I really enjoyed this paper: The Free Will Theorem, by Princeton Mathematics Dept. luminaries John H. Conway and Simon B. Kochen (HT: Clark’s sidebar, which linked to this Garden post, which linked in turn to this Times article).
Using axioms which implement an idealized EPR-style quantum spin measurement experiment (and assuming relativity), the authors set out to prove that:
If the choice of directions in which to perform spin 1 experiments is not a function of the information accessible to the experimenters, then the responses of the particles are equally not functions of the information accessible to them.
They call this the Free Will theorem since we in practice assume experimenters are free to set up the experiment the way they wish. So, the authors are not proving free will exists, they are proving that if free will exists at the human level, then the outcome exhibited by elementary particles will also be free.
The proof seems fairly straightforward once one accepts the earlier Kochen-Specker theorem (it can’t be said that the spin values for each direction already exist prior to measurement).
Following the presentation of the proof, the authors show (by discussing a way to modify Bohm’s theory) that QM is logically consistent if one assumes the assumption of particles expressing free will in a relativistic framework. Next, they relax some of the idealized assumptions to establish the robustness of the result in a more real world context.
The next section discusses how this result furthers the process (earlier marked by the K-S theorem and Bell's Theorem) of making hidden variable theories unworkable. They also argue it is an obstacle for GRW-type collapse models.
Further tidbits:
The authors argue that it is incorrect to interpret EPR-style experiments as meaning there is faster-than-light communication between particles; the particles are entangled as a collective system, but one will not confirm the predicted correlation until the future measurement of the other member of the pair. This is congruent with the perspective of Smerlak and Rovelli’s recent paper which interprets EPR from the perspective of relational quantum mechanics (RQM).
In terms of interpreting quantum mechanics: the authors argue quantum states (between measurements) are merely predictors (with probabilities) of what will happen if various measurements are performed. It is a mistake to ascribe concrete reality to the quantum states. This again is consistent with RQM’s perspective that it is the measurement events which are concretely real. The authors also state briefly that they don’t believe a conscious human mind is needed for collapse, but they don’t discuss in detail what they think is necessary. They think a future physics will explain what sort of “texture” surrounding a system will cause collapse.
The authors offer some philosophical remarks on free will. First, they remind the reader that they don’t claim to prove free will. They say “determinism, like solipsism, is logically possible.” They themselves do subscribe, however, to what a philosopher would call a naïve folk conception of libertarian free will. They don’t see how science could be taken seriously if its practitioners weren’t free to investigate nature by choosing what experiments to perform.
In any case, the linking of free will at the human level to free or spontaneous outcomes at the level of elementary quantum systems is an important result. It is also an especially appealing idea to a panexperientialist like me. While I appreciate the substantial problems which afflict the folk conception of free will, the results of this paper fit with my view that the conscious experience, intentionality, and (at least limited) free agency of human beings are all sourced from fundamental and ubiquitous properties of the natural world.
I also want to comment on a section toward the end entitled “Free versus Random?” It is extremely common to interpret QM as meaning the universe contains a fundamental indeterminism, but it is unusual to say it implies the existence of a fundamental freedom. Here’s a point the authors make in favor of the latter:
“Although we find ourselves unable to give an operational definition of either “free” or “random,” we have managed to distinguish between them in our context, because free behavior can be twinned, while random behavior cannot (a remark that might also interest some philosophers of free will).”
“Twinned” here refers to the entanglement of two particles. The measurement of the first of the twinned pair enables us to predict the outcome of the measurement of the second, so they aren’t individually random events. But I’m not sure this is a good argument: are we conflating the idea of a particle’s randomness with its independence? I’ll have to give this more thought.
I’m very interested in arguments which support my contention that the worldview implied by QM is richer and much more interesting than just classical physics plus an overlay of randomness. It isn’t just that the measurement outcome is random vs. determined. The quantum measurement event has intrinsically more to it than a classical billiard-ball notion of a causal event. It is an interaction between two systems where one system’s propensity toward an outcome is actualized by the second (measuring) system. I believe this actualization event or process carries with it the raw material of agency (as well as experience).
Wednesday, May 31, 2006
Tuesday, May 23, 2006
The Intelligent Cell
A couple of correspondents have pointed me toward the work of Guenter Albrecht-Buehler, whose research and ideas are summarized on a website entitled Cell Intelligence.
The website is organized in a table of contents. In approaching it, one finds some radical claims in the first section, and I was at first put off by this. On second look, I found it useful to proceed a bit backwards in assessing the information on the site, much of which I found intriguing.
Section 3 of the contents includes what would seem to be an important research finding, where he shows that cells (“3T3” cells, which I gather are from a mouse embryo) detect and react to microscopic infra-red light sources at a distance. References on the site show that these experiments (as well as other Albrecht-Bueller results) have been published in mainstream journals. I do not know whether other researchers have replicated them.
It is interesting to think about how a cell might utilize light alongside its use of chemical-mechanical processes. There is a section discussing a proposal that a structure called the centriole detects the light, and one discussing microtubules as possibly the transmission mechanism for relaying this signal within the cell (of course, this triggered a memory of the role microtubles played in the Penrose Hameroff quantum brain proposal!).
Crucial to Albrecht-Buehler’s overall thesis is that the cells themselves are light sources: he thinks they scatter ambient radiation in a patterned way, with this radiation then utilized as a signal input by its neighbors (including at some distance). He shows some research which seems to indicate this scattered light is used in organizing “social” behavior among a group of cells.
This idea ties back into section 2 of the site, where intriguing behavioral properties of cells are discussed. Albrecht-Beuhler says that the data indicate that signals, rather than mechanisms, are being utilized in individual and group behaviors, and that the cell must be processing information in order to manifest such behaviors.
This is the basis for asserting that cells are worthy of being considered intelligent in the way characterized in the opening summary and in section 1, which now make more sense.
So, is there signal processing going on in cells? Do cells control and direct their processes in a top-down way, rather than being built strictly from bottom-up chemical processes? Do they utilize electro-magnetic signals specifically? I’m in a poor position to judge all this (knowing even less about biology than about other topics I blog here about). But I’m intrigued, and will keep these proposals in mind as I read more going forward.
The website is organized in a table of contents. In approaching it, one finds some radical claims in the first section, and I was at first put off by this. On second look, I found it useful to proceed a bit backwards in assessing the information on the site, much of which I found intriguing.
Section 3 of the contents includes what would seem to be an important research finding, where he shows that cells (“3T3” cells, which I gather are from a mouse embryo) detect and react to microscopic infra-red light sources at a distance. References on the site show that these experiments (as well as other Albrecht-Bueller results) have been published in mainstream journals. I do not know whether other researchers have replicated them.
It is interesting to think about how a cell might utilize light alongside its use of chemical-mechanical processes. There is a section discussing a proposal that a structure called the centriole detects the light, and one discussing microtubules as possibly the transmission mechanism for relaying this signal within the cell (of course, this triggered a memory of the role microtubles played in the Penrose Hameroff quantum brain proposal!).
