In the aftermath of the dispiriting comments following last week’s post on the Parapsychological Association, it seems worth spelling out in detail the claim that parapsychological phenomena are inconsistent with the known laws of physics. The main point here is that, while there are certainly many things that modern science does not understand, there are also many things that it does understand, and those things simply do not allow for telekinesis, telepathy, etc. Which is not to say that we can prove those things aren’t real. We can’t, but that is a completely worthless statement, as science never proves anything; that’s simply not how science works. Rather, it accumulates empirical evidence for or against various hypotheses. If we can show that psychic phenomena are incompatible with the laws of physics we currently understand, then our task is to balance the relative plausibility of “some folks have fallen prey to sloppy research, unreliable testimony, confirmation bias, and wishful thinking” against “the laws of physics that have been tested by an enormous number of rigorous and high-precision experiments over the course of many years are plain wrong in some tangible macroscopic way, and nobody ever noticed.”
The crucial concept here is that, in the modern framework of fundamental physics, not only do we know certain things, but we have a very precise understanding of the limits of our reliable knowledge. We understand, in other words, that while surprises will undoubtedly arise (as scientists, that’s what we all hope for), there are certain classes of experiments that are guaranteed not to give exciting results — essentially because the same or equivalent experiments have already been performed.
A simple example is provided by Newton’s law of gravity, the famous inverse-square law. It’s a pretty successful law of physics, good enough to get astronauts to the Moon and back. But it’s certainly not absolutely true; in fact, we already know that it breaks down, due to corrections from general relativity. Nevertheless, there is a regime in which Newtonian gravity is an effective approximation, good at least to a well-defined accuracy. We can say with confidence that if you are interested in the force due to gravity between two objects separated by a certain distance, with certain masses, Newton’s theory gives the right answer to a certain precision. At large distances and high precisions, the domain of validity is formalized by the Parameterized Post-Newtonian formalism. There is a denumerable set of ways in which the motion of test particles can deviate from Newtonian gravity (as well as from general relativity), and we can tell you what the limits are on each of them. At small distances, the inverse-square behavior of the gravitational force law can certainly break down; but we can tell you exactly the scale above which it will not break down (about a tenth of a millimeter). We can also quantify how well this knowledge extends to different kinds of materials; we know very well that Newton’s law works for ordinary matter, but the precision for dark matter is understandably not nearly as good.
This knowledge has consequences. If we discover a new asteroid headed toward Earth, we can reliably use Newtonian gravity to predict its future orbit. From a rigorous point of view, someone could say “But how do you know that Newtonian gravity works in this particular case? It hasn’t been tested for that specific asteroid!” And that is true, because science never proves anything. But it’s not worth worrying about, and anyone making that suggestion would not be taken seriously.
As with asteroids, so with human beings. We are creatures of the universe, subject to the same laws of physics as everything else. As everyone knows, there are many things we don’t understand about biology and neuroscience, not to mention the ultimate laws of physics. But there are many things that we do understand, and only the most basic features of quantum field theory suffice to definitively rule out the idea that we can influence objects from a distance through the workings of pure thought.
The simplest example is telekinesis, the ability to remotely move an object using only psychic powers. For definitiveness, let’s consider the power of spoon-bending, claimed not only by Uri Geller but by author and climate skeptic Michael Crichton.
What do the laws of physics have to say about spoon-bending? Below the fold, we go through the logic.
- Spoons are made of ordinary matter.
This sounds uncontroversial, but is worth explaining. Spoons are made of atoms, and we know what atoms are made of — electrons bound by photons to an atomic nucleus, which in turn consists of protons and neutrons, which in turn are made of quarks held together by gluons. Five species of particles total: up and down quarks, gluons, photons, electrons. That’s it.
There is no room for extra kinds of mysterious particles clinging, aura-like, to the matter in a spoon. That’s because we know how particles behave. If there were some other kind of particle in the spoon, it would have to interact with the ordinary matter we know is there — otherwise it wouldn’t stick, it would just zip right through, as neutrinos zip right through the Earth nearly undisturbed. And if there were a kind of particle that interacted with the ordinary particles in the spoon strongly enough to stick to the spoon, we could easily make it in experiments. The rules of quantum field theory directly relate the interaction rates of particles to the ease with which we can create them in the lab, given enough energy. And we know exactly how much energy is available in a spoon; we know the masses of the atoms, and the kinetic energy of thermal motions within the metal. Taken together, we can say without any fear of making a mistake that any new particles that might exist within a spoon would have been detected in experiments long ago.
