Emergent.
The other FQXi first prize winner, Julian Barbour, says the same thing. Time not fundamental. Shows it by elemetary classical analysis.
So the concept of Time is being challenged. Here are links:
Rovelli
http://arxiv.org/abs/0903.3832
Barbour
http://arxiv.org/abs/0903.3489
Both essays wrestle at a philo level with the concept of time. Both are by world-class experts. It's a good introduction to the problem IMHO, if anyone is looking for one. Ordinary quantum mechanics takes a classical time for granted. The time variable is different from all the others, it is not a quantum observable but is outside the system studied and purely classic. So there is a deep-rooted difficulty in physics waiting to be resolved.

About the idea of spatial dimension. Usually dimensionality, either of space or spacetime, is taken for granted. Space is set up with some dimension, assumed to be an integer, and assumed to be constant independent of place, time, and the scale of measurement.
However in mathematically defined spaces such as fractals, dimensionality can have non-integer values, can vary from place to place, and can vary with scale.

Of course the real spacetime we live in could be like that---hasn't been ruled out. A number of groups working on this, deriving consequences. Some observational consequences have been proposed. Working towards potentially testable predictions. Here are links to recent work.
http://arxiv.org/abs/0812.2214
http://arxiv.org/abs/0811.1396
http://arxiv.org/abs/hep-th/0505154
http://arxiv.org/abs/hep-th/0505113
http://arxiv.org/abs/hep-th/0508202
An easy introduction is in a recent Scientific American article
http://www.signallake.com/innovation/SelfOrganizingQuantumJul08.pdf
Physorg also had something recently:
http://www.physorg.com/news157203574.html
March 25th, 2009 "Spacetime May Have Fractal Properties on a Quantum Scale"

This listing is preliminary and slap-dash. Maybe we can improve it. Something to go on anyway. Concepts like locality, realism, time, dimensionality can yield seemingly paradoxical expectations, may need to be re-examined at a philosophical level, re-conceived.

[Marshall]

Have to share this quote with you. Claus Kiefer is a worldclass expert on GR, gravitation, quantum gravity. Here is how he began his FQXi essay
http://www.fqxi.org/data/essay-contest- ... er_fqx.pdf

"On December 14, 1922, Albert Einstein delivered a speech to students and faculty members of Kyoto University in which he summarized how he created his theories of relativity [1]. As for the key idea in finding special relativity in 1905, he emphasized: 'An analysis of the concept of time was my solution.' He was then able to complete his theory within five weeks.

An analysis of the concept of time may also be the key for the construction of a quantum theory of gravity. Such a hope is supported by the fact
that a change of the fundamental equations in physics is often accompanied by a change in the notion of time. Let me briefly review the history of time in physics."

It's not a bad essay either! Kiefer got the second juried prize in the FQXi context. I'll copy the title and abstract:

DOES TIME EXIST IN QUANTUM GRAVITY?
Claus Kiefer
Institute for Theoretical Physics, University of Cologne,

Abstract
"Time is absolute in standard quantum theory and dynamical in general relativity. The combination of both theories into a theory of quantum gravity leads therefore to a “problem of time”. In my essay I shall investigate those consequences for the concept of time that may be drawn without a detailed knowledge of quantum gravity.

The only assumptions are the experimentally supported universality of the linear structure of quantum theory and the recovery of general
relativity in the classical limit. Among the consequences are the fundamental timelessness of quantum gravity, the approximate nature of a semiclassical time, and the correlation of entropy with the size of the Universe."

Schmungles, I think the Einstein quote in Kiefer's paper (he gives the original source reference) is kind of a smoking gun for the involvement of philosophical investigation at key junctions in the history of physics. Einstein says how he got Special Rel was he began with an analysis of the concept. He was willing to assume he didnt know what time was and re-examine and re-invent the concept. Philo of Physics is basically the systematic examination of the concepts that are taken for granted, and sometimes progress depends on doing that.