Crucial to Albrecht-Buehler’s overall thesis is that the cells themselves are light sources: he thinks they scatter ambient radiation in a patterned way, with this radiation then utilized as a signal input by its neighbors (including at some distance). He shows some research which seems to indicate this scattered light is used in organizing “social” behavior among a group of cells.
This idea ties back into section 2 of the site, where intriguing behavioral properties of cells are discussed. Albrecht-Beuhler says that the data indicate that signals, rather than mechanisms, are being utilized in individual and group behaviors, and that the cell must be processing information in order to manifest such behaviors.
This is the basis for asserting that cells are worthy of being considered intelligent in the way characterized in the opening summary and in section 1, which now make more sense.
So, is there signal processing going on in cells? Do cells control and direct their processes in a top-down way, rather than being built strictly from bottom-up chemical processes? Do they utilize electro-magnetic signals specifically? I’m in a poor position to judge all this (knowing even less about biology than about other topics I blog here about). But I’m intrigued, and will keep these proposals in mind as I read more going forward.
Tuesday, May 16, 2006
The Coherent Organism
Following suggestions from Mike Wiest in his comment on this post, I’ve been reading more on efforts to invoke quantum physics in explaining life. Below are my thoughts following my reading of Mae-Wan Ho’s The Rainbow and The Worm: The Physics of Organisms.
This is an engaging and thought-provoking book, extremely dense with information and ideas running from accepted science through increasingly speculative extrapolations and concluding with some free-form philosophizing. This book was published in 1993, with the second edition I read coming in 1998. Ho, who was trained as a biochemist, has since been involved in leading an organization called the Institute of Science in Society, and her more recent writings tend toward public policy.
The early sections of Ho’s book discuss life in thermodynamic terms. I was broadly familiar with the idea that life utilizes energy flow to build and maintain high levels of structural organization far from equilibrium. In several steps, and citing work of other scientists, she builds a case that explaining life in detail strains the traditional thermodynamic picture (which assumes microscopic homogeneity). She says intricately organized living things utilize molecular systems which transfer energy without thermalization (zero entropy growth). Energy is stored and used at the electronic level, not the thermal level. But how can these micro-level energy exchanges operate across the macroscopic dimensions of the organism? Ho says stored energy can amplify weak signals across larger distances.
Throughout these early chapters, Ho uses the word “coherent” to describe the (non-thermal) energy storage and transfer within the organism (she says stored energy is by definition coherent energy). She will come back to this idea later in the book and explicitly argue that it must involve quantum coherence specifically.
The energy we’re talking about is electromagnetic. We know electrons move quickly and in organized fashion through crystals and super-cooled materials (superconductors). Could something like that be happening in the organism (despite the high temperature)? Ho uses the example of a solid state laser where energy flow induces a quantum phase transition which can take place very rapidly. She sketches how this might occur in living tissue and discusses the idea that cells could be solid state systems.
In a later chapter Ho leaves aside the solid state system model of the organism in favor of specifically identifying it as a liquid crystal system. She became convinced of this in part by examining fruit fly larva under a polarizing microscope. The title of the book comes from the colorful organized patterns she detected. She believes the type of organization seen is evidence that organisms are essentially liquid crystals.
What other evidence is there that organisms are coherent systems? A piece of possible evidence is in the analysis of the electro-magnetic fields emitted by organisms. It seems well supported that organisms do generate weak electromagnetic fields, and are in turn sensitive to external fields. Ho cites the work of Fritz Popp and colleagues who have analyzed the emission of light (“bio-photons”) from organisms such as fruit fly embryos. (A list of Popp’s publications can be found here). The pattern of photons issued in response to stimulus is said to be consistent with non-classical coherence. This may lend some credence to the idea that a coherent field may be providing organization to the organism.
Ho has a chapter toward the end of the book on quantum physics. She summarizes the familiar phenomena of quantum entanglement and coherence (2 slit experiment, EPR, etc.). Then she tries to convey why the ideas and arguments of the preceding chapters lead her to conclude it is indeed quantum coherence (superposition of states, non-local entanglement) which prevails in the organism. But has she made the case? In a key passage she says:
“I have been presenting heuristic arguments throughout many of the preceding Chapters on why the wholeness of organisms has to be understood as quantum coherence.”
This is followed by a brief summary of some of the earlier ideas; then:
“By far the most persuasive argument for quantum coherence, to my mind, is the nature of the coordination that is achieved in the organism, where every single part…is able to work autonomously while keeping in step and in tune with the whole.”
I think she is conceding that her case, which is admirably detailed and suggestive, is ultimately circumstantial. Now, criminals are convicted every day by circumstantial evidence, so I don’t mean to be dismissive here. But for the mainstream scientific community to get on board, we’ll need more.
As Paul Davies said, we need a secure experimental result which demonstrates a biological system clearly exploiting non-trivial quantum effects.
One area I do want to follow up on is this idea of an organism or cell as a liquid crystal. Saying something is a liquid crystal is not the same as saying it is coherent in the quantum sense. But liquid crystals and other phenomena of condensed matter physics demonstrate intriguing properties. And the scales at which these occur is small enough require quantum as well as classical theoretical tools to investigate. The emergent features found in some of these systems (some discussed in Robert Laughlin’s A Different Universe, which I discussed in this post) are mysterious in their own right, and if biological systems do exhibit characteristics of some of these, that would be very interesting to investigate.
This is an engaging and thought-provoking book, extremely dense with information and ideas running from accepted science through increasingly speculative extrapolations and concluding with some free-form philosophizing. This book was published in 1993, with the second edition I read coming in 1998. Ho, who was trained as a biochemist, has since been involved in leading an organization called the Institute of Science in Society, and her more recent writings tend toward public policy.
The early sections of Ho’s book discuss life in thermodynamic terms. I was broadly familiar with the idea that life utilizes energy flow to build and maintain high levels of structural organization far from equilibrium. In several steps, and citing work of other scientists, she builds a case that explaining life in detail strains the traditional thermodynamic picture (which assumes microscopic homogeneity). She says intricately organized living things utilize molecular systems which transfer energy without thermalization (zero entropy growth). Energy is stored and used at the electronic level, not the thermal level. But how can these micro-level energy exchanges operate across the macroscopic dimensions of the organism? Ho says stored energy can amplify weak signals across larger distances.
Throughout these early chapters, Ho uses the word “coherent” to describe the (non-thermal) energy storage and transfer within the organism (she says stored energy is by definition coherent energy). She will come back to this idea later in the book and explicitly argue that it must involve quantum coherence specifically.
The energy we’re talking about is electromagnetic. We know electrons move quickly and in organized fashion through crystals and super-cooled materials (superconductors). Could something like that be happening in the organism (despite the high temperature)? Ho uses the example of a solid state laser where energy flow induces a quantum phase transition which can take place very rapidly. She sketches how this might occur in living tissue and discusses the idea that cells could be solid state systems.
In a later chapter Ho leaves aside the solid state system model of the organism in favor of specifically identifying it as a liquid crystal system. She became convinced of this in part by examining fruit fly larva under a polarizing microscope. The title of the book comes from the colorful organized patterns she detected. She believes the type of organization seen is evidence that organisms are essentially liquid crystals.