Again: imagine you have invented a new kind of particle relevant to the dynamics of spoons. Tell me its mass, and its interactions with ordinary matter. If it’s too heavy or interacts too weakly, it can’t be created or captured. If it is sufficiently light and strongly interacting, it will have been created and captured many times over in experiments we have already done. There is no middle ground. We completely understand the regime of spoons, notwithstanding what you heard in The Matrix.
- Matter interacts through forces.
We’ve known for a long time that the way to move matter is to exert a force on it — Newton’s Law, F=ma, is at least the second most famous equation in physics. In the context of quantum field theory, we know precisely how forces arise: through the exchange of quantum fields. We know that only two kinds of fields exist: bosons and fermions. We know that macroscopic forces only arise from the exchange of bosons, not of fermions; the exclusion principle prohibits fermions from piling up in the same state to create a coherent long-range force field. And, perhaps most importantly, we know what forces can couple to: the properties of the matter fields that constitute an object. These properties include location, mass, spin, and various “charges” such as electric charge or baryon number.
This is where the previous point comes in. Spoons are just a certain arrangement of five kinds of elementary particles — up and down quarks, gluons, electrons, and photons. So if there is going to be a force that moves around a spoon, it’s going to have to couple to those particles. Once you tell me how many electrons etc. there are in the spoon, and the arrangement of their positions and spins, we can say with confidence how any particular kind of force will influence the spoon; no further information is required.
- There are only two long-range forces strong enough to influence macroscopic objects — electromagnetism and gravity.
Of course, we have worked hard to discover different forces in nature, and so far we have identified four: gravitation, electromagnetism, and the strong and weak nuclear forces. But the nuclear forces are very short-range, smaller than the diameter of an atom. Gravitation and electromagnetism are the only detectable forces that propagate over longer distances.
Could either gravitation or electromagnetism be responsible for bending spoons? No. In the case of electromagnetism, it would be laughably easy to detect the kind of fields necessary to exert enough force to influence a spoon. Not to mention that the human brain is not constructed to generate or focus such fields. But the real point is that, if it were electromagnetic fields doing the spoon-bending, it would be very very noticeable. (And the focus would be on influencing magnets and circuits, not on bending spoons.)
In the case of gravitation, the fields are just too weak. Gravity accumulates in proportion to the mass of the source, so the arrangement of particles inside your brain will have a much smaller gravitational effect than just the location of your head — and that’s far too feeble to move spoons around. A bowling ball would be more efficient, and most people would agree that moving a bowling ball past a spoon has a negligible effect.
Could there be a new force, as yet undetected by modern science? Of course! I’ve proposed them myself. Physicists are by no means closed-minded about such possibilities; they are very excited by them. But they also take seriously the experimental limits. And those limits show unambiguously that any such new force must either be very short-range (less than a millimeter), or much weaker than gravity, which is an awfully weak force.
The point is that such forces are characterized by three things: their range, their strength, and their source (what they couple to). As discussed above, we know what the possible sources are that are relevant to spoons: quarks, gluons, photons, electrons. So all we have to do is a set of experiments that look for forces between different combinations of those particles. And these experiments have been done! The answer is: any new forces that might be lurking out there are either (far) too short-range to effect everyday objects, or (far) too weak to have readily observable effects.
Here is a plot of the current limits on such forces, from the Eot-Wash group at Julianne’s home institution. This particular plot is for forces that couple to the total number of protons plus neutrons; similar plots exist for other possible sources. The horizontal axis is the range of the force; it ranges from about a millimeter to ten billion kilometers. The vertical axis is the strength of the force, and the region above the colored lines has been excluded by one or more experiments. On meter-sized scales, relevant to bending a spoon with your mind, the strongest possible allowed new force would be about one billionth the strength of gravity. And remember, gravity is far too weak to bend a spoon.
