A few posts ago I pointed out how Daryl Bem’s Feeling the Future paper (experiments that seem to show the future changing the present) could have been more persuasive. This post is the other side of my critique. I’ll explain why the results are more persuasive than Bem and commentators have said.
If this research is correct, I told my students, you can study for a test not only before but also after you take it. Studying after is better than studying before because you would only need to study what was on the test. And there are reasons to believe the research that Bem didn’t mention:
First, the history of electricity. Electricity, now incredibly important, was once nearly invisible. Remember Galvani? During a frog dissection, an assistant touched an exposed leg-muscle nerve with a static-electricity-charged scalpel. The leg twitched. This tiny accident made all the difference. Galvani studied what had happened. He soon discovered that two different metals in contact generated electricity. This led to the first batteries. With a steady source of electricity, we could learn about it.
The methodological lesson is that the nervous system is (a) unusually sensitive to the environment and (b) easy to “read”. You could touch a static-charged knife to many things: a plant, cloth, a piece of metal, a piece of wood. No doubt this had happened countless times before Galvani. The static electricity changed all of them (plant, etc.) but these changes led nowhere because they were too small to see. In contrast, the effect of static electricity on the nervous system was easy to see. It was amplified by the neuro-muscular junction and the muscle. Measuring the effect of electricity on nerves turned out to be the best way to study it, at first.
My self-experimentation takes advantage of the sensitivity of the brain to the environment. Mostly I study stuff controlled by the brain, such as sleep, weight, and arithmetic speed. Because the brain changes quickly and the changes are easy to detect (via behavior), I can do short convincing experiments. People who study health in other ways have to do much slower and more difficult experiments. For example, bones change slowly in response to dietary changes. Other parts of our body, such as the liver, are much harder to measure than behavior.
The story of how electricity began to be understood suggests that if the future does affect the present, there will be a period when the best way to study this is by studying behavior. This is what Bem did. We don’t normally think of the brain as good for physics experiments but Galvani showed the truth of this. The brain acts as an enormously sensitive amplifier. For example, Barbara Sakitt did an experiment suggesting that the eye can detect single photons. Bem’s experiments cost essentially nothing. He needed no grant. For a physicist to build a detector that detects future effects on the present without involving the brain will surely be more expensive and more difficult, just as it was so much easier for Galvani to use frog legs than build a electricity detector not involving the nervous system.
Second, the history of psi research. Unfortunately Bem omitted even a brief summary from his article. Experiments similar to Bem’s have been going on for decades. In the 1980s, I visited a lab near Princeton doing such experiments. I haven’t studied this research but as far as I know they have repeatedly reported small effects. This is what has kept them going — or at least I cannot rule out this explanation for why it has lasted so long. The alchemists pursued fruitless research a long time but I am unaware they reported small successes. Bem used his knowledge of mainstream psychology (e.g., priming) to design much more sensitive experiments. So it makes sense that these weak effects would become more detectable.
Third, gravity/time symmetry. Bem says we see no signs of the future affecting the present in everyday life. I am less sure. The effects of gravity and time reversal (time going backwards) are remarkably similar. If you watch the same video played forwards and backwards you can tell which is forward (correct) and which is time-reversed: In the time-reversed version, impossible things happen. A man slowly drinks coffee. Correct version: the level of coffee in his cup slowly gets lower, as the coffee goes into his mouth. Time-reversed version: the level of coffee in his cup slowly gets higher, as the coffee comes out of his mouth into the cup. That’s impossible! You can spit again and again into a cup, sure, but you can’t spit pure coffee into a cup. You can’t unmix the coffee from the rest of the liquid in your mouth.
Imagine two billiard balls on a frictionless perfectly flat pool table. They are together in the center. Touching, but not held together. A video of the balls would show them slowly moving apart in response to random disturbances. They move down a probability gradient: Further apart is more likely than close together. This is why a sodium pump is needed to keep enough sodium in cells: because the difference in concentration (more sodium within a cell) makes diffusion out of the cell more likely than diffusion into the cell.
Now we do something different: we randomly and independently place both balls on the table. The placement of one has no effect on the placement of the other. Almost surely they will not be touching. Then we start filming. And a funny thing happens: the balls move closer and closer together! The opposite of the first film, where they slowly drifted apart. They are drifting closer and closer together because they are so heavy that the gravitational attraction is larger than the random forces (e.g., air molecules) in the situation. The second film run backwards looks exactly like the first film run forward! In this way the force of gravity causes time to go backwards. It causes seemingly less-probable events to be more probable than seemingly more-probable events. Rather than have two concepts (force of gravity, passage of time) perhaps we only need one.
I will write more about this later. The simple point is that the effects of gravity are very similar, perhaps identical, to time moving backwards. The force of gravity is obvious and the similarity to backwards time unexplained. Given this failure to explain something easy to see, we shouldn’t be sure we know if the future can visibly affect the present. If time goes backwards to some extent (measured by the force of gravity) then to some extent the future has happened and we know something about it. The more we know about it, the better we can choose to study for a test by studying just the items that will appear on it.
I always say that love at first sight is a result of memories of the future.
That line has got me laid a few times!
The Princeton lab shut down a few years ago.