What other evidence is there that organisms are coherent systems? A piece of possible evidence is in the analysis of the electro-magnetic fields emitted by organisms. It seems well supported that organisms do generate weak electromagnetic fields, and are in turn sensitive to external fields. Ho cites the work of Fritz Popp and colleagues who have analyzed the emission of light (“bio-photons”) from organisms such as fruit fly embryos. (A list of Popp’s publications can be found here). The pattern of photons issued in response to stimulus is said to be consistent with non-classical coherence. This may lend some credence to the idea that a coherent field may be providing organization to the organism.
Ho has a chapter toward the end of the book on quantum physics. She summarizes the familiar phenomena of quantum entanglement and coherence (2 slit experiment, EPR, etc.). Then she tries to convey why the ideas and arguments of the preceding chapters lead her to conclude it is indeed quantum coherence (superposition of states, non-local entanglement) which prevails in the organism. But has she made the case? In a key passage she says:
“I have been presenting heuristic arguments throughout many of the preceding Chapters on why the wholeness of organisms has to be understood as quantum coherence.”
This is followed by a brief summary of some of the earlier ideas; then:
“By far the most persuasive argument for quantum coherence, to my mind, is the nature of the coordination that is achieved in the organism, where every single part…is able to work autonomously while keeping in step and in tune with the whole.”
I think she is conceding that her case, which is admirably detailed and suggestive, is ultimately circumstantial. Now, criminals are convicted every day by circumstantial evidence, so I don’t mean to be dismissive here. But for the mainstream scientific community to get on board, we’ll need more.
As Paul Davies said, we need a secure experimental result which demonstrates a biological system clearly exploiting non-trivial quantum effects.
One area I do want to follow up on is this idea of an organism or cell as a liquid crystal. Saying something is a liquid crystal is not the same as saying it is coherent in the quantum sense. But liquid crystals and other phenomena of condensed matter physics demonstrate intriguing properties. And the scales at which these occur is small enough require quantum as well as classical theoretical tools to investigate. The emergent features found in some of these systems (some discussed in Robert Laughlin’s A Different Universe, which I discussed in this post) are mysterious in their own right, and if biological systems do exhibit characteristics of some of these, that would be very interesting to investigate.
Tuesday, May 02, 2006
Saving Reduction
Reductive explanations are at the heart of effective scientific investigation. And yet in the past I’ve argued that in the case of first-person experience (FPE), a normal approach to physical reduction will fail. A reduction of experience to wholly non-experiential parts will eliminate what we seek to explain. Equivalently, the ontological emergence of FPE from wholly non-experiential parts is incoherent. This argument was at the heart of the Galen Strawson paper linked to in the last post.
Now emergence and reduction are difficult topics. But it appears to me that attempts to give an account of genuine ontological emergence for any phenomenon must fail, given an assumption of physicalism.
This case is argued by William Seager in a recent paper appearing in the JCS (full text unfortunately not online). Seager argues that candidates for emergence, assuming a normal physicalist worldview, are really only epistemological or explanatory forms of emergence. For a contrasting view which defends a notion of “weak” ontological emergence consistent with physicalism, see this paper by Jessica Wilson in the new online philosophy conference. On my first read, my impression is that Wilson’s approach (which invokes reduced degrees of freedom as a way to define emergent structures) is of limited metaphysical help in terms of my interest in this topic (note she is not taking on the case of consciousness per se in this paper).
The problem is you can’t seem to get something ontologically brand-new in the macroscopic realm from mereological combinations of classical physical objects.
But what if we could reduce things to elementary entities which had a richer ontology? Could we then “save” reduction as an explanatory method for consciousness (and perhaps other difficult-to-explain phenomena)?
I’m going to cut this post short, because I know I’m repeating myself. I think the answer is yes, if we adopt an event ontology in which the fundamental entity is an actualization of a possibility. Science has already discovered these fundamental events in the form of quantum measurements. A network of such events offers a framework upon which the rich phenomena of the world, including conscious individuals, can be composed.
Now emergence and reduction are difficult topics. But it appears to me that attempts to give an account of genuine ontological emergence for any phenomenon must fail, given an assumption of physicalism.
This case is argued by William Seager in a recent paper appearing in the JCS (full text unfortunately not online). Seager argues that candidates for emergence, assuming a normal physicalist worldview, are really only epistemological or explanatory forms of emergence. For a contrasting view which defends a notion of “weak” ontological emergence consistent with physicalism, see this paper by Jessica Wilson in the new online philosophy conference. On my first read, my impression is that Wilson’s approach (which invokes reduced degrees of freedom as a way to define emergent structures) is of limited metaphysical help in terms of my interest in this topic (note she is not taking on the case of consciousness per se in this paper).
The problem is you can’t seem to get something ontologically brand-new in the macroscopic realm from mereological combinations of classical physical objects.
But what if we could reduce things to elementary entities which had a richer ontology? Could we then “save” reduction as an explanatory method for consciousness (and perhaps other difficult-to-explain phenomena)?
I’m going to cut this post short, because I know I’m repeating myself. I think the answer is yes, if we adopt an event ontology in which the fundamental entity is an actualization of a possibility. Science has already discovered these fundamental events in the form of quantum measurements. A network of such events offers a framework upon which the rich phenomena of the world, including conscious individuals, can be composed.
Thursday, April 20, 2006
Thank You Galen Strawson
[Updated 16 March 2009: Broken link. Strawson has a new home page here; but the link to his paper below is unfortunately gone. A revised version of the paper with commentary and Strawson's replies are collected in this book (actually a special edition of the Journal of Consciousness Studies.]
Hat tip goes to this post by Justin. Galen Strawson's new paper persuasively makes the straightforward argument:
1. Experience is a fundamental part of the world.
2. Emergence of experience from wholly non-experiential parts is incoherent.
3. From 1 and 2, panexperientialism is entailed.
Better yet, he does this an a very entertaining style -- sort of like your grouchy uncle who has run out of patience with impertinent nonsense (if said uncle was also an excellent philosopher).
Hat tip goes to this post by Justin. Galen Strawson's new paper persuasively makes the straightforward argument:
1. Experience is a fundamental part of the world.
2. Emergence of experience from wholly non-experiential parts is incoherent.
3. From 1 and 2, panexperientialism is entailed.
Better yet, he does this an a very entertaining style -- sort of like your grouchy uncle who has run out of patience with impertinent nonsense (if said uncle was also an excellent philosopher).
Tuesday, April 18, 2006
Notes from Tucson
I was fortunate to be able to attend a good portion of the Toward a Science of Consciousness 2006 conference in Tucson. This seventh biennial event, sponsored by the University of Arizona’s Center for Consciousness Studies, brings together all strands of inquiry into consciousness, including neuroscience, cognitive science, psychology, philosophy, physics and more. The conference had 500+ attendees and while I understand it used to be even larger, I can attest it was very robust and diverse. In addition to the main stage talks there was an unbelievably rich set of concurrent talks (most of which I missed) and poster presentations. It seems to me that the topic demands an interdisciplinary forum like this, and Tucson ably fills the role. I met and spoke to a number of interesting people there; everyone was extremely nice and there was a great vibe to the proceedings.