That’s it. We are done. The deep lesson is that, although science doesn’t know everything, it’s not “anything goes,” either. There are well-defined regimes of physical phenomena where we do know how things work, full stop. The place to look for new and surprising phenomena is outside those regimes. You don’t need to set up elaborate double-blind protocols to pass judgment on the abilities of purported psychics. Our knowledge of the laws of physics rules them out. Speculations to the contrary are not the provenance of bold visionaries, they are the dreams of crackpots.
A similar line of reasoning would apply to telepathy or other parapsychological phenomena. It’s a little bit less cut and dried, because in the case of telepathy the influence is supposedly traveling between two human brains, rather than between a brain and a spoon. The argument is exactly the same, but there are those who like to pretend that we don’t understand how the laws of physics work inside a human brain. It’s certainly true that there is much we don’t know about thought and consciousness and neuroscience, but the fact remains that we understand the laws of physics in the brain regime perfectly well. To believe otherwise, you would have to imagine that individual electrons obey different laws of physics because they are located in a human brain, rather than in a block of granite. But if you don’t care about violating the laws of physics in regimes where they have been extensively tested, then anything does in fact go.
Some will argue that parapsychology can be just as legitimately “scientific” as paleontology or cosmology, so long as it follows the methodology of scientific inquiry. But that’s a slightly too know-nothing attitude to quite hold up. If parapsychologists followed the methodology of scientific inquiry, they would look what we know about the laws of physics, realize that their purported subject of study had already been ruled out, and within thirty seconds would declare themselves finished. Anything else is pseudoscience, just as surely as contemporary investigation into astrology, phrenology, or Ptolemaic cosmology. Science is defined by its methods, but it also gets results; and to ignore those results is to violate those methods.
Admittedly, however, it is true that anything is possible, since science never proves anything. It’s certainly possible that the next asteroid that comes along will obey an inverse-cube law of gravity rather than an inverse-square one; we never know for sure, we can only speak in probabilities and likelihoods. Given the above, I would put the probability that some sort of parapsychological phenomenon will turn out to be real at something (substantially) less than a billion to one. We can compare this to the well-established success of particle physics and quantum field theory. The total budget for high-energy physics worldwide is probably a few billion dollars per year. So I would be very happy to support research into parapsychology at the level of a few dollars per year. Heck, I’d even be willing to go as high as twenty dollars per year, just to be safe.
Never let it be said that I am anything other than open-minded.
This kind of post is the reason I read your blog… you have the ability to bring down the complex stuff to support ordinary knowledege. I admit I didn’t fully understand the graph, but I think I can believe you anyway.
But just as your arguments are powerful, so can other arguments have the same power given a good writer and an ill-informed listener, and that happens a lot.
Do you think blogging/teaching is the only way to help the ill-informed be more suspicious of what they believe?
Do you think there’s a certain point in which persons are not going to understand more arguments? Is it bad to give up?
It’s ok to give up on certain people, such as charlatans and preachers- to paraphrase Upton Sinclair, those whose paychecks are dependent on their lack of understanding.
The people who have been fooled by those charlatans and preachers can and must be won over by science, unless you want to just give them up to superstition and let them come back to fight you later (most of the fighting right now is around issues of public health and education. but that bad science education mandated by creationists affects physics education too).
Sean, I’ve been working on an essay called The Atheist’s Guide to Tragedy, and about my frustration trying to explain to a friend/neighbor that the hundreds of dollars she’s spent on Astral Projection classes is a complete waste since it’s not possible.
Since I’m not a scientist, it’s often hard for me to put into words why it’s crap, but this post has helped a lot in how I’ll explain in the future.
And also, it gives me great happiness that I’m not so alone in not believing in magic.
Awesome article. I’m definitely saving a link to it to refer people towards when they point out that science doesn’t know “everything” next time. The probability/cost estimate at the end is just brilliant, though I can’t help thinking that studying parapsychology to a limited extent could be useful, for the purpose of understanding why so many people believe pseudoscience (but perhaps it’s just psychology in that case?).
