“Precognition and the ‘Quantum Handshake’” Threatens Causality. Here I Come to Save the World!

By Dr. Peter C. Lugten

March 2023

Daniel P. Sheehan is Professor of Physics at the University of San Diego with interests including both the potential for gaining work out of thermodynamics second law violations, and retrocausation: the proposition that the future can influence the past. So, he’s unafraid to be an iconoclast. In 2016, remote viewing researchers Dale Graff and Patricia Cyrus investigated whether 33 subjects could make convincing drawings of a photograph that would be published in a distant regional newspaper three days later. Reportedly, 21 of these efforts were subjectively successful (Graff, 2017). It is not the purpose of this paper to evaluate the results of that experiment. The purpose of this paper is to examine the theoretical basis for this precognition experiment that was provided by Professor Sheehan at the “The Science of Consciousness” conference on May 19, 2022 (Sheehan, 2022). Professor Sheehan argued that the Transactional Interpretation of Quantum Mechanics, with its associated “quantum handshake”, explains precognition. This explanation would have the unfortunate side effects of destroying the second law of thermodynamics, indeterminacy in the Universe, and with it, free will. Success of any such retrocausal experiment would overturn our notion of causality, of events being caused by actions preceding them, and mean that we could only point to correlations between activities, not such things as reasons for, and responsibility.   

One of the most controversial mysteries in modern physics is how the quantum-level behavior of subatomic particles, described by Schrodinger’s equation for their wave functions, scales up to the classical physics of experience. In 1986, John G Cramer Jr. at Washington University proposed the Transactional Interpretation of Quantum Mechanics (Cramer, 1986). He published “The Quantum Handshake” in 2016 (Cramer 2016).  Subsequently, he and Caltech physicist Carver Mead investigated how quantum systems become fixed observations through wave function collapse. This is related to quantum decoherence, whereby a system’s quantum nature leaks into the environment. From 2007-2014, Cramer investigated whether quantum nonlocality can be used to send a signal of switchable interference patterns backwards in time (Wikipedia 2023). He discovered that each interference pattern resulted in a superimposed complementary “anti-interference pattern”, which “erases” potential nonlocal signals leaving no perceptible interference pattern. He called this the “show stopper” within quantum formalism (Cramer 2014). Consequently, nature is protected from any possible retrocausal signaling, its consequences and paradoxes. Cramer explained: “The TI does not allow time travel.” In his 2015 retrocausality experiments,  he hoped interference waves would provide evidence for backwards causation but they canceled out. “Nature is sending messages faster than light and backwards in time, but she’s not letting you in on the action. It’s blocked by this process”, he said (Boyle 2020).  

Whereas quantum theory has typically considered the emission of a photon (by an “emitter”) to be a stand-alone event, according to the Transactional Interpretation (TI), it is conjoined with an absorption event (by an “absorber”). (Cramer 2017) The emitter is an atom in an excited state, which after losing a quantum of energy, returns to its ground state, ready to absorb a photon in the future. The absorber is an atom in its ground state. After absorbing a photon, it enters an excited state, ready to emit a future photon. In TI, the transaction occurs in these 4 stages. (1) The emitter, in a quantum event, sends an “Offer Wave” (OW, also called a retarded wave), a time-dependent quantum wave function Ψ (Psi) that spreads, wave-like, through spacetime until it meets an absorber. (2) Any potential absorber (there may be many) responds to the OW, producing an Advanced Confirmation Wave (ACW), the complex conjugate of Ψ, or Ψ* (Psi-star). Being in phase with Psi, the ACW has an amplitude of ΨΨ*. It travels backwards in time, arriving at the emitter simultaneously with the OW emission. In what we might call the reference frame of the photon at light speed, the transaction takes place instantaneously, even if the photon takes billions of years, in our own frame, to reach its target. (3) A stochastic choice (probabilistic, and unpredictable) takes place at the emitter between the multiple ACWs it receives from different potential targets the OW impinged upon, according to the amplitudes of the ACW echoes. (4) Repetition to completion of this process occurs (i.e., multiple wave exchanges) by the emitter and the selected absorber, until all conserved quantities of the quantum event are transferred. The potential quantum event has become real: the “quantum handshake”. At this point, the OW ceases to spread into the world in all directions simultaneously, the wave function has “collapsed”. No other transaction is permitted based on that photon.

A major controversy in quantum physics is the idea that the quintessential quantum event of the wave function collapse is caused by a classical level, consciously observed measuring device. Cramer wrote that all physical processes, including the observer, have equal status. Measurement with its apparatus hasn’t special status except that this measurement happens to connect and provide information to observers (Cramer 2017). The observer-induced “collapse of the wave function” is replaced with an objective, observer-independent quantum process. As University of Maryland physicist Dr. Ruth E. Kastner observed, by treating the absorption of the photon as an actualized part of its emission, TI gives a realist account of the classical world of experience in quantum terms (Kastner 2013). 