Below are notes on three of the talks I heard, those of Giulio Tononi, John Searle, and Paul Davies. I may look to add more later on.
Uriah Kriegel has 2 posts at Desert Landscapes about the conference (here and here). Unfortunately, I did not get a chance to meet Uriah, but happily did catch his main stage talk, where he effectively presented his self-representational theory of consciousness.
I. Giulio Tononi presented his information integration theory of consciousness. He was a very effective speaker and made a strong case for his work.
Here are a few of his preliminary remarks. Many have searched for “the” neural correlate of consciousness. Attempts to localize the phenomenon have not worked well. Today many think the correlate is in widely distributed thalamocortical activity. (But as an aside, attempts to identify a synchronicity mechanism for binding brain states is not promising and Tononi doesn’t seem to see a need for something like synchronization via 40 hz oscillation).
A couple of other thoughts: consciousness is more than introspective/reflective/higher-order self-consciousness. It is more and essentially simpler. It also goes beyond consciousness of the environment (dreams show us there is something of a world inside the skull).
Tononi offers these 2 paradoxes help us to think about consciousness (to which he returns at the end):
1. Why is the correlate in the cerebrum, not the cerebellum? The cerebellum has even more neurons, connections.
2. Why is it present in wakefulness rather than (non-REM) sleep?
Here’s a brief summary of Tononi’s approach (warning: these notes are taken on the fly and may do a poor job outlining the theory).
We have a large differentiated repertoire of possible states. Each state conveys a lot of information about itself as well as ruling out all other states. Also, each state is integrated (you cannot really subdivide it).
Tononi will use mathematics to characterize this phenomenology. Define “effective information” to be the entropy obtained by part of a system when you perturb another part. The minimum information partition you can put into the system (the ‘weakest’ link) will be used to define this. This can be measured, and is a measure of information integration.
It turns out that to maximize information integration, all elements in the system should participate by connecting to each other, but with non-uniform number and/or pattern of connections. Fewer connections is bad, but so is uniformity/simplicity of connections (specialization is good).
Analysis of the thalamocortical system shows that it has the right combination of specialization and integration to maximize effective information in the system. The cerebellum, in contrast, consists of separated modular systems which are not well integrated. Analysis of waking vs. sleeping states also shows how consciousness is correlated with this combination.
My summary thoughts: First, one implication I think is important is that consciousness is a graded phenomenon, not an all-or-nothing one. Second, it must be noted that a theory of this sort does not explain the interior/subjective and qualitative nature of consciousness (the hard problem). However, it impressed me and other listeners as presenting a good path for exploring how the particular richness as well as cognitive effectiveness of human consciousness is grounded in brain organization.
II. John Searle is an excellent speaker and I’m glad I got a chance to hear him talk. For those who take the “hard problem” seriously, however, Searle remains annoying. His talk was entitled "Dualism Revisited"
Searle defines consciousness as qualitative, subjective, unified and intrinsically intentional. He asserts consciousness is real and irreducible. Functional or behavioral approaches cannot explain consciousness (he has always been effective with his criticism of these).
He then says consciousness is caused in the brain by low-level neuronal processes, and is realized in the brain as a higher-level or system feature. Consciousness is a biological (specifically neurobiological) phenomenon.
He insists despite its irreducible first person ontology, consciousness just is a biological fact in the world. Once we have a good neurobiological theory, it will show how neuronal processes cause consciousness, and then we will be done.
He wants to say that the hard problem is just a conceptual confusion. We have different levels of description of the phenomena, but he denies this shows a need for any special further explanation. He uses (in my opinion) faulty analogies regarding different levels of description of say, an automobile engine (faulty because both levels are third-person, not first and third!). “Just stop worrying about it!” is the message.
Later in Searle’s talk, he speculated about why progress in explaining consciousness in neuroscientific terms so far seems to be slow. His answer was that the work focuses on localized phenomena and not enough on the large scale conscious “field”. These comments were in tune with some of Tononi’s mentioned above about the problem researchers have had when trying to localize the NCC.
III. Paul Davies on quantum biology and on a possible link between cosmology and strong emergence.
Paul Davies discussed his exploration of a number of speculative ideas which could advance our understanding of life and mind. First he discussed the view that quantum mechanics has something to contribute to this understanding.
He said that are 2 ways QM could play a role in life. First, a negative effect, with quantum indeterminacy limiting efficiency at the micro-level. Second, a positive effect, where life actually harnesses or exploits QM to improve efficiency or accomplish difficult tasks (with a comparison to the potential gains present in quantum computing).
Davies said there is plenty of circumstantial evidence for the role of QM in life. Certainly, we know many small biological structures do operate on the “quantum edge” in terms of their size. He gave a few examples of this.
He also discussed his suspicion that QM played a role on the origin of life (OOL). He very briefly outlined an idea of “quantum replicators” which could have been simpler precursors of living things.
He discussed the biggest challenge for quantum biology, which is decoherence. Simple models and experimental results indicate that quantum systems decohere very rapidly. But he says we may not know the whole story yet, and there may be environments where coherence can be sustained.
The next subject was on the subject of QM interpretations and whether there was an objective environmental trigger of wave function collapse (such as Roger Penrose’ idea that gravity plays a role). Davies discussed the idea that a specified level of complexity could engineer the collapse of the wave function and define the microscopic/macroscopic frontier. Quoting Seth Lloyd’s idea of the universe as a quantum computer, he said one could estimate the large but finite amount of classical information the universe can contain. He quoted an estimate of 10^120 bits. Quantum systems leveraging coherence can handle a huge amount of information, but perhaps the finite cosmological limit cuts off the size of these coherent quantum systems. A system of, say, 400 or so entangled particles could represent the approximate limit given this complexity ceiling imposed by the cosmos.
Finally, if there is indeterminacy due to a finite information capacity of the universe, then Davies said this could remove the obstacle to micro-level causal closure of the universe, and open the door to downward causation. “Physical systems are causally open when they reach a certain level of complexity – a level determined by the information processing capacity of the universe.” The origin of consciousness may lie within the quantum to classical transition at this critical threshold.
I like Davies a lot. At this point in his career he has been freed by his publishing success, Templeton prize, etc. to engage in diverse speculations rather than work within normal academic boundaries. But he is a very serious fellow. The main virtue being that even if these ideas have a very small chance of being correct, the fact that they would be very big deals if they did work out makes it worthwhile.
I got to talk with him in the lobby of the amphitheatre briefly and asked what he thought it would take to get more serious research time and money allocated to quantum biology. He said we needed a result that was both secure and non-trivial. He said we do have evidence of quantum level mechanisms in biology (citing enzymes and proton tunneling in DNA mutation), but these are relatively trivial, not interesting, effects. There are many leads to follow, though, and he is optimistic about some research which is underway.
Below are notes on three of the talks I heard, those of Giulio Tononi, John Searle, and Paul Davies. I may look to add more later on.