I think Newton re-invented the idea of space (and possibly also time) when it was his turn. Newton's space is different from that of Aristotle or of Leibniz. He argues a lot about it and even invokes the Deity. He had to struggle to establish his idea of space. But then it worked so well that it was a shoo-in and ruled physics for some 3 centuries. Rovelli reviews the history of these philosophical interventions in physics, at key junctions.
His book is called Quantum Gravity. Ask me if you want a page reference.

Anyway, I think to understand the present fix that physics is in it can help to look at some of the puzzles that have arisen around the fundamental ideas. Especially, in my view, where there is an experimental angle to it. My bias is away from pure theory and more towards the pragmatic empirical approach. So I am especially interested in observational testing.

If you have some puzzles and conundrums to add to the grab-bag. Please do :-)

[xcthulhu]

So I thought I'd mention a few topics of interest:

A staple problem of philosophy of statistics is the lottery paradox:
http://en.wikipedia.org/wiki/Lottery_paradox

(A little plug - the philosopher who came up with this problem, the late Henry Kyburg, is the logician who convinced me to get a BA in Philosophy)

Another interesting problem, especially for statisticians who cannot rely on very heavily on the law of large numbers is Simpson's paradox:
http://en.wikipedia.org/wiki/Simpsons_paradox
http://plato.stanford.edu/entries/paradox-simpson/

My favorite answer to this problem that I've read so far is due to the computer scientist/philosopher Judae Pearl:
http://bayes.cs.ucla.edu/R264.pdf

Pearl's solution is connected to the mathematician Leonard J. Savage's Sure Thing Principle, which first appeared in his book The Foundation's of Statistics (which is kind of hard but totally brilliant!). For those interested, Nobel Laureate Robert Aumann has a paper on this idea here:
http://www.ma.huji.ac.il/~raumann/pdf/dp393.pdf

It should be noted that people defy the sure thing principle all the time in lab experiments in behavioral economics. Here is a program on this:
http://amos.indiana.edu/library/scripts/sure-thing.html

[Marshall]

A new essay by Max Tegmark has appeared, on the MWI.
The MWI is old, and one might suspect it has been discussed enough. But Tegmark is a young bright entertaining writer. So you might have fun with this:

http://arxiv.org/pdf/0905.2182v1

He illustrates it with some cartoons. Actually I meant to put a link to the abstract, so you can see the summary without having to download. :-D
http://arxiv.org/abs/0905.2182v1

There is a book in preparation (to be published by Oxford U.P.) that deals with the MWI. This is Tegmark's contribution--- to be one of the chapters of the the book.

Personally the MWI has never appealed to me, but I know it might interest other folks, so I'm flagging this new article just in case.

[Giacomo]

Tonight on PBS you can watch the Many Worlds theory

http://www.pbs.org/wgbh/nova/manyworlds/byrne.html

[xcthulhu]

Experimental Philosophy
--------------------------

Experimental philosophy is a relatively recent movement in analytical philosophy; to date the movement appears to be composed entirely of philosophy professionals. In experimental philosophy, researchers take into consideration survey responses when analyzing philosophical problems. One main topic appears to be the notion of intention in ethics. The majority of this work has been done by a leading researcher, Joshua Knobe:

Intention, Intentional Action and Moral Considerations by Joshua Knobe
http://analysis.oxfordjournals.org/cgi/ ... t/64/2/181
doi:10.1093/analys/64.2.181
[Note: I do not have access to this paper - I would be greatful if someone could send this to me!]

Intentional action in folk psychology: An experimental investigation by Joshua Knobe
doi:10.1080/09515080307771
http://www.unc.edu/~knobe/Side-Effect.pdf

Acting Intentionally and the Side-Effect Effect by Leslie, Knobe and Cohen
http://ares.sjsu.edu/upload/course/cour ... effect.pdf

To be honest, I am not terribly interested in analysis of moral intuitions, so I admit to only having briefly skimmed these papers. They all involve survey analysis of questions asked to audiences involving morality and intention.