I’ve been working on some ideas to try to explain to some friends why Astrology is almost certainly bunk. Going through the fallacious arguments and lack of evidence is useful, but this sort of approach is much more concrete and I’d bet it will make more sense to some of them. Thanks for the ideas.
Sean, posts like this are the reason I love this blog. Like others here in the comments, I am continually frustrated by those who do not understand the limits imposed by well-understood physics. However, while I personally would put the odds at telepathy working at less than a billion to one, I’m inclined to question some of your comments near the end of the article. Obviously telekinesis, astral projection, and some other forms of paranormal activity would require the existence of forces that we know don’t exist, as you say; however, it is known that brain activity created EM-waves. From what I understand, these waves are fairly weak, and difficult to detect even with our sophisticated technology, but nature has beaten us in technological advancement before. Isn’t it possible that some very special people have equally special sensors that allow them to detect and translate these electromagnetic waves into thoughts? Perhaps they would need to be in direct contact to detect them, and I think it is 100% safe to assume that they couldn’t detect them over any appreciable distance, but in this theory of telepathy, no mystical new forces of nature are needed – just the detection of weak electromagnetic waves. Again, I’m NOT saying I believe those who claim they can do this, just asking if it isn’t outside the realm of known physics? Am I wrong? I would love it if I am.
Chris, you’re right, and that’s why the telepathy case is less straightforward. Brains are made of charged particles, and in principle they could create and detect electromagnetic signals — radios and walkie-talkies do it all the time!
But that’s just the point — they are really easy to detect. Setting up a radio receiver would be a much better way to test the phenomenon than looking at abstract symbols on cards behind a screen. And when we get into the details, the brain isn’t really set up to transmit very strong waves; its functioning is more chemical than electromagnetic. There are many other sources all around us that are creating much stronger electromagnetic waves, at all sorts of frequencies.
Still, at the level of the brain itself, there is much we don’t understand, and I would certainly support research into the role of electromagnetic fields in the brain. It would fall under “neuroscience,” of course, not “parapsychology.”
Fantastically well written. Coincidentally, your post here is somewhat related to one at Bad Astronomy today.
Pingback: Two excellent contributions to the “pseudoscience FAQ” | Geoff Arnold
Howdy CV,
There is another approach to the question of whether or not such phenomena exist. While I appreciate (and enjoy) Sean’s argument, there is a more basic, perhaps easier to appreciate, starting point for many people. While I am very happy to start from very basic principles, it’s often easier to convince people with much simpler and more direct arguments/evidence.
Suppose the possibility of an outside, here-to-fore unseen, unknown interaction mechanism that is responsible for telekinesis. Many people without a firm knowledge of what we already understand about nature will find this a familiar starting point. Without seeking to construct a possible method or mechanism, it is fairly simple to test for its presence in a direct fashion. This does not require the budget of the LHC or the APS or even much of any budget. Some modest money, time and effort is all that is necessary to perform such a test. And in fact, many people have done just such experiments in the past.
The simple fact is that, in all reliable, controlled tests, no telekinesis has been observed. In the cases where there was a “positive” the outcome was not repeatable at different times (anyone remember Carson’s excellent show where Uri Geller attempted to perform?). As such, with no repeatability, with no independent verifiable evidence, those reports of positive tests must be miscounted. It is entirely possible, even for career scientists, to either make a mistake (often through a preconception of the outcome and improper control) or to be fooled (human subjects are not entirely known to be completely honest, Uri Geller for instance). Give Martin Gardner, James Randi or Carl Sagan a good read as a starting point for such information.
Anyhow, people have gone to look for such phenomena directly and never found any consistent, reliable, reproducible positive outcome. In a total absence of observable evidence and a long list of negatives, we are left with the conclusion that it just doesn’t exist. Further testing of the same phenomena, under the same conditions (I predict!), will produce the same results (and hence not tell us anything new, nor be worth serious effort). If there was any real evidence of “paranormal” phenomena, then of course it could be included within the rubric of science. But as it stands now (and has for some time), it just doesn’t hold water and therefore isn’t science. Even without a well phrased argument of how it doesn’t fit with our current understanding of nature, the simple repeated experimental failure should be enough to remove it from science (and hence the AAAS).
