Tuesday, January 26, 2010

Justifying Metaphysics to its Critics

There has been a (to me gratifying) rebirth of metaphysics in English-speaking philosophy over the last couple of decades. Now, just as in the past, there is a backlash coming from within the profession. One locus of the opposition comes from philosophers of science. Now one of the best contemporary philosophers of science, Craig Callender, has a draft paper (“Philosophy of Science and Metaphysics”) giving his own critical assessment of metaphysics, which he presents in a judicious and thoughtful manner. (For a recent bloggy example of the tension here, see the sometimes pointed debate down in the comments to this post at It’s Only A Theory.)

Callender believes metaphysics plays an important role in science itself as well as philosophy of science. But he thinks some metaphysics goes wrong by assuming too much autonomy from science: there is a “resurgent idea that metaphysicians have a wider domain of study than scientists.”  As a result:

Today metaphysics is again the target of deep suspicion. In fact, we are in the midst of a flare-up of historic proportions. Evidence of this comes from my bookshelf. Many recent books in philosophy of science possess entire chapters strongly condemning comtemportary analytic metaphysics.

Thursday, January 14, 2010

Another Argument for Emergent Gravity

I have followed with interest a growing body of opinion among physicists that gravity (and space itself) is best thought of as an emergent phenomenon (most recently here).  Erik Verlinde has a paper, called On the Origin of Gravity and the Laws of Newton, which presents a heuristic case for gravity as emergent.

Unlike most of the other research papers I've blogged about, this is not a quantum gravity theory, but rather uses a number of concepts in mainstream physics (thermodynamics, the holographic principle) to derive emergent gravity.  He says that if one coarse grains a microscopic theory (whose precise dynamics need not be known), and applies the holographic principle to measure information on partition screens between particles, the information on the screens will give rise to an entropic force - this is gravity.

The paper has engendered discussion (I first saw it mentioned by Peter Woit here;  there is some appreciation here, and criticism here -- Verlinde responds here).  The main criticisms are that Verlinde's points are either not new, or that they embody circular reasoning (since concepts from Newtonian and post-Newtonian physics are used to derive Newtonian gravity).  Verlinde responds that he is bringing out a new insight which should help convince people that gravity is not a fundamental force, but is emergent.

I can't adjudicate the disagreements, but I think it's very suggestive that the argument for emergence continues to gain adherents.

I also think it is interesting to note that in Verlinde's model the microscopic theory, while not defined in any detail, must have a well-defined asymmeterical time dimension, as in the emergent quantum gravity theories I've reviewed.  "Time is fundamental, while space is not".

[UPDATE 22 Jan.2010:  A couple of more related links (HT).  A New Scientist article, and an illuminating preprint from Lee Smolin, who works through a Verlinde-type derivation in a different way, utilizing ideas from Loop Quantum Gravity research (altho note the specifics of LQG are actually not very important to the analysis).  He does a very good job placing the Verlinde work in context of other research and shows where it seems to add new value.]

Wednesday, January 06, 2010

Templeton Funds Initiative in Evolutionary Biology

[See also updates at the end of the post]

I just saw the news (here - I’m not sure if this was made public earlier) about the John Templeton Foundation's $10 million multi-part grant to fund “Foundational Questions in Evolutionary Biology” (FQEB), an initiative to be led by Harvard’s Martin Nowak.

Nowak has led what is called the Program for Evolutionary Dynamics at Harvard and has focused on the mathematical modeling side of evolutionary studies. The first announced effort is to offer fellowships to scholars pursuing envelope-pushing work on topics in evolution as well as the study of the origin of life.

I would like to learn more about this, but here are a few tidbits from the above links which are interesting. While the name evokes the earlier Templeton funding of the Foundational Questions Institute (FQXi), this program is more geographically centered (in Boston) and so, while not involving a new independent physical institute, it nonetheless is less “virtual” than FQXi. FQXi exists mainly to provide grants to scholars whose work in foundational physics might not otherwise garner funding from traditional sources. FQEB seem to be more people-driven (and Harvard/Boston oriented), and Nowak’s role seems crucial.

Importantly to me, however (as someone who watches Templeton -- see here and here -- and “roots” for them to apply their vast resources wisely), the initiative raises more potential controversy in terms of whether pure science will result from this effort versus a bias to search out and rationalize religion-friendly results. (This is not an issue with FQXi, which I think anyone who supports pure physics would be at least broadly pleased with):

  • The stated goal includes a reference to "understandings of teleology and concepts of ultimate purpose".
  • A Templeton officer says a “next phase of FQEB” will include “rigorous integrative work” with scholars in philosophy and theology. 
  • The board includes a Divinity professor(!)
  • Nowak, who has had affiliations with Templeton for some time, is himself is a committed Christian (was this a necessary if not sufficient fact in spurring this initiative?). A short essay where he expresses some of his views is here.
 The reason this is concerning, obviously, is that this country has faced an long and ongoing challenge to keep education in evolutionary biology free from interference from misguided religious folks.  The Templeton Foundation has disavowed any support for the most prominent recent political agitators in this area – the “Intelligent Design” movement -- and I think their efforts in supporting science/religion rapprochement have been harmless (if often wasteful, in my opinion). But why make a big effort in science funding in this crucial and sensitive area (which is a wonderful idea) and then contaminate it with any religiosity at all? That concerns me and I’m worried that it is a big mistake.

[UPDATE 8 Jan.2010: It seems the Templeton newsletter emailed to me on 6th January, which is my first link above, was the first public notice of this; the next blogosphere notice was today and comes from the "Intelligent Design" promoter, William Dembski, here. My brief opinion of ID is above and in an earlier blog post here.]

[UPDATE 20 Jan.2010: Templeton has announced funding priorities for the new year, and, of interest to this blog, they include Quantum Physics and the Nature of Reality and Foundational Questions in the Mathematical Sciences.]

[UPDATE 21 Jan. 2010: Also interesting to me is Templeton’s recruiting of journalist and blogger Rod Dreher to a post called a director of publications. His new blog is here (the first post is here). I assume it is no accident that he is a Christian conservative. There seems to be plenty of circumstantial evidence of an ongoing tension at JTF between the late founder’s clearly non-sectarian, progressive view of the religious impulse and the current Christian conservative leadership.]

Monday, January 04, 2010

A Crystallizing Universe

The use of a phase transition to describe reality pops up in this paper by George Ellis and Tony Rothman: “Time and Spacetime: The Crystallizing Block Universe.”

I had previously read Ellis’ contribution to the FQXi contest on time: “On the Flow of Time”. In that essay, Ellis criticized the notion of picturing the universe as an unchanging four-dimensional space-time block, and proposed a model of an “Evolving Block Universe”, which includes the indispensable notion of time flow. In this new paper, Ellis and Rothman fine-tune this idea.

They associate the flow of time with the transition from a quantum future to a classical past: this transition is marked by the time-irreversible process of quantum state-vector reduction (measurement). They note, however, that phenomena displayed in certain quantum set-ups (delayed choice and quantum eraser schemas) show that the transition process doesn’t take place uniformly. This non-uniform nature of the transition inspired the crystallization metaphor.

I like that Ellis takes quantum measurement seriously as a natural process (actualizing potentialities) and links this transition to the experienced flow of time.