Uriah Kriegel has 2 posts at Desert Landscapes about the conference (here and here). Unfortunately, I did not get a chance to meet Uriah, but happily did catch his main stage talk, where he effectively presented his self-representational theory of consciousness.
I. Giulio Tononi presented his information integration theory of consciousness. He was a very effective speaker and made a strong case for his work.
Here are a few of his preliminary remarks. Many have searched for “the” neural correlate of consciousness. Attempts to localize the phenomenon have not worked well. Today many think the correlate is in widely distributed thalamocortical activity. (But as an aside, attempts to identify a synchronicity mechanism for binding brain states is not promising and Tononi doesn’t seem to see a need for something like synchronization via 40 hz oscillation).
A couple of other thoughts: consciousness is more than introspective/reflective/higher-order self-consciousness. It is more and essentially simpler. It also goes beyond consciousness of the environment (dreams show us there is something of a world inside the skull).
Tononi offers these 2 paradoxes help us to think about consciousness (to which he returns at the end):
1. Why is the correlate in the cerebrum, not the cerebellum? The cerebellum has even more neurons, connections.
2. Why is it present in wakefulness rather than (non-REM) sleep?
Here’s a brief summary of Tononi’s approach (warning: these notes are taken on the fly and may do a poor job outlining the theory).
We have a large differentiated repertoire of possible states. Each state conveys a lot of information about itself as well as ruling out all other states. Also, each state is integrated (you cannot really subdivide it).
Tononi will use mathematics to characterize this phenomenology. Define “effective information” to be the entropy obtained by part of a system when you perturb another part. The minimum information partition you can put into the system (the ‘weakest’ link) will be used to define this. This can be measured, and is a measure of information integration.
It turns out that to maximize information integration, all elements in the system should participate by connecting to each other, but with non-uniform number and/or pattern of connections. Fewer connections is bad, but so is uniformity/simplicity of connections (specialization is good).
Analysis of the thalamocortical system shows that it has the right combination of specialization and integration to maximize effective information in the system. The cerebellum, in contrast, consists of separated modular systems which are not well integrated. Analysis of waking vs. sleeping states also shows how consciousness is correlated with this combination.
My summary thoughts: First, one implication I think is important is that consciousness is a graded phenomenon, not an all-or-nothing one. Second, it must be noted that a theory of this sort does not explain the interior/subjective and qualitative nature of consciousness (the hard problem). However, it impressed me and other listeners as presenting a good path for exploring how the particular richness as well as cognitive effectiveness of human consciousness is grounded in brain organization.
II. John Searle is an excellent speaker and I’m glad I got a chance to hear him talk. For those who take the “hard problem” seriously, however, Searle remains annoying. His talk was entitled "Dualism Revisited"
Searle defines consciousness as qualitative, subjective, unified and intrinsically intentional. He asserts consciousness is real and irreducible. Functional or behavioral approaches cannot explain consciousness (he has always been effective with his criticism of these).
He then says consciousness is caused in the brain by low-level neuronal processes, and is realized in the brain as a higher-level or system feature. Consciousness is a biological (specifically neurobiological) phenomenon.
He insists despite its irreducible first person ontology, consciousness just is a biological fact in the world. Once we have a good neurobiological theory, it will show how neuronal processes cause consciousness, and then we will be done.
He wants to say that the hard problem is just a conceptual confusion. We have different levels of description of the phenomena, but he denies this shows a need for any special further explanation. He uses (in my opinion) faulty analogies regarding different levels of description of say, an automobile engine (faulty because both levels are third-person, not first and third!). “Just stop worrying about it!” is the message.
Later in Searle’s talk, he speculated about why progress in explaining consciousness in neuroscientific terms so far seems to be slow. His answer was that the work focuses on localized phenomena and not enough on the large scale conscious “field”. These comments were in tune with some of Tononi’s mentioned above about the problem researchers have had when trying to localize the NCC.
III. Paul Davies on quantum biology and on a possible link between cosmology and strong emergence.
Paul Davies discussed his exploration of a number of speculative ideas which could advance our understanding of life and mind. First he discussed the view that quantum mechanics has something to contribute to this understanding.
He said that are 2 ways QM could play a role in life. First, a negative effect, with quantum indeterminacy limiting efficiency at the micro-level. Second, a positive effect, where life actually harnesses or exploits QM to improve efficiency or accomplish difficult tasks (with a comparison to the potential gains present in quantum computing).
Davies said there is plenty of circumstantial evidence for the role of QM in life. Certainly, we know many small biological structures do operate on the “quantum edge” in terms of their size. He gave a few examples of this.
He also discussed his suspicion that QM played a role on the origin of life (OOL). He very briefly outlined an idea of “quantum replicators” which could have been simpler precursors of living things.
He discussed the biggest challenge for quantum biology, which is decoherence. Simple models and experimental results indicate that quantum systems decohere very rapidly. But he says we may not know the whole story yet, and there may be environments where coherence can be sustained.
The next subject was on the subject of QM interpretations and whether there was an objective environmental trigger of wave function collapse (such as Roger Penrose’ idea that gravity plays a role). Davies discussed the idea that a specified level of complexity could engineer the collapse of the wave function and define the microscopic/macroscopic frontier. Quoting Seth Lloyd’s idea of the universe as a quantum computer, he said one could estimate the large but finite amount of classical information the universe can contain. He quoted an estimate of 10^120 bits. Quantum systems leveraging coherence can handle a huge amount of information, but perhaps the finite cosmological limit cuts off the size of these coherent quantum systems. A system of, say, 400 or so entangled particles could represent the approximate limit given this complexity ceiling imposed by the cosmos.
Finally, if there is indeterminacy due to a finite information capacity of the universe, then Davies said this could remove the obstacle to micro-level causal closure of the universe, and open the door to downward causation. “Physical systems are causally open when they reach a certain level of complexity – a level determined by the information processing capacity of the universe.” The origin of consciousness may lie within the quantum to classical transition at this critical threshold.
I like Davies a lot. At this point in his career he has been freed by his publishing success, Templeton prize, etc. to engage in diverse speculations rather than work within normal academic boundaries. But he is a very serious fellow. The main virtue being that even if these ideas have a very small chance of being correct, the fact that they would be very big deals if they did work out makes it worthwhile.
I got to talk with him in the lobby of the amphitheatre briefly and asked what he thought it would take to get more serious research time and money allocated to quantum biology. He said we needed a result that was both secure and non-trivial. He said we do have evidence of quantum level mechanisms in biology (citing enzymes and proton tunneling in DNA mutation), but these are relatively trivial, not interesting, effects. There are many leads to follow, though, and he is optimistic about some research which is underway.
Thursday, March 30, 2006
Top-Down or Bottom-Up Quantum World?
At Antonio’s suggestion in his comments on the last post, I reviewed more of Ulrich Mohrhoff’s work on interpreting quantum physics contained in this paper and on his website, thisquantumworld. I also plowed through some of the debate between Mohrhoff (posting as koantum) and Patrick Van Esch (vanesch) on this thread at physicsforums. This was extremely fascinating although often over my head.