If such tests had not been previously performed, it would be very good to consider your argument before attempting to pursue such a course of research. Especially when considering the question of spending money and effort on something completely off the envelope of current understanding. Anyhow, the simple, “people have looked for it in the past and not reliably seen it” statement, while a bit dry, may find readier acceptance by some people.
best wishes
Michael
(apologies if my statement is a bit scattered. I’m polishing/cleaning samples with only scattered 5 minute spots of time between cycles to write this)
I used to think that Scientists should have an open mind about testing paranormal phenomena, until I read the following passage from Steven Weinberg, and suddenly I understood why they should not:
“When the Spanish settlers in Mexico began in the sixteenth century to push northward into the country known as Texas, they were led on by rumors of cities of gold, the seven cities of Cibola. At the time that was not so unreasonable. Few Europeans had been to Texas, and for all anyone knew it might contain any number of wonders. But suppose that someone today reported evidence that there are seven golden cities somewhere in modern Texas. Would you open-mindedly recommend mounting an expedition to search every corner of the state between the Red River and the Rio Grande to look for these cities? I think you would make the judgment that we already know so much about Texas, so much of it has been explored and settled, that it is simply not worthwhile to look for the mysterious golden cities. In the same way, our discovery of the connected and convergent pattern of scientific explanations has done the very great service of teaching us that there is no room in nature for astrology or telekinesis or creationism or other superstitions.”
That’s from the end of the second chapter of “Dreams of a Final Theory”
Man, that’s a lot of words.
All I’d say is “Because it’s all a bunch of crap! Because I said so!”
Hi Sean,
Nice post, very clearly written.
I understand what you are saying with ‘science never proves anything’ with which you seem to refer to ‘real world objects’ (with all the clutter that comes with the word ‘reality’), but you have thereby declared you don’t consider mathematics to be a science. Which I find admittedly somewhat inappropriate. ‘Scientia’ (Lat) means simply ‘knowledge’ and is not necessarily bound to knowledge about meteorites or spoons. I would think mathematics qualifies as a science, even if you call this kind of knowledge ‘tautologies’.
Also, I think the matrix spoon isn’t concerned with interactions at all, it rather refers to our fragile notion of reality. The human imagination can make up many scenarios that violate the laws of nature, and reality is never objective, it is just what your brain believes it to be.
Best,
B.
Pay no attention to andy.s
Moving spoons with your mind is (in principle) trivial.
The distance between my mind and the spoon is three feet, but as is well known, the space-time interval between my mind (now) and that same spoon three nanoseconds in the future is 0.
So in a sense, the future spoon and everything in the universe on the forward light-cone is a distance of 0 from my mind. So my mind should (in principle) be be able to wield any force imaginable on the spoon, no matter how short range such a force may be.
Pay no attention to my alter ego.
He gets this way when I forget to take my meds.
Just a matter of time with new tech before we see sht move with the mind. If you could would you let anyone know. Being a lab rat would really suck. We’ve all had it happen to us and laughed it off as being strange. Now think of generations of people thinking and practicing with the mind. Research the spells of the Vatican. The History channel said they have real SHT and real spells said to work, to call on angels. Micheal…
Need moor brain power see what science says to do on Livingwithoutcancer.org!
‘Scientia’ (Lat) means simply ‘knowledge’ and is not necessarily bound to knowledge about meteorites or spoons. I would think mathematics qualifies as a science, even if you call this kind of knowledge ‘tautologies’.
The etymological origin of the word “science” has nothing to do with the current meaning of the English word science; if “science” merely means “knowledge,” then every field of study imaginable is a “science.” Memorizing the capitals of the 50 US states will give you knowledge, but I don’t think anyone would call it a science.
Anyway, I would indeed assert that mathematics is not a science. Science follows the scientific method; mathematics does not.
Chris (#6) – re telepathy:
Thoughts are not some Platonic form floating in space. My thoughts consist of patterns within my brain. Those patterns exist in a unique neural net that grew in accord with DNA instructions and in response to unique personal circumstances (eg, nutrition, training, trauma, infections, etc). So there is no one-to-one mapping of my brain onto yours. The pattern in my brain for ‘rice pudding’ may be very different from your pattern for that concept. So why do some people think that we can ‘read’ the thoughts of others? Even if we knew the appropriate patterns to look for, we would need extremely fine resolution to discern events on a cellular scale. So our existing scientific knowledge seems to indicate that mind-reading is an unlikely event.
