(this was written for the question on time travel, but might generate some discussion here, too)



I believe that the answer to your question is: definitely not.  The argument is as follows:

Thinking about time is complicated by the role the concept of "time" as our fourth dimension has come to take in our daily lives.  We experience it almost as a physical presence, imposing itself on us at all hours of the day and night, determining large parts of our lives: our working day, the timing of our meals, our appointments, holidays, the availability of essential services and products, our access to  civic responsibilities and rights.  It takes on an additional degree of reality as a major component of our consciousness: the memory of our past, imposing itself on our perceptions at every moment, always ready to be visited in thought.

Getting a handle on your question becomes easier if we think, as have some philosophers as early as pre-socratic Greece, of the fourth dimension not as time, but as the universal, everlasting process of change in which we find ourselves; a process partaken by everything from the smallest atomic particle to the cosmos itself.  And of "time" as a convention developed by humankind over millenia to describe and measure the regularities observed in this process: day and night, the recurring seasons of the year, the motions of moon and planets.*   Similarly, we do not perceive the world stretching out in front of us in terms of feet or meters; these do not exist in themselves, but are among the units we've agreed to use when measuring the other three dimensions.

We perceive this underlying cosmic process of change as unidirectional, moving inexorably from a remembered past and present into an unknown future - the famous Arrow of Time, which appears to "obey" the second law of thermodynamics. A reversal of this process would not at all be like running a moving picture film backwards: all the infinite subatomic particles which make up our world would need to remember and turn back precisely on their paths, those which have decayed or otherwise disappeared reappear at the proper moment, even those particles as yet unknown to us...  and the principles of symmetry would seem to require that any such reversal be mirrored throughout the universe.  The mind boggles, and even science fiction writers gloss over this problem when imagining time travel.

Some physicists have based hypotheses of "going backward in time" on the claim that equations describing processes in time continue to be mathematically valid when reversed.  But none of the descriptions which I have seen appears to take into account the fact that whereas the original equation of a process occurring in time has an unknown, open-ended forward movement, its reversal, to correspond to underlying reality, must factor in the memory of a known past, is therefore not identical.  In Hobbes' famous metaphor, this is mistaking symbols detached from reality for real money.

The idea of travel in time runs up against similar problems.  Quite apart from the problem of transportation, time travel by humans to a specific moment x in the past (I assume you are thinking of time travel on Earth) implies the existence of that moment under one of two hypotheses, both problematic: either that it can be reconstituted, the exact subatomic structure of the world recreated as it was at the desired target moment. Or that, like our memories, the past itself, in all its extension, is still somehow "there" to be visited - surely temporarily, with the possibility of returning to our ever-moving present afterwards.

Neither of these hypotheses could take place in our own fourth dimension, since the past obviously cannot physically coexist with the present.  Nor does the re-creation hypothesis fit well with the fact that a large part of the particles existing at any moment in the past have decayed or otherwise disappeared in the meantime; or that our current knowledge of quantum mechanics does not allow us to determine both mass and position of even a single particle, let alone world or cosmos!

So can we imagine all past moments as continuing to exist in some limbo outside of our fourth dimension, perhaps in an infinity of other dimensions, unchanging (otherwise they would not continue to be our past) but ready to resume change (but in what direction?) when a visitor from the future arrives.   This thought can perhaps be put into mathematical symbols, and even manipulated in that language.  But when set down in ordinary language and related to a stubbornly independent underlying reality, it takes on the character of a very human wish-fantasy, perhaps responding to nostalgia for lost childhood, for a simpler, purer past, or for escape from the present.  Again: the underlying process of change is unidirectional; the past does not exist any more to be visited, except in the traces it has left in the world around us and in our individual memories.




* Our measurements of time are based on newtonian physics.  Thinking of the fourth dimension in terms of change, rather than time, can also make it easier to wrap our minds around some of the ideas in relativity theory: e.g. that particles of matter or light, under extreme conditions, may behave and measure differently from what newtonian physics would lead us to expect.