Hi
I think that the people posting here have a different interpretation of time. If this is true which it probally is on some level - we are discussing a topic which everyone is seeing in a different way to one another making any real argument unrealistic and kind of pointless anyway. Ask yourself - why am i really posting here?
The defination of time differs from person to person. A man who has a pretty good knowledge of it is Einstein

.. In a way his interpretation of time did not include a past present or future, these are all mere measurments we use to coordinate our days, essentially a clock does not tell the time, it is only a battery operated dial which moves around a face with numbers inprinted on it, used for measuring the things we need to.
Einstein understood time specifically as 'a measurement of the motion of matter'. He also understood that it is sometimes wrong to think of matter in subjective form and that it makes more sense to consider all matter as one unified whole...
So when we think about creating a machine to sit or stand inside of and travel back in 'time', in effect and affect what we are doing is 'reversing' what we perceive to be the 'present' and all its surroundings backwards in its motion - like unwinding an object which has been twisted, 'time' (the motion of matter) is not like a catalog where we can flick through and pick a date of arrival, it is a constant unfolding/change of matter, if it was possible reverse this it would cause a so called 'butterfly affect' which would disturb the entire universe, eventually.. (thats if it was done ofc)..
Here one could argue that the time machine would be indepentent of the space and matter surrounding it - allowing it to function in its own contained space not affecting that around it.. But a little thought into this shows that it would only have the ability to experience past time within that small space of which the machine occupies, making it an all round pretty boring experience as we would not be able to experience anything bigger than the machine itself or its container... So no Hitler meetings and no visiting the cave men to give them a torch or whatever.
I think more than anything people want to believe in moving through what has already been or what has yet to come. I think that there is no other time than the moment before your very senses, if you seemingly live a few steps behind, in memories, you are not there in that memory, you experience the memory as an activity within the brain in this ever changing moment, many things are happening while you maybe think you are 'somewhere else in time' ofc..
''
Time'' is a
measurement of matter.
All ''Matter'' including us as natural human beings are interconnected with all other matter in the universe - this is clearly evident as we breath in 'air' which fills most of space.
Reality as we know it is always changing due to the physical laws of nature, why would it go back on itself?