Why Can’t You Remember Your Future? Physicist Paul Davies on the Puzzlement of Why We Experience Time as Linear.
The curious question of how and whether we can tell the difference between an experience and the memory of an experience.
Davies writes:
When I was a child, I often used to lie awake at night, in fearful anticipation of some unpleasant event the following day, such as a visit to the dentist, and wish I could press some sort of button that would have the effect of instantly transporting me twenty-four hours into the future. The following night, I would wonder whether that magic button was in fact real, and that the trick had indeed worked. After all, it was twenty-four hours later, and though I could remember the visit to the dentist, it was, at the that time, only a memory of an experience, not an experience.
Davies writes:
When I was a child, I often used to lie awake at night, in fearful anticipation of some unpleasant event the following day, such as a visit to the dentist, and wish I could press some sort of button that would have the effect of instantly transporting me twenty-four hours into the future. The following night, I would wonder whether that magic button was in fact real, and that the trick had indeed worked. After all, it was twenty-four hours later, and though I could remember the visit to the dentist, it was, at the that time, only a memory of an experience, not an experience.
Another button would also send me backwards in time, of course. This button would restore my brain state and memory to what they were at that earlier date. One press, and I could be back at my early childhood, experiencing once again, for the first time, my fourth birthday…
With these buttons, gone would be the orderly procession of events that apparently constitutes my life. I could simply jump hither and thither at random, back and forth in time, rapidly moving on from any unpleasant episodes, frequently repeating the good times, always avoiding death, of course , and continuing ad infinitum. I would have no subjective impression of randomness, because at each stage the state of my brain would encode a consistent sequence of events.
The more interesting question deals not with the pure psychology of the experience but with how the accepted physics of time, seeded by Einstein’s relativity theory, gives shape to that psychological experience. He returns to the larger questions arising from his childhood thought experiments:
With these buttons, gone would be the orderly procession of events that apparently constitutes my life. I could simply jump hither and thither at random, back and forth in time, rapidly moving on from any unpleasant episodes, frequently repeating the good times, always avoiding death, of course , and continuing ad infinitum. I would have no subjective impression of randomness, because at each stage the state of my brain would encode a consistent sequence of events.
[…]
The striking thing about [such] “thought experiments” is, how would my life seem any different if this button-pushing business really was going on? What does it even mean to say that I am experiencing my life in a jumpy, random sort of manner? Each instant of my experience is the experience, whatever its temporal relation to other experiences. So long as the memories are consistent, what meaning can be attached to the claim that my life happens in a jumbled sequence?
In the remainder of the thoroughly satisfying About Time, Davies goes on to probe the answer to this question by examining how the history of human thought, from St. Augustine to Einstein, has left us with a model of time that simply doesn’t reflect the nature of experience, and what we can expect from the evolution of science as we reach for more complete models of this timelessly puzzling dimension of reality.
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