Daniel P. Sheehan began his talk discussing the second law of thermodynamics with a list of several experimenters claiming to use the law to violate it. They’ve designed devices to exploit the abundant but high entropy thermal energy of the Earth’s ground, water and air. These drop in temperature and should generate lower entropy energy to perform work. This would create a perpetual cycle, at least for the Earth’s lifetime. Sheehan claims this challenges the second law as explanation for the “arrow of time”, although it’s been challenged on other grounds, for instance, by Professor Richard Muller in “The Physics of Now” (Muller 2016). 

Sheehan demonstrated an example of TI using the star Earendel, 12.9 billion lightyears away in Orion. Earendel emitted an OW that impinged on countless objects before reaching a receptor (absorber) on the Hubble telescope 12.9 billion years later. Each returned an ACW, but, in this case, the Hubble ACW was stochastically “chosen” to complete the transaction, and a photon was absorbed. In his diagram of a lightcone, he depicted the psi/psi*  transaction taking place between the present observer and Earendel. A lightcone can be imagined as a wave stretched along time (the y axis) as its front travels outwards in distance (the x axis) from its origin. Picture a pebble thrown in a pond. As the front wave spreads, it moves upwards and downwards to create the cone (actually hour-glass)-shaped graph. The inside of the hourglass, pointing forwards and backwards in time, is represented by the upper and lower two central segments. They represent the volume of the Universe within which anything can communicate with the observer, limited by the speed of light. The top half is the region of the Universe that can receive light, or slower signals from us, sent now or in the future. The bottom half is the region that may have sent light or slower signals in the past that can reach us now. We can see that Earendel’s signal, a photon, travels toward us from the past along the edge of the cone, because it is traveling on the crest of its own lightspeed wave, constituting the boundary of the light cone. (figure 1)

Professor Sheehan next explained that precognition and remote viewing, such as Cyrus’ experiment, could be explained by future events affecting the observer through retrocausal waves. With the “quantum handshake” creating the present, the OW and ACW are on equal footing, and our future self could send an ACW back in time to our present self, which would respond by sending an OW to the future. Their transaction conveys information but not energy from future to present. Therefore quantum mechanics accounts for precognition when the second law of thermodynamics cannot.   

This implies a quantum mechanism for consciousness. He suggested quantum discord allows preservation of quantum correlations even despite decoherence, so that memories and thoughts can become a decoherence-free subspace. It’s important because, according to Roger Penrose and Stuart Hameroff’s quantum model of consciousness, a sheltered molecular environment is needed where quantum coherence can be prolonged for far longer than any known mechanism allows (Marshall 1989). 

Sheehan and Cyrus have proposed a quantum oracle (or a Time Machine) to send us information from the future (Sheehan 2022). Shehan explained this with a diagram similar to the one below on the left.     

I believe there’s a problem with Sheehan’s cone, on the left. His present self sits where horizontal and vertical axes intersect, in my diagram on the right, on Sunday. His future self, say on Wednesday, is depicted almost half way between the vertical axis (his position Sunday) and the lightcone’s edge. That edge is at a distance photons travel in 3 days, about 16 billion miles. He could be visiting star Wolf 359, 7.8 lightyears away. But the OW of any photon he emitted on Sunday has now almost reached Altair, in Aquila, 16.77 lightyears away on the lightcone’s edge. If he’s to emit an informative ACW to his Sunday self from his Wednesday position, he would have to be somewhere on Wednesday where he could intercept the returning OW. To intercept it, he would have had to leave Earth and reach Altair faster than lightspeed. The diagram on the right, where the top horizontal line represents Wednesday, shows a person at distance z from Sheehan on Sunday emitting an ACW on Wednesday. It intersects with Sheehan’s position on the y axis on Tuesday.  If persons at x on Wednesday want to communicate with Sheehan on Sunday at the same location, they must wait until Wednesday. In other words, if persons want to communicate with Sheehan on Wednesday, then the closer they are to Sheehan’s location, the closer to Wednesday they must wait. Or, alternatively, if Sheehan wished to learn of an event three days in the future, that event must occur 16 lightyears away, at which distance, according to a relativistic rocket traveler, there would be no way to judge which came before or after.

