Reading: Deutsch, David and Michael Lockwood. "The Quantum Physics of Time Travel" in Science Fiction and Philosophy: From Time Travel to Superintelligence, Second Edition. Edited by Susan Schneider. John Wiley & Sons, Inc. 2016. Pages 370-383.

 

In the fifth meeting, the above reading was presented by Inbar Noy.

 

Deutsch and Lockwood present the idea of Closed Timelike Curve (CTC). They present a theory of using both Time and Space to Time Travel. This is allowed in the time-loop created by the CTC. If a person traveled using the CTC – they would meet all the people that used this particular CTC – it is a meeting point. In the article, they present different and competing explanations from the literature regarding Time Travel, delving into the issues of possibilities and probabilities – all events are possible, and should have their probability properly assessed. The CTC allows the Time Travel because it is like a "closed system" which preserves its own equilibrium, in which the people who travel can be seen as "packets of information" that move through it. An important point is that the CTC reaches back in time (to the past), only until the moment it was initially created. Meaning, the moment the CTC would be created, the probability of the possibility to Time Travel is no longer zero.

To illustrate the movement of time, Inbar presented an experiment that illustrates how time can move differently in relation to space.

 

One member said that one way to time travel is visiting an "Open Museum" – a type of museum that has a periodical setting, with actors acting as people from that time period in periodical clothing. This is a manner to explore a travel through history, both for the visitor and the actor who reenacts the role. It was likened by someone to a Zoo (and one could say a "Historical Zoo").

Going back to time travel, and drawing on the reading and the experiment, we discussed if we can time travel to the future. Rather then the Grandfather Paradox – what about a person who wants to travel to the future to see their great-grandchildren? We agreed that our (personal) time is relative to us. We brought up a known hypothetical experiment – of an Astronaut with a Twin. The Astronaut leaves Earth on a spaceship, traveling at the speed of light; the Twin remains on Earth. When the Astronaut returns to Earth, time would have traveled differently for the both of them – the Astronaut would be younger.

We discussed the Knowledge Paradox – exemplified by an Art Critic and an Artist. The Artist travels to the future and sees a review of their art piece (say a painting) by an Art Critic – including the piece itself. The Artist travels back to their original time and creates the art piece. Where did the art piece originate from? Is the painting that was created actually a copy? Are there the same nuances in both of the paintings?

The discussion then moved to the Psychological implications time travel can have on the human psyche. Humans are social creatures, that ground themselves with human connections; we wondered about the human element – the time-traveler themselves, and how they would be affected from moving through time. Would their sanity be affected? Given the rapid change of the last decades, how would a time-traveler adjust to a new world? Or, alternatively, would they be able to adapt to circumstances that are different, and unhook themselves from the tight connectivity of our day and age? What about "Fear of Missing Out" (FOMO) – if a time traveler travels to the future, how would that impact them? Then, suppose you can only observe events, but not influence them – wouldn't that affect you?

From the popular culture, we brought up Captain America – and how he reacted to reality having changed as he was woken-up 70 years into the future; and Dr. Who, who never ages, but has human companions that he would always outlive and outlast.

We also discussed how the human element would be affected physically – space makes you taller; but would there be other effects? What about your cycadean rhythms? Your biological clock?

From the Social aspect, one of the members claimed history is romanticized and that there is a "sterilization of the past" – some issues are not discussed, such as hygiene and its different forms.

The meeting had us wondering about how a time-traveler would do in relation to themselves and to their new surroundings – when making the trip there and back again.