This article was originally published Mar 4, 2015
photo by Zeynep Kavalci
In physics, time exists but it has no preferred direction. It can flow forward—the way we experience it each day in our consciousness. Or it can flow backward, as the Queen in Alice in Wonderland lived her own life. But physics formulas function equally well no matter which way time is running.
“The laws governing clockwork going in reverse are the same as those of clockwork going the usual way—the variable merely becomes -t,” writes physiologist and biophysicist Werner R. Loewenstein in Physics in Mind.
This reversibility of time seems to open up a whole realm of possibilities, one of which is the ability of the future to affect the past. Many physicists, such as Richard Feynman and Yakir Aharanov, have speculated that causality is a bidirectional creature, one that feeds on the quantum food known as entanglement.
Quantum physics, though, is a far cry from our everyday world of getting up in the morning and moving forward through time all day long. Some scientists, though, have attempted to find more commonplace examples of retrocausality—such as the ability of the future to affect decisions that we make in the present.
One of these is Cornell psychologist Daryl Bem, who stirred up controversy with a 2011 study published in the Journal of Personality and Social Psychology. In his article, Bem suggested that ordinary people can be changed by experiences that they haven’t had yet—which suggests that the Future is somehow impinging on the Present.
His study consisted of nine separate experiments. In one of them, 100 students were asked to guess which curtain on a computer screen hid a picture, some of which were explicit erotic images. After 100 trials, students who were shown erotic stimuli guessed correctly 53.1 percent of the time, better than guessing at random. (The hit rate of those viewing non-erotic pictures, however, was only 49.8 percent)
“The remarkable finding [we made] is that their physiological responses are observed to occur about two to three seconds prior to the appearance of the picture, even before the computer has decided whether to present a non-arousing or an arousing picture,” Bem told the Cornell Daily Sun.
One possible reason that certain students performed better than chance is that the opportunity to view a steamy picture passed backwards in time more easily. Critics, however, weren’t impressed, claiming that Bem’s methods were flawed. A later attempt to replicate his findings also came up empty.
Bem currently has a paper under review that looks at more examples of people seeming to anticipate future events—or what appears to be the Future bleeding back into the Present. It will take some time for the field of psychology to sort this out, along with its general problems of replicating studies.
In the meantime, quantum physicists continue to ponder retrocausality. However, even if this kind of future influence does exist, it will likely occur only under certain circumstances. That’s because the universe as a whole is tilted toward moving in the forward direction, leading from the highly ordered Big Bang toward a highly disordered future.
“To us believing physicists, the distinction between past, present and future has only the significance of a stubborn illusion.” ~ Albert Einstein
New evidence shows that the key assumption made in the discovery of dark energy is in error
The “fittest” quantum properties make the most copies of themselves.
Reversing history from Galileo's time, it is now the scientists who refuse to look through the telescope.
Recent experiments have put relatively large objects into quantum states, illuminating the processes by which the ordinary world emerges out of the quantum one.
Any theory of quantum gravity is going to have to grapple with some weird time stuff.
What is happening right now? Is your “now” the same as my “now”?
A new proof in computer science also has implications for researchers in quantum mechanics and pure mathematics
Ever wonder how we try to predict the unpredictable? Supercomputers use the power of chaos theory.
In this inspiring talk, the mathematician Edward Frenkel speaks about the beauty and elegance of mathematics
The laws of physics imply that the passage of time is an illusion. To avoid this conclusion, we might have to rethink the reality of infinitely precise numbers.
Please enter your email and we’ll send you instructions to reset your password