I believe Sheehan’s oracle project is also invalidated by TI theory. For retrocausation to work, the advanced confirmation wave (ACW) would have to be able to carry information from the future back to the present. Since it’s traveling in reverse it should lose any information that it started with, arriving at the emitter carrying nothing but its amplitude, ΨΨ*. If I send a photon to a receiver in a distant galaxy, it will instantaneously be detected many of our (inertial reference frame) years in the future and return an ACW that I receive the instant my photon was transmitted. It reveals nothing about the distant galaxy or even whether that was where it was absorbed. If, one minute later, I send another photon that is absorbed by a passing aircraft, the ACW it returned would be indistinguishable from that returned by the distant galaxy arriving a minute earlier. This is despite the fact that the earlier photon is still years away, in our time frame, from its target – because the ACW has traveled backwards in time to reach us. This is in accord with the Relativistic Transactional Interpretation of Dr. Ruth Kastner, by which, the OW and ACW are precursors to the photon, which is then able to carry momentum and energy one way from emitter to absorber. In earlier formulations of TI, this was not clear.

Dr. Ruth Kastner developed TI into a Possibilist (PTI) and then a Relativistic Transactional Interpretation (RTI), based on the standard mathematical construct called a unitarity, and also a non-unitarity process. This allows physics a temporal direction and irreversibility, simultaneously generating the second law of thermodynamics. Simplified, the Unitarity states when particles interact, the probability of possible outcomes must sum to 100%. Increasingly, physicists disbelieve this is compatible with the asymmetry expected between the past and future of an expanding Universe (Wood 2022).   PTI explains the Quantum/ Classical boundary as the point where successful ACWs are virtually assured, preventing the propagation of quantum superpositions to the macroscopic level (Kastner 2012). Schrodinger’s cat cannot, therefore, exist in a superposition because it’s overwhelmingly likely that ACWs would be returned before it could be described in that way. It also implies that classical causality “is not  an ontological feature of the world” (Kastner 2013, 166), but the result of overwhelming probabilities of certain transactions. In my opinion, this is a sense that it seems to share with entropy.

I’ll briefly summarize RTI, while recommending Dr. Kastner’s online sites and videos. She proposed that spacetime emerges from a “Quantum Substratum” (QS) not included in General Relativity. Spacetime is constituted solely of discretely discontinuous “links” established by transacted OW-ACW events (photons) (Kastner 2021). Each emitter and absorber is outside spacetime but in the QS. The QS, she wrote, is the source of the emerging, growing spacetime structure, much like mineral-laden water is the source of crystals in a geode. Only the electromagnetic field, of which the photon is a carrier, transforms into spacetime objects, not the rest-mass quanta (emitters and absorbers) themselves. Quantum systems  acting in the present are not components of the spacetime manifold but are its precursors, as sources of “potentiality” (Kastner 2018). The past is populated by empirical observations, or actualized transactions, while the future is of offer waves yet to be absorbed (Kastner 2013). Kastner calls this space of unactualized transactions “prespacetime”, and it is connected to spacetime by the instant that defines the present: the absorption of the OW and return of an ACW completing a transaction. Positive energy can only be conveyed by a detected photon, not by an amplitude (OW) alone. This ensures that the energy is carried only forwards in time (Kastner 2012). She compares spacetime to a “knitted fabric” (Kastner 2013, 176) that continually falls away from “knitting needles” of our approximate present. This is unlike a “moving present” that progresses “toward the future”; instead, the generated spacetime recedes from an eternal present: the knitting needle analogy (Kastner 2021).

While not incompatible, RTI is more appropriate in defiance of Einstein’s Blocktime Universe, in which the future was laid out at the Universe’s beginning, and through which we move mysteriously without there being a meaningful present to separate future from past(Kastner 2013). If the future already exists to send an ACW, then TI is wrong, as there could be no stochastic choice of which ACW could be received by the emitter. It is a natural feature of RTI to generate an “arrow of time” from the emergence of spacetime, and time travel is impossible. Kastner considered a photon emitted long ago by a distant star instantaneously being observed by Bob on Earth and from the perspective of a relativistic rocketship (Kastner 2021). Even though the time order of spacelike-separated events is relative, no transaction can be set up without the availability of an absorber in the present (that is, Bob, who was not born at the time, in his own reference frame, of the emission). This also holds from the perspective of the rocket, though the time and distance separation is much shorter. Thus any photon transfer establishes the emission event in the past. Emitters and absorbers negotiate within the present (which we can identify with the QS) via OWs and ACWs, and it is only at the final stage of an actualized transaction that the “past event” is established, corresponding to the emission event. The emitter and absorber never become part of spacetime, remaining in the QS, in a sense, “eternally present”.

TI cannot be used to support a retrocausal claim to precognition for two reasons: (1) there are no ACWs returning from the future; any OWs pending the return of an ACW are in “prespacetime” and any transactions occur in the “eternally present”. (2) the ACW is not allowed to return any information about the absorber to the emitter.                 