If you start with a random distribution of particles, running the laws of physics forward or backwards will both look “normal”. It is only after the simulation has run for a period that reversing the time direction makes it look funny. But that effect holds for both (i) starting with +t, and reversing so the equations use -t, and (ii) the opposite, starting with -t, and reversing so the equations use +t. In both cases, the reversed simulation starts to look normal again when you pass the point of the initial distribution.
This is due to the fact that running the simulation (with +t or -t) creates information that is not random (but reflecting physical law). The issue is not time direction, but information.
The separation of balls due to random fluctuations is not the mirror image of gravity, and so I’m not following what you are saying, but look forward to your posts on this.
Henrico, that’s a nice way of looking at it. Suppose there are just two particles in an enclosed space and the only important force is the force of gravity. When you run time forward, the two particles move closer, due to attraction. When you run time backward, they move further apart, due to repulsion (gravity in reverse). In the second case, however, the increase in information (predictability of location) is very slight because the particles are already far apart and are at random locations. Those locations become only slightly less random if the enclosure is large enough.
More concretely if you have a bunch of randomly-placed particles in an enclosed space and you run time backwards with just gravity as a repulsive force they will appear to be moving randomly, as far as I can tell. The build up of information is far clearer when time goes forward. Then gravity will cause them to clump together. Their locations will become perfectly correlated.
In other words, I am not so sure the operation of gravity causes information (predictability of location) to increase when time runs backward. If information is defined as correlation of location, then with two particles, yes, they become negatively correlated due to repulsion. But as the number of particles increases the effect — increase in negative correlation due to repulsion — becomes weaker and weaker.
Entropy is the tendency for a system to move from order to disorder due to the random disturbances you mentioned in the ball example. The force of gravity can counteract entropy…otherwise, for example, the planets in our solar system would not be orbiting around the sun, they’d be moving off into the cosmos.
If the balls were heavy enough to exert gravitational pull on each other and move together, they would be using the force of gravity to overcome the force of entropy. If you filmed this happening, then played it in reverse, it would look like ‘time in reverse’ but the reverse film would be an impossibility in reality unless you put in some sort of energy to make it happen.
I.e., only one of the directions happens spontaneously (depending on which force is bigger), and that is the direction which corresponds with time moving forward.
Also looking forward to the point of all this….
I tend to agree with Henrico on the gravity/time symmetry…
The example of the billiard balls is not actually one case being run back and forth in time; it’s two non-equivalent cases. Case 1 involved the air molecules being more powerful than gravity, and pushing the balls apart as time moves forward. Case 2 involved gravity being more powerful than air molecules and pulling the balls together as time moves forward. If you run Case 1 “backward” (start the balls apart and run time backwards) the air molecules will not push the balls together, they will continue to move the balls around randomly. If you run Case 2 backward (start the balls together and run time backwards) gravity will hold the balls together. In Case 1 gravity is explicitly weaker than the air molecules, in Case 2 gravity is explicitly stronger. In either case there is no gravity/time symmetry, only the special situation where you have “Case 1 rules” (gravity weaker than air) as time moves forward and “Case 2 rules” (gravity stronger than air) as time moves backward.
I think it’s more helpful to think of time as a dimension (length, width, depth, time…) and gravity as a force (gravity, electromagnetism, lift, drag…). Events are caused by forces and measured relative to dimensions. Some events are conservative in time and space, tossing a ball in the air for example, and there is force-force symmetry IN time with those events (gravity is symmetrical, in time, with the projectile force sending the ball into the air). Some events are non-conservative in time, like the “drinking coffee” example, and so in those instances there is no force-force symmetry in time.
This is a very interesting line of thought and I’m looking forward to the rest of the posts, but I think there is a lot more work to do to establish the validity of a time/gravity symmetry. Or maybe I’m missing a subtler point that someone can point out…
“The point of all this” . . . just non-obvious reasons to believe the Bem results, which are basically well-done creative experimental psychology. Not the beginning of coverage of psi experiments.
Sorry…by ‘the point of all this’ I meant I don’t see the connection between the billiard ball thought experiment (requires untrue assumption that the balls exert enough gravitational force on each other to pull them together, overcoming the opposing air movements) and the Bem experiments which produced real effects without any untrue assumptions being made.
But I think you’re trying to say: the Bem experiments produced real effects, and these results might be demonstrating that precognition is possible…so, let’s think about some other reasons to believe that precognition is possible. While my way of looking at it is: the Bem experiments produced real effects, what real conditions caused these effects to happen.
CTB, yes, that’s true. I’m trying to say why Bem’s experiments should not be quickly dismissed. Galvani’s experiments showed how psychology (or at least study of the nervous system) could be helpful to physics. If the future can affect the present that is new physics. Before Galvani, people knew about static electricity. They just couldn’t study it well. It was just a strange thing. I think everyone knows that gravity has an ordering effect (things in different places are drawn to the same place) and the passage of time has a disordering effect, but what to make of that opposition, if anything, hasn’t been clear. It is just a strange thing. Perhaps there is some relation to Bem’s results, just as static electricity and other easily-noticed phenomena (such as lightning) turned out to be related to Galvani’s results.
Joe and Henrico, thank you for your comments. You make good points. I hope to discuss this with a physicist….