Time travel??? Is it possible?
To the extent that a brain compares information about its environment and the state of its personal thoughts/feelings with another similar set of [stored] information, and detects a change between the two -- designating one as "current" and the other as "past"... Then the contrast of one different cognitive evaluation like that to another "seems" to already be the case. I.e., the average person may construe themselves as "traveling in time", moving from moment to moment (transitioning from one sensory state of the outer world to a slightly altered configuration).
But if what you're desiring instead is to radically "jump" from one evaluated state of affairs like that to another one that is measured as being days, weeks, months, or years away from what's judged as the current one -- without having to cognitively "pass" through the intervening changes or differences between the two "widely" separated conditions, then... That's very unlikely to happen (if not impossible) as far as one's physical body making such a jump.
Psychologically, though, an individual in a deeply comatose condition could wake up in Rip van Winkle manner (prior to looking in a mirror) and discover they have subjectively leaped over a sequence of many changes "instantly", albeit the conclusion not being justified from an objective standpoint.
Similar with cases like
Henry Molaison and
Kent Cochrane. Perpetually locked into the view of a younger version of one's self repeatedly making contact with the future, but constantly forgetting that misapprehension and re-encountering it again and again.
- HM, the Man with No Memory
https://www.psychologytoday.com/us/blog/trouble-in-mind/201201/hm-the-man-no-memory
EXCERPT: We measure time by our memories, and thus for Henry, it was as if time stopped when he was 16 years old, 11 years before his surgery. Because his intelligence in other non-memory areas remained normal, he was an excellent experimental participant. He was also a very happy and friendly person and always a delight to be with and to assess. He never seemed to get tired of doing what most people would think of as tedious memory tests, because they were always new to him! When he was at MIT, between test sessions he would often sit doing crossword puzzles, and he could do the same ones again and again if the words were erased, as to him it was new each time.
With respect to speculative fiction accounts of "time-travel" in a physical "big jump" context, that's not even allowed in one of the three or four usual options we have for time conception. In
presentism, there are no past or future intervals to transit to (only a global configuration of "right now" fleetingly exists). And it's actually the commonsense view that most people on the street are supposed to be entertaining.
The others are
eternalilsm, the
growing block universe, and the rarely examined "
shrinking block universe".
So in terms of the putative if not imaginary average person's beliefs, time travel is excluded by default. Even the ordinary kind of presumed time travel -- of speciously "moving" to the next moment or different state -- is gone. Since that moment doesn't exist yet, and the one prior to Now. When the next does, it replaces the latter (annihilates it). There would be no "travel".
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