From my reading so far, Mohrhoff is saying two things which I think have some merit:
1. He rejects the assumption that the wave function represents something real. Many physicists extrapolate from the elegance of the idea of the deterministically evolving wave function to an ontological interpretation of QM (many-worlds or many minds) which tries to elevate this side of the story and minimize the measurement process. There is no quantum theory without measurements!
I’m sympathetic here, since while I believe the both of the quantum processes are fundamental, I think the measurement events are the “more real”: they constitute our concrete world while wave functions are the abstract possibility space available to be actualized by measurements (they are “real”, too, but not in a concrete sense).
2. While rejecting the naïve assumption that the wave function represents something real, Mohrhoff does want to find an objective description of reality which doesn’t appeal to consciousness. QM gives the probability distribution for unperformed measurements. It is a mistake to see these as subjective probabilities. They are objective probabilities.
I agree with this to an extent: I don’t see full-blown human consciousness as the sole avenue to measurement, and think natural systems implement measurements ubiquitously. However, in my view, the phenomenon of first-person consciousness is rooted in an experiential quality which is part of all measurement events (in the spirit of panexperientialist proposals such as Whitehead's or Gregg Rosenberg's).
But what is Mohrhoff’s positive proposal? What is “this quantum world”?
Here are some notes I took from his writing with my editorial comments in italics.
1. The world is intrinsically non-local. (Don’t be confused by thinking about the existence of a space-time background of points and instants – we contribute that to the theory, its not intrinsic).
2. Identical particles cannot be distinguished from each other independent of their possession of properties which can be distinguished.
So, these two statements imply that the quantum world cannot be built from the bottom up.
So how is it built? From the top-down.
“What ultimately exists is one. Call it whatever you like. Matter and space both come into being when this enters into (more or less fuzzy) spatial relations with itself…””…the relations are self-relations,”
This sounds like the world possesses a power of self-measurement. This is certainly an interesting rearrangement of the mystery, but I don’t see how it increases our understanding of reality.
Nothing has a property until it is measured (including the property of existing in a space-time continuum). Measurements create their outcomes (it isn’t that these properties are ontologically carried by the wave function between measurements). No measurements/no world.
OK (although I would say the wave function carries properties in their form as possibilities, and they are not created but made concrete when measured).
The macroscopic world is real in a way the microscopic world is not, since the probability of finding macro-objects where classically they should not be is very low. “… we must be allowed to look upon the positions of macroscopic objects – macroscopic positions, for short—as instrinsic, as self-indicating, or as real per se.” “The ‘foundation’ is the macroworld… not the micro-world.” “As philosophers would say, the properties of the quantum domain supervene on the goings-on in the classical domain.”
But the existence of macroscopic objects is just a primitive in this interpretation. This top-down view is equivalent to saying we just can't explain macroscopic events or objects. I find this unsatisfactory. I want to see us build an improved bottom-up explanation of the world, where the raw material is a property dualism matching the properties embedded in the quantum probability space with an “ability to measure” property possessed by natural systems.
From my reading so far, Mohrhoff is saying two things which I think have some merit:
1. He rejects the assumption that the wave function represents something real. Many physicists extrapolate from the elegance of the idea of the deterministically evolving wave function to an ontological interpretation of QM (many-worlds or many minds) which tries to elevate this side of the story and minimize the measurement process. There is no quantum theory without measurements!
I’m sympathetic here, since while I believe the both of the quantum processes are fundamental, I think the measurement events are the “more real”: they constitute our concrete world while wave functions are the abstract possibility space available to be actualized by measurements (they are “real”, too, but not in a concrete sense).
2. While rejecting the naïve assumption that the wave function represents something real, Mohrhoff does want to find an objective description of reality which doesn’t appeal to consciousness. QM gives the probability distribution for unperformed measurements. It is a mistake to see these as subjective probabilities. They are objective probabilities.
I agree with this to an extent: I don’t see full-blown human consciousness as the sole avenue to measurement, and think natural systems implement measurements ubiquitously. However, in my view, the phenomenon of first-person consciousness is rooted in an experiential quality which is part of all measurement events (in the spirit of panexperientialist proposals such as Whitehead's or Gregg Rosenberg's).
But what is Mohrhoff’s positive proposal? What is “this quantum world”?
Here are some notes I took from his writing with my editorial comments in italics.
1. The world is intrinsically non-local. (Don’t be confused by thinking about the existence of a space-time background of points and instants – we contribute that to the theory, its not intrinsic).
2. Identical particles cannot be distinguished from each other independent of their possession of properties which can be distinguished.
So, these two statements imply that the quantum world cannot be built from the bottom up.
So how is it built? From the top-down.
“What ultimately exists is one. Call it whatever you like. Matter and space both come into being when this enters into (more or less fuzzy) spatial relations with itself…””…the relations are self-relations,”
This sounds like the world possesses a power of self-measurement. This is certainly an interesting rearrangement of the mystery, but I don’t see how it increases our understanding of reality.
Nothing has a property until it is measured (including the property of existing in a space-time continuum). Measurements create their outcomes (it isn’t that these properties are ontologically carried by the wave function between measurements). No measurements/no world.
OK (although I would say the wave function carries properties in their form as possibilities, and they are not created but made concrete when measured).
The macroscopic world is real in a way the microscopic world is not, since the probability of finding macro-objects where classically they should not be is very low. “… we must be allowed to look upon the positions of macroscopic objects – macroscopic positions, for short—as instrinsic, as self-indicating, or as real per se.” “The ‘foundation’ is the macroworld… not the micro-world.” “As philosophers would say, the properties of the quantum domain supervene on the goings-on in the classical domain.”
But the existence of macroscopic objects is just a primitive in this interpretation. This top-down view is equivalent to saying we just can't explain macroscopic events or objects. I find this unsatisfactory. I want to see us build an improved bottom-up explanation of the world, where the raw material is a property dualism matching the properties embedded in the quantum probability space with an “ability to measure” property possessed by natural systems.
Friday, March 24, 2006
Futuristic Links
The Future of Philosophy
Brian Weatherson has an interesting post predicting that the trend toward specialization by academic philosophers will reverse in the future. As an onlooker who reads some philosophy, I’d say this would be a very good thing. My specific suggestion would be a plea for more metaphysics. Too often, it seems to me that metaphysical presuppositions go unexplained or unexamined in the specialized areas.
The Future of Fundamental Physics
As I’ve discussed in previous posts, fundamental physics seems stuck. Here’s Lee Smolin’s latest manifesto which stresses the need for more work on the philosophical foundations of theory. Also, here’s a slide show from John Baez which discusses “Where We Stand Today”. (Hat tip: Peter Woits’ blog).
Brian Weatherson has an interesting post predicting that the trend toward specialization by academic philosophers will reverse in the future. As an onlooker who reads some philosophy, I’d say this would be a very good thing. My specific suggestion would be a plea for more metaphysics. Too often, it seems to me that metaphysical presuppositions go unexplained or unexamined in the specialized areas.