After Daniel P. Sheehan’s The Science of Consciousness lecture, he took questions (Sheehan 2022). Asked why precognition wouldn’t take place all the time, Sheehan suggested that the second law probably obscures it in many cases, without explaining how that might (not invariably) happen. He added that from an evolutionary standpoint, it may not be helpful to be aware of the future all the time – one might be eaten by a lion in the present if one’s attention was focused on the future. Therefore precognition might normally be subconscious. Instead, I suggest that the Transactional Interpretation doesn’t allow it, that indeterminist theories of time don’t allow it, and the second law of thermodynamics doesn’t allow it. The second law is violated because entropy is proportional to our uncertainty of the position of things. If we can know the future position of photons, it eliminates all the possibilities of their being elsewhere. Dr. Kastner, in a personal communication, emailed “I largely agree with your conclusions”, but offered the following speculation allowing for premonition. More probable potential transactions in the QS (outside the lightcone) could be more prominent in awareness, leading to “cognition of potent possibilities” at sub-light speeds. Unlike precognition, premonition could  allow one to foresee an accident, and choose whether to reschedule plans. It preserves causality, indeterminacy and the second law, unlike precognition. It remains to be seen how to test it. Meanwhile, the explanation for the drawings in the future news experiment remains outside the boundaries of conventional or transactional quantum physics, which remains causal. The responsibility for our actions is preserved. 

Addendum: Professor Sheehan graciously responded to a draft of this article with the following comments. First, in the retrocausal model, future-past communications occur along a subject’s worldline, there is nothing to worry about outside the lightcone. But an “outside the lightcone” cognition of potent possibilities, as suggested by Kastner, would be necessary to reach one’s future self given that quantum transactions occur instantaneously. Secondly, Sheehan argues that Cramer’s experiment on time machines was limited to single particle effects, while precognition likely involves multi-particle systems in the brain, a “terra incognita”, experimentally. Finally, no one knows enough right now  about quantum mechanics, particularly its application to multi-particle systems, to fully explain or discount retrocausation and precognition.: he and Cyrus are offering a starting point for discussion. I believe that the future news experiments show, at most, premonition and not precognition. To show precognition, the subject would have to foresee a headline “Precognition experiment subject injured in train wreck” and get on the train and be injured any way, a high bar to clear, experimentally. Therefore, I believe my article accomplishes its goal of preserving causality, indeterminacy, free will and the second law of thermodynamics. 


Boyle, Alan. 2020. Professor tackles one more  mystery about quantum mechanics and time’s flow. Available at GeekWire. July 1

Cramer, John G. 1986. The transactional interpretation of quantum mechanics. Reviews of Modern Physics. 58(3): 1-27  July

Cramer, John G., Nick Herbert. 2014. An Inquiry into the Possibility of Nonlocal Quantum Communication. Available at: arXiv:1409.5098

Cramer, John G. 2016. The Quantum Handshake, Entanglement, Nonlocality and Transactions.  Springer

Cramer, John G. 2017. The Quantum Handshake Explored. faculty.washington.edu. Journal of the British Interplanetary Society. 70: 372-384

Graff, Dale E., Patricia S. Cyrus. 2017. Perceiving the future news: Evidence for retrocausation. AIP Conference Proceedings 1841, 030001 (2017) doi: 10. 1063/1.4982772  Corpus ID 57394439  Available at: semanticscholar.org May 31

Kastner, R.E. 2012. The Possibilist Transactional Interpretation of Relativity”. June 22 Available at www.springerlink.com/content/6t61058t2m268855/?MUD=MP 

Kastner, R.E. 2013. The Transactional Interpretation of Quantum Mechanics. Cambridge University Press. 2013. Reviewed by Chris Fields, BIBLID[0873-626X(2013) 37; pp 361-367] Available at disputatio.com 

Kastner, R.E. 2017. On Quantum Non-Unitarity as a Basis for the Second Law of Thermodynamics.  Entropy 19(3): arXiv: 1612.08734

Kastner, R.E., S. Kauffman, M. Epperson. 2018. Taking Heisenberg’s Potentia Seriously. International Journal of Quantum Foundations 4(2): 158-172

Kastner, R.E. 2021. The Relativistic Transactional Interpretation and Spacetime Emergence. March 20. Available at: arXiv: 2103.11245 (gr-qc)

Marshall, I.N. 1989 Consciousness and Bose-Einstein Condensates. New Ideas in Psychology. 7(1): 73-83

Muller, Richard. 2016. The Physics of Now. W.W. Norton 

Sheehan, Daniel P. 2022. The Broken Arrow. Time Asymmetry and Retrocausation. Available at: TSC2022 – Plenary 7 – Time and Consciousness. May 19 

See also Daniel P. Sheehan. 2020. It’s About Time. Society for Scientific Exploration, Available at: http://www.YouTube.com Mar 4

Wikipedia. 2023. John G Cramer. Available at: en.m.Wikipedia.org. Accessed March 25

Wood, Charlie. 2022. Physicists Rewrite a Quantum Rule That Clashes With Our Universe. Quanta magazine September 26

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