Another main topic seems to be cultural relativity of philosophical intuition. There are two main papers:

Normativity and Epistemic Intuitions by Weinberg et al:
http://www.rci.rutgers.edu/~stich/Publi ... itions.pdf

Semantics, Cross-Cultural Style by Machery et al:
http://www.rci.rutgers.edu/~stich/Publi ... itions.pdf

Here are synopses of these two papers:

The first paper paper addresses matters of epistemology, or the study of knowledge. In this paper, participants were asked to analyze a series of thought experiments including so called Gettier problems, which are considered challenging puzzles by epistemologists.

The second paper addresses matters of reference typically analyzed in modern metaphysics literature, and draws on thought experiments in Saul Kripke's Naming and Necessity, which is required graduate reading in philosophy in many universities.

In both papers, the authors follow the work of Richard Nisbett, a cognitive psychologist who has done work establishing cultural difference in cognition between westerners and east asian participants. In both of the above cases, the authors report cultural difference in topics thought to be governed by philosophical intuition (generally considered to be invariant to cultural consideration).

Reponses:

One response to this work is by Marica Bernstein, a biologist at University of Cincinnati. Her paper focuses mainly on methodological problems she sees with experiment design and practice among experimental philosophers. She expresses enthusiasm for the project, but expresses that rigor and attention to important details of experimental are lacking in many experimental philosophy publications:
https://oncourse.iu.edu/access/content/ ... design.pdf

Other responses are primarily rationalistic. Antti Kauppinen discredits the philosophical relevance of the above papers as he outlines:

The point of departure for my critique of experimentalism is that the proponents of this type of experimental philosophy, whether pessimistic or optimistic, ignore the fact that typical philosophical claims of what people would say are elliptical. I identify three characteristic assumptions that philosophers implicitly make about the responses that count as revealing folk concepts – competence of the speaker, absence of performance errors, and basis in semantic rather than pragmatic considerations. I argue that in virtue of these assumptions, intuition statements cannot be interpreted as straightforward predictions, and therefore cannot, for reasons of principle, be tested through the methods of non-participatory social science, without taking a stance on the concepts involved and engaging in dialogue.

He instead suggests expert analysis by professional philosophers as a superior alternative form of analysis (which is considered traditional in academic philosophy):
http://www.helsinki.fi/%7Eamkauppi/phil ... osophy.pdf

Finally, experimental philosophy has enjoyed positive press reviews:
Philosophy's Great Experiment in Prospect Magazine:
http://www.prospect-magazine.co.uk/arti ... p?id=10638
What Is Experimental Philosophy? by Joshua Knobe in The Philosopher's Magazine
http://www.unc.edu/~knobe/ExperimentalPhilosophy.pdf

More publicity may be found on Joshua Knobe's website, as well as critiques and overview papers:
http://www.unc.edu/~knobe/ExperimentalPhilosophy.html

[Forest_Dump]

I happened to be checking out the local university bookstore and chanced upon a new one that, of course, I could have mentioned in any number of strings but thought that, overall, this might be the best one. It is proving to be an interesting late summer read while sitting outside on a nice summer afternoon.

Jonathan Marks (2009) "Why I am Not a Scientist: Anthropology and Modern Knowledge." University of California Press.

The author is actually a professor who teaches mostly biological anthropology, specifically mostly genetics and human evolution, etc. The title is meant to be somehwat provocative, of course, and in the preface he actually immediately points out that it is not really true and he can no more be a non-scientist than Bertrand Russell could "define himself out of Christianity". This one looks at science from a cultural anthropological perspective, much along lines of thought I have been playing with for a number of years. Well worth the read.

[Forest_Dump]

And another one. Over the holidays I decided to read:

Bowler, P. J. (2007) "Monkey Trials and Gorilla Sermons: Evolution and Christianity from Darwin to Intelligent Design." Harvard University Press.

In short the author looks at the history, before and after Darwin, of how the concept of evolution and the theoretical explanations of it, were accepted and debated. There are many aspects of this topic I had only dimly considered from why many members of the religious communities of the time accepted evolution (the rationalisation for progress) and why some members of the scientific community, including Lyell and Huxley, were not that crazy about Darwin's ideas. Among other things, it made me want to go back and read up a bit more (again) on Herbert Spencer. Well worth a read.