The Future of Fundamental Physics
As I’ve discussed in previous posts, fundamental physics seems stuck. Here’s Lee Smolin’s latest manifesto which stresses the need for more work on the philosophical foundations of theory. Also, here’s a slide show from John Baez which discusses “Where We Stand Today”. (Hat tip: Peter Woits’ blog).
Thursday, March 16, 2006
Quantum Physics and Reality (Again)
I want to address this essay in Tuesday’s New York Times by science writer Dennis Overbye entitled, “Far Out Man. But Is It Quantum Physics?” (available with free registration). The essay correctly criticizes the misuse of physics by fuzzy-minded New Age people. But Overbye also errs in buying into an all-too-common misconception about the implications of Quantum Mechanics (QM).
Overbye begins with a discussion of the recent film “What the Bleep Do We Know!?” (which I have not seen). According to his account, the movie's premise is that QM implies the human mind essentially creates reality, so we should be able to alter and improve it as we like. Overbye traces the inspiration of this idea to Eugene Wigner’s suggestion (which followed on John von Neumann’s formulation of QM) that consciousness is the factor responsible for implementing measurements which collapse the superpositions of quantum states into a particular outcome. This idea has been enthusiastically picked up by the filmmakers and other New Ager’s, who inappropriately extrapolate it into the notion that the mind is somehow in control of reality. This opens the door to idealism, paranormal phenomena, and Deepak Chopra.
So far so good. But then we start running into problems when Overbye contrasts this improper use of physics with what he sees as the sober reality of the situation.
He starts by quoting Columbia’s David Albert as saying “It has been decades since anybody took Wigner’s idea seriously.” First, this is incorrect. There are people who have tried to build on the proposal; first and foremost I would cite Henry Stapp (see post here). Second, I believe the reason the mainstream hasn’t worked on the idea is because they lacked good research programs which had traction on the proposed intersection between consciousness and quantum systems; it is not because the idea has been shown to be wrong, which is the impression Overbye’s quick account leaves the reader. I’m personally skeptical that full-blown consciousness is the trigger for wave function collapse, but this remains an open question.
Next, Overbye misinterprets decoherence theory in this passage: “Many physicists today say the waves that symbolize quantum possibilities are so fragile they collapse with the slightest encounter with their environment. Conscious observers are not needed.” I’m sympathetic here since I made the same mistake for years. While I think we can legitimately infer from modern quantum theory and experimental results that natural systems ubiquitously implement measurements all around us, that is not what decoherence theory has shown. Decoherence describes how the interaction of a quantum system with the environment leads to a suppression of interference effects; rather than provide for an objective collapse, it still leaves a ‘mixture’ of states which prevails until we conduct a measurement (see this post for further discussion). The measurement problem remains. (Physicists also continue to explore explicit collapse models, but I think it's fair to say these remain problematic.)
Here’s Overbye’s bottom line:
“In other words, reality is out of our control. It’s all atoms and the void, as Democritus said so long ago. Indeed, some physicists say the most essential and independent characteristic of reality, whatever that is, is randomness. It’s a casino universe.”
This is a very common perspective, among scientists, philosophers and laypeople alike. They take the lesson of QM as being that the strictly deterministic clockwork metaphysics implied by classical physics should be simply overlaid with randomness. But regardless of the details, they assume that a worldview of materialism/physicalism which safely ignores the quantum measurement problem remains the correct stance.
I believe this is wrong. One cannot ignore that the reality implied by QM consists of both deterministically evolving quantum waves and the measurement events which give rise to the concrete phenomena of the macroscopic world. Measurement events remain unexplained within present-day physics. But I conclude the metaphysics necessary for a solution must be richer than physicalism. A property dualism where the ability to measure is an additional aspect of reality is needed (perhaps this could be incorporated into a version of neutral monism, too). And the proposal that this (likely ubiquitous) property and the emergent phenomena of life and consciousness are essentially linked is alive and well. It’s a shame the New Age antics seem to have raised a credibility hurdle for serious consideration of this view.
Overbye begins with a discussion of the recent film “What the Bleep Do We Know!?” (which I have not seen). According to his account, the movie's premise is that QM implies the human mind essentially creates reality, so we should be able to alter and improve it as we like. Overbye traces the inspiration of this idea to Eugene Wigner’s suggestion (which followed on John von Neumann’s formulation of QM) that consciousness is the factor responsible for implementing measurements which collapse the superpositions of quantum states into a particular outcome. This idea has been enthusiastically picked up by the filmmakers and other New Ager’s, who inappropriately extrapolate it into the notion that the mind is somehow in control of reality. This opens the door to idealism, paranormal phenomena, and Deepak Chopra.
So far so good. But then we start running into problems when Overbye contrasts this improper use of physics with what he sees as the sober reality of the situation.
He starts by quoting Columbia’s David Albert as saying “It has been decades since anybody took Wigner’s idea seriously.” First, this is incorrect. There are people who have tried to build on the proposal; first and foremost I would cite Henry Stapp (see post here). Second, I believe the reason the mainstream hasn’t worked on the idea is because they lacked good research programs which had traction on the proposed intersection between consciousness and quantum systems; it is not because the idea has been shown to be wrong, which is the impression Overbye’s quick account leaves the reader. I’m personally skeptical that full-blown consciousness is the trigger for wave function collapse, but this remains an open question.
Next, Overbye misinterprets decoherence theory in this passage: “Many physicists today say the waves that symbolize quantum possibilities are so fragile they collapse with the slightest encounter with their environment. Conscious observers are not needed.” I’m sympathetic here since I made the same mistake for years. While I think we can legitimately infer from modern quantum theory and experimental results that natural systems ubiquitously implement measurements all around us, that is not what decoherence theory has shown. Decoherence describes how the interaction of a quantum system with the environment leads to a suppression of interference effects; rather than provide for an objective collapse, it still leaves a ‘mixture’ of states which prevails until we conduct a measurement (see this post for further discussion). The measurement problem remains. (Physicists also continue to explore explicit collapse models, but I think it's fair to say these remain problematic.)
Here’s Overbye’s bottom line:
“In other words, reality is out of our control. It’s all atoms and the void, as Democritus said so long ago. Indeed, some physicists say the most essential and independent characteristic of reality, whatever that is, is randomness. It’s a casino universe.”
This is a very common perspective, among scientists, philosophers and laypeople alike. They take the lesson of QM as being that the strictly deterministic clockwork metaphysics implied by classical physics should be simply overlaid with randomness. But regardless of the details, they assume that a worldview of materialism/physicalism which safely ignores the quantum measurement problem remains the correct stance.
I believe this is wrong. One cannot ignore that the reality implied by QM consists of both deterministically evolving quantum waves and the measurement events which give rise to the concrete phenomena of the macroscopic world. Measurement events remain unexplained within present-day physics. But I conclude the metaphysics necessary for a solution must be richer than physicalism. A property dualism where the ability to measure is an additional aspect of reality is needed (perhaps this could be incorporated into a version of neutral monism, too). And the proposal that this (likely ubiquitous) property and the emergent phenomena of life and consciousness are essentially linked is alive and well. It’s a shame the New Age antics seem to have raised a credibility hurdle for serious consideration of this view.
