Farewell PEAR Lab -- You were always overripe.

News in the last few weeks that the Princeton Engineering Anomalies Research Lab -- the PEAR Lab -- is shutting down.  The PEAR Lab, run by Dr. Robert Jahn, the former Dean of Engineering, was by no means celebrated at Princeton.  I spent four years there in graduate school and only heard of the Lab during my last year, in Malcolm Browne's science writing class no less, rather than during all those many hours in Jadwin Hall.

Phillip Ball had a nice retrospective on the Lab in last week's Nature entitled, "When research goes PEAR-shaped."  Ball quotes Will Happer, a professor in the Princeton Physics Department and a member of JASON as saying, "I don't believe in anything [Jahn] is doing, but I support his right to do it."  That's pretty charitable, actually, compared with many of the things said about the lab.  Nature continues to pile it on this week, with another piece: "The lab that asked the wrong questions," by Lucy Odling-Smee.

This is the crux of what was wrong with the PEAR Lab.  In that science writing class, Malcolm Browne occasionally brought in people to be "interviewed" by the class, and one day we had someone in from the Lab.  (My recollection is that it was Jahn himself.)  Can't say I was impressed.  But data is data, and they certainly may actually have measured something interesting, however unlikely that may be.  There are many things we can't yet explain about the universe, and maybe Jahn was on to something.

What I found unfortunate, even unpleasant, in the way the data was presented was the context.  Jahn was represented to us not just as an expert in aeronautics, but also in a whole host of other fields, including quantum mechanics.  And we were offered a physical theory "explaining" one experiment, supposedly a quantum mechanical theory.  Here's the problem: that theory, by its very nature, is wrong.  It is inconsistent in its conception and structure with all the rest of quantum mechanics.  The folks in the PEAR Lab were definitely asking the wrong questions, in a very deep physical sense, by which I mean that everything about the way they tried to explain the data I saw was contradicted by modern physics in fundamental ways. 

According to Dr. Jahn, a random process seems to be the vital ingredient for anomalous interactions between consciousness and machines -- coins flipping, balls dropping through a forest of pegs, even electronic random number generators -- which is what led him to speculate about connections between his data and a successful theory in which measurements are probabilistic: quantum mechanics.  In some interpretations of quantum mechanics, the observer and the system observed are both part of a larger closed system.  Indeed, Dr. Jahn and his colleagues believe that quantum mechanics may be just a part of a larger theory that includes phenomena studied in the PEAR Lab.  If this is so, then one would expect the structure of the two theories to be similar.

The theory we were told about was purported to explain how an observer could, by thinking "slower" or "faster", change the period of a large pendulum, something like 2 meters in length, if I recall correctly.  A brief refresher on the relevant classical physics: the period of an ideal pendulum is determined only by its length and the strength of the force of gravity, at least in the case when oscillation amplitudes are small, and not by its mass, or the kind of bearing it is suspended from, or any other factor. Though friction will eventually damp a real pendulum by changing its amplitude, not its period.   

The mechanism by which human consciousness might change the period is not easy to imagine.  The human observer states the intention either to increase or decrease the period, and as the pendulum interrupts photodiodes on each swing the time is recorded.  But whereas a quantum mechanical model requires a probability for the observer to intentionally alter, here the observer is actually trying to intentionally change the period.

Before I go on (and on), you must be asking "Why spend so much time on this?"  Why bother to debunk bad science at all?  Because the universe is full of strange and wonderful things, and we don't yet understand them all.  That's what makes life interesting.  Besides, I like thinking about quantum mechanics.  Back to the story.

Dr. Jahn claimed his data is consistent with the the human subject affecting the damping of the pendulum's oscillation.  Microscopically, friction might be changed by heating or cooling the bearings of the pendulum (which could be tested by carefully measuring the temperature of the bearing during an experiment) causing the atoms in the bearing to move around more or less, a phenomena well understood in statistical mechanics -- and in fact a probabilistic effect.  However, since the operator was not trying to influence this probability distribution, it is not clear how his or her binary intention of changing the period of the pendulum was converted into changing the amount of friction.  Or perhaps the observer was changing the length of the pendulum, or the overall strength of gravity, or even the local coupling of the earth's mass to that of the pendulum.  Still no obvious connection to any distribution.

When asking a question of a quantum mechanical system, or a quantum mechanical question in the parlance of physicists, it must be one which can be phrased in terms of what is called an "operator."  Energy, momentum, and position are all operators and as such provide tools for asking quantum mechanical questions.  The energy operator, for instance, would be used to ask about the average energy of the atoms in the bearing.  To find an analogy to the pendulum we must look in quantum mechanics to something called a harmonic oscillator, which can be imagined as a ball rolling back and forth at the bottom a parabolic bowl.  Two operators used in asking questions about such a system are the raising and lowering operators, which as their names suggest change the energy of a particle and its period of oscillation.

So, for the sake of argument, let's give the PEAR Lab a quantum mechanical operator that works on a macroscopic pendulum.  It might be imagined that a human consciousness is utilizing some sort of raising and lowering operator by intending to increase or decrease the period of oscillation of the pendulum.  Yet the data is fit by assuming the friction in the bearing is changing.  It is simply not consistent with the structure of quantum mechanics to ask one valid question and get the answer to a different valid question.  Furthermore, it is hard to imagine how a more general theory, one subsuming quantum mechanics -- oh, what the hell, let's just call it "magic" -- could account for asking a question of the period of the pendulum with an operator belonging to the "magic" theory but get an answer which is the result of asking a question with the well known and well loved energy operator of quantum mechanics and which could only describe the microscopic state of the bearing.  So there.

Then there is that little thing called the Correspondence Principle, proven correct time and time again, which says that quantum mechanics works for small numbers of atoms.  As the number grows, save in very special, very strange circumstances like Bose-Einstein condensates, your theory must reduce to classical physics.  Which brings us back to the classical model that the period of the pendulum depends only on its length.  Nothing about the bearing, nothing about the observer.  Moreover, the pendulum is big, and the human subject is big.  Many, many atoms.  No quantum mechanics.  Wrong question!

Did you follow all that?  Does your head hurt?  Sometimes quantum mechanics does that, I assure you.  But I suppose "magic" could account for your headache, too.  We must allow for that.  Somehow.  See the PEAR Lab.

Sometimes the exploration of something that seems silly results in important insights, and the rest of the time it is important to keep the human participants of science honest.  That's the way science works.  And science always wins.