But more to the point, no one has yet repeatably demonstrated any ‘psychic’ phenomenon. So for all the billions of words written about such abilities, they appear to be wishful thinking.
Hey, what if the spoon just bent itself coincidentally at the time the performer says so? I mean by some weird extraordinarily unlikely case when the air molecules are all just pushing in the same direction to bend the spoon? Just a thought.
Thank you! (Both literally, and in the current way that people ackowledge support of their own opinions.) And yet, Freeman Dyson, whom I otherwise respect, says this in “The Scientist As Rebel” (hope I am not violating any Fair Use laws):
From a review of “Debunked: ESP, Telekinesis, and other Psuedoscience”, by Charpak and Broch:
… There are strange events which appear to give evidence of supernatural influences operating in everyday life. They are not [always] the result of deliberate fraud or trickery, but only of the laws of probability. The paradoxical feature of the laws of probability is that they make unlikely events happen unexpectedly often. A simple way to state the paradox is Littlewood’s law of miracles. Littlewood … a professional mathematician … defined a miracle as an event which has a special significance when it occurs, [and which] occurs with a probability of one in a million.
Littlewood’s law of miracles states that in the course of a normal person’s life, miracles occur at the rate of roughly one a month. The proof of the law is simple. During the time that we are awake … we hear and see things happening at the rate of about one per second. So the total number of events that happen to us is about … one million per month.
[Discussion of attempts to detect paranormal “abilities” by the Rhine methods and others, “a sorry story”.]
… Charpak and Broch and I agree that attempts to study ESP … have failed. Charpak and Broch say that since ESP and telepathy cannot be studied scientifically, they do not exist. Their conclusion is clear and logical but I do not accept it because I am not a reductionist. I claim that paranormal phenomena may really exist but may not be accessible to scientific investigation. This is a hypothesis. I am not saying that it is true, only that it is tenable, and to my mind plausible.
… One fact that emerges clearly from the stories is that paranormal events occur, if they occur at all, only when people are under stress and experiencing strong emotion.
… I should here declare my personal interest in the matter. One of my grandmothers was a notorious and successful faith healer.
… Whether paranormal phenomena exist or not, the evidence for their existence is corrupted by a vast amount of nonsense and outright fraud.
… A deluge of eloquent letters came in response to this review. Orthodox scientists were outraged because I considered the existence of telepathy to be possible. True believers in telepathy were outraged because I considered its existence to be unproven.
It isn’t just physics that rules out parapsychology. You can also get a lot of mileage out of mere physiology. Consider telepathy. The relative size of the parts of animal brains that process the various sensory modalities are proportionate to the extent to which the organism relies on that sense. Animals that track their prey by smell, for example, have large olfactory lobes. Visual animals such as eagles and hawks have large sections of their brains dedicated to processing information from their eyes. Electric fish, which navigate muddy water by interpreting electric fields, have special sections of the their brains to deal with electrical data. Thing is, there is just no section of the human brain that is a plausible candidate for the organ of telepathy.
20. JimV: quoting Freeman Dyson: “and to my mind plausible.”
So much the worse for Freeman Dyson’s mind.
“Thing is, there is just no section of the human brain that is a plausible candidate for the organ of telepathy.”
One can also argue from an evolution theoretical standpoint. Would it be possible to communicate by telepathy at all, then this would have an obvious positive effect on survival, and it would have been developed by many species. That only a few people would be able to do this, and this barely, just does not make any sense.
I think it’s useful to reserve the word “science” for the particular type of contingent, empirical knowledge about this actual world that we obtain through hypothesis testing, observation, and experiment. The type of logical truths revealed by mathematics (and amenable to proof) seem very different. There are obviously similarities, but the distinction is worth emphasizing — especially because too many people suffer under the misimpression that physics and biology actually do “prove” that certain things are true or false.
One can also argue from an evolution theoretical standpoint.
No, we all would have killed each other if we knew what we were all thinking of each other.
Plus, no poker.