Monday, March 13, 2006
Environmentalism Talks at Swarthmore
Here's a plug for an upcoming "Public Issues Forum" (2 lectures plus discussion) being sponsored by the Board of Governors of the Greater Philadelphia Philosophy Consortium:
APPROACHES TO ENVIRONMENTALISM
1:00 to 5:00 pm
Saturday, March 25
Science Center 199
Swarthmore College
Free and Open to the Public, followed by a reception with light refreshments
Speakers:
Mark Sagoff
Institute for Philosophy and Public Policy, U. of Maryland
Talk: "The Artist or the Watchmaker: Two Approaches to Environmentalism"
David Macauley
Dept. of Philosophy, Penn State
Talk: "Re-placing Environmental Philosophy: Walking as a Critical Practice"
Directions to Swarthmore below the fold
Driving Directions To Swarthmore College:
Swarthmore College is located 11 miles southwest of the city of Philadelphia in the borough of Swarthmore, Pennsylvania.
Telephone:
The automated campus directions hotline: (610) 328-8001
The main campus number: (610) 328-8000
Address:
Swarthmore College
500 College Avenue
Swarthmore, PA 19081
Directions:
>From the North (New Jersey Turnpike or I-95)
Take the New Jersey Turnpike to Exit 3 and follow the signs to the Walt Whitman Bridge. Take I-95 South, pass Philadelphia International Airport and continue to exit 7, I-476 North/Plymouth Meeting. Take I-476 North to Exit 3, Media/Swarthmore. At bottom of exit ramp, follow sign for Swarthmore by turning right onto Baltimore Pike. (See below for ". . . the rest of the way.")
From the South
Follow I-95 North to Exit 7 (in Pennsylvania), I-476 North/Plymouth Meeting. Take I-476 to Exit 3, Media/Swarthmore. At the bottom of the exit ramp, follow the sign for Swarthmore by turning right onto Baltimore Pike. (See below for ". . . the rest of the way.")
From the East (via the Pennsylvania Turnpike)
>From Exit 333, Norristown, follow signs for I-476 South. Stay on I-476 approximately 17 miles to Exit 3, Media/Swarthmore. At the bottom of the exit ramp, follow the signs to Swarthmore by turning left onto Baltimore Pike. (See below for ". . . the rest of the way.")
From the West (via the Pennsylvania Turnpike)
>From Exit 326, Valley Forge, Take I-76 East, Schuykill Expressway, about 4 miles to I-476 South. Take I-476 approximately 12 miles to Exit 3, Media/Swarthmore. At the bottom of the exit ramp, follow the signs to Swarthmore by turning left onto Baltimore Pike. (See below for ". . . the rest of the way.")
From the Airport
Take I-95 South. Continue to exit 7, I-476 North/Plymouth Meeting. Take I-476 North to Exit 3, Media/Swarthmore. At bottom of exit ramp, follow sign for Swarthmore by turning right onto Baltimore Pike. (See below for ". . . the rest of the way.")
". . . the rest of the way"
Stay in right lane and in less than 1/4 mile turn right onto Route 320 South (watch turns on Route 320). Proceed through second light at College Avenue to the first driveway on your right to visitor parking at the Benjamin West House. The Benjamin West House is the College's visitor center and has someone there to hand out maps and directions 24 hours a day.
". . .to the DuPont parking lot" (this is the lot adjacent to the Science Center)
Follow the directions under "the rest of the way" but instead of passing through the second light, turn right onto College Avenue. On College Avenue take your first right onto Cedar Lane. At the next stop sign turn left onto Elm Avenue. Before the next stop sign a driveway flanked by stone pillars will appear on your left. Turn there onto Whittier Place and follow it to DuPont parking lot on the right.
APPROACHES TO ENVIRONMENTALISM
1:00 to 5:00 pm
Saturday, March 25
Science Center 199
Swarthmore College
Free and Open to the Public, followed by a reception with light refreshments
Speakers:
Mark Sagoff
Institute for Philosophy and Public Policy, U. of Maryland
Talk: "The Artist or the Watchmaker: Two Approaches to Environmentalism"
David Macauley
Dept. of Philosophy, Penn State
Talk: "Re-placing Environmental Philosophy: Walking as a Critical Practice"
Directions to Swarthmore below the fold
Driving Directions To Swarthmore College:
Swarthmore College is located 11 miles southwest of the city of Philadelphia in the borough of Swarthmore, Pennsylvania.
Telephone:
The automated campus directions hotline: (610) 328-8001
The main campus number: (610) 328-8000
Address:
Swarthmore College
500 College Avenue
Swarthmore, PA 19081
Directions:
>From the North (New Jersey Turnpike or I-95)
Take the New Jersey Turnpike to Exit 3 and follow the signs to the Walt Whitman Bridge. Take I-95 South, pass Philadelphia International Airport and continue to exit 7, I-476 North/Plymouth Meeting. Take I-476 North to Exit 3, Media/Swarthmore. At bottom of exit ramp, follow sign for Swarthmore by turning right onto Baltimore Pike. (See below for ". . . the rest of the way.")
From the South
Follow I-95 North to Exit 7 (in Pennsylvania), I-476 North/Plymouth Meeting. Take I-476 to Exit 3, Media/Swarthmore. At the bottom of the exit ramp, follow the sign for Swarthmore by turning right onto Baltimore Pike. (See below for ". . . the rest of the way.")
From the East (via the Pennsylvania Turnpike)
>From Exit 333, Norristown, follow signs for I-476 South. Stay on I-476 approximately 17 miles to Exit 3, Media/Swarthmore. At the bottom of the exit ramp, follow the signs to Swarthmore by turning left onto Baltimore Pike. (See below for ". . . the rest of the way.")
From the West (via the Pennsylvania Turnpike)
>From Exit 326, Valley Forge, Take I-76 East, Schuykill Expressway, about 4 miles to I-476 South. Take I-476 approximately 12 miles to Exit 3, Media/Swarthmore. At the bottom of the exit ramp, follow the signs to Swarthmore by turning left onto Baltimore Pike. (See below for ". . . the rest of the way.")
From the Airport
Take I-95 South. Continue to exit 7, I-476 North/Plymouth Meeting. Take I-476 North to Exit 3, Media/Swarthmore. At bottom of exit ramp, follow sign for Swarthmore by turning right onto Baltimore Pike. (See below for ". . . the rest of the way.")
". . . the rest of the way"
Stay in right lane and in less than 1/4 mile turn right onto Route 320 South (watch turns on Route 320). Proceed through second light at College Avenue to the first driveway on your right to visitor parking at the Benjamin West House. The Benjamin West House is the College's visitor center and has someone there to hand out maps and directions 24 hours a day.
". . .to the DuPont parking lot" (this is the lot adjacent to the Science Center)
Follow the directions under "the rest of the way" but instead of passing through the second light, turn right onto College Avenue. On College Avenue take your first right onto Cedar Lane. At the next stop sign turn left onto Elm Avenue. Before the next stop sign a driveway flanked by stone pillars will appear on your left. Turn there onto Whittier Place and follow it to DuPont parking lot on the right.
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