Post 3: The Prism of Consistency

Time travel is not a hard concept to sell. Physicists at the very least accept a form of time travel mediated by regions of space-time called closed time-like curves that allow particles to return to their starting point in time. Laypeople, owing to lack of scientific learnedness, cannot outright deny the possibility of time travel; instead they simply acknowledge its possibility without giving scientifically articulated reasons for or against its existence. Indeed, the concept of time travel is readily acceptable, but the real trouble occurs when attempts are made to incorporate it into or make it consistent with our current worldview, scientific or lay.

Scientists have a tough time incorporating time travel with current models of how space-time operates since it engenders paradoxes from which have sprung multiple attempts at rationalization. For example, if you travel back in time and murder your grandfather, how could you have even existed in the first place? One explanation (not a theory, since a theory has to be empirically falsifiable under certain conditions) is that each journey into the past opens up a new universe, complete with an alternate history that leaves the original world untouched. Another explanation, a complete cop-out, is the Hawking Chronology Protection Conjecture (not a theory…again) which states that any configuration of time or matter resembling that of a time machine is impossible. Scientists, who are supposed to be voices of assurance in a sea of uncertainty that is modern physics, squabble over interpretations of time travel. The apparent trend is that each physicist comes up with a different conjecture to fit the way in which he or she perceives the world. Such a practice, while able to incorporate time travel with various models of space-time, comes with the clear disadvantage of theoretical disunity.

Laypeople find time travel difficult to conceptualize since their minds are trapped within what philosophers call a prism of consistency. That is, humans are generally unable to think outside an imaginary box in which time is systematically considered to flow from past to future. After all, we consider a past to future time scheme to be axiomatic, driving our everyday life and giving meaning to time-keeping devices and even causality itself. No turn of events, no law of physics in our daily existence seems to suggest that time can flow from the future to the past. By contrast, when we are immersed in the world of science fiction, we take the reversal of the ‘arrow of time’ in stride. And as soon as we set down the novel or turn of the TV, our minds again settle firmly within that prism of consistency.

Still, if we liken the gradual acceptance of time travel to a dramatic paradigm shift in the history of physical science, we may be in luck. Consider a historical example, the advent of the heliocentric worldview in the 1500s. Laypeople back then had no reason to believe that the Earth moved around the Sun; after all in their daily experiences, it was the Earth that stood still, not the Sun. To them, the Sun’s revolution around the Earth was as axiomatic as two plus two, yet nowadays the mere thought would be considered ignorant and even laughable. What if modern-day doubters of time travel turn out to be just like those folks who back then doubted heliocentrism and were unable to escape their own prisms of consistency? If history is to provide us an example, it would be that what is considered radical in one age may be one day considered fact or even axiom. Perhaps the first big step towards making time travel a reality is to actually believe that it is possible. As for the exact mechanism that would enable time travel to occur? That’s a whole different story.

—Sean Justin Lee