here's a question on time, by zeno on his Progressive Dichotomy Paradox that 1 will never reach his destinatio
465495
Zeno ignored the fact that the infinitely many smaller steps take infinitely less amounts of time to do.\n\nAs the earlier answerer pointed out, sum the power series and you get a finite value for the time taken...\n\nLike a lot of these logical tricks, there's something being forgotten or ignored to make it look impossible.
601936
I believe that true time is simply another dimension we just haven't figured out how to move in any but one direction. Time as in seconds, minutes, etc are nothing but a random measurement we have placed on that axis; more random than how we chose inches, feet, or meters for the other axis'.
31234
Einstein said we are living in the past time, that means we have not "now time"!\nSo, nobody can not answer, what time is it! maybe we can ask, what time was it!!
943807
The product of space and time is not so much an abstraction as much as an aberrated perception. ( Why, In GR theory, is everyone always going deductively DOWNWARDS into the collapse rather than inductively tracking the event back to original precipitating events?  The answers are THERE.)
920732
No because, while time may pass at different rates for different people, they are all still "in the present."  You don't have one person in the past and one in the future.
20367
Well, its pretty much as crimsonmoonvc said.\n\nUnlike the spatial dimensions of perception, time is not directly accessable by any sensory organ. We precieve time by the unfolding of the events around us.
594980
No, to address Zeno's Paradox, the infinite number of "baby steps" you must take is offset by the infinitesimal amount of time it takes to make each of them.  More precisely, even though when you run a race, you can't cross the halfway point until you get to the quarter point, which can't be crossed until you get to the eighth point, ad infinitum, if s(t) represents the possible distance that can be traversed after the first t seconds, then as s(t) -> 0, t -> 0 as well.\n\nBefore the advent of calculus, we didn't have a well-known mathematically precise way to deal with the idea of infinite sums.  Now, we simply can work with the definition that infinite sums are limits of the sequence of partial finite sums.  Therefore to say that we need to cross the halfway point, then the 3 quarters point, then the 7/8ths point, ad infinitum to complete a race, we can express the completion of the race by noting SUM_{i=1}^n 1/2^n -> 1 as n -> infinity.
110555
What a great philosophical question!\n\nIndeed, none of us can escape from time.  It’s everywhere and unstoppable.  \n\nBut that doesn’t make us prisoners, I don’t think.  \n\nTime is an artificial construct that was invented by humans to keep track of… well, time.  When we were just Neanderthals, I don’t think our ancestors worried about time too much.  It simply was just not important to them.  Later on, people started counting days, and artificially decided to make it 24 hours per day, 60 minutes per hour, etc.\n\nGiven it’s only an artificial construct, I don’t think it’s capable of making anyone prisoners.  The only difference is what we do with the time in our lives.  As to whether “time” still exists after death, that’s another topic of discussion for another day.
1105069
a paradox is an apparent contradiction, but not nescessarily a contradiction. something thats counterintuitive
745402
Time is like light it curves, and we are part of a time line that can not be changed if it was to do so we would be living in a parallel universe so yes time dose exist.  Oh by the way here is a little test to prove that time dose exist it just dose not matter.  The next time you see some one look at there watch count to 30 and ask them what time it is, the person will then look at there watch again and give you the time.  The point is only 30 sec has gone by yet they had no idea what time it was this is because people do not care what time it is , they care about what time it is not.  they know that there meeting is at 3pm it's only 1pm  there fore they can care less what time it is.  So with that said time exist, but really dose not matter.
18909
Time is just a concept, it does not really exist. We track time by the movement of celestial objects in the universe and light but time is abstract.
971853
Time is what prevents everything from happening at once.  ~John Archibald Wheeler\n\nhttp://www.quotegarden.com/time.html
736224
The fact that he took his return trip later just complicates the problem. The question can be restated as one person leaves from the top of the mountain and one person leaves from the bottom of the mountain. They leave at the same time. Explain why, if they follow the same path, they will run into each other each other at some point. Stated this way, it is obvious, right?\n\nIf you want a more rigorous solution, here you go. This is a continuity question. Let f(t) denote the distance *from the bottom of the mountain* at time t on the trip up the mountain and let g(t) denote the distance *from the bottom of the mountain* at time t. Change your units so that your time starts at zero (so 8AM is t=0) and you make it up the mountain in time 1 (so 1PM is t=1) and your distance from the bottom to the top of the mountain is 1. With this set up, g(x) lies in the interval [0,1] for every x in the interval [0,1], and the same holds for f(x). Consider the function g(t)-f(t). The physical interpretation makes it clear that f(t) and g(t), hence g(t)-f(t), are continuous functions of t; that is, you don't just disappear at one point and reappear at another point without having travelled through every point in between. g(0)-f(0)=1-0=1>0 and g(1)-f(1)=g(1)-1<=0. The intermediate value theorem tells you that there is some time t_0 such that g(t_0)-f(t_0)=0. That is, there is some time t_0 such that g(t_0)) = f(t_0). Your deja vu moment happens at time t_0.
929095
Yes it is consistent with Special Relativity. K is not advocating time travel or travelling faster than the speed of light, nor any other Relativity flaunting theory. He is merely stating you can not live in the past, nor understand life by predicting the future.
676857
Assuming time travel is possible, I think such a senario might be possible.  The trouble people have with time paradox lies in the assumption that every thing in the universe shares the same time line.  Why should that be true?  Here's an example:\n\n\n------  X  -------------------  Y  ---------\n\nAbove is our theoretical timeline.  Y represents me, in the "present".  I use my time machine to go back to X, before my grandfather sires my father, and kill him.  Logic dictates that I shouldn't exist.  What I'm suggesting looks like this, instead:\n\n---------------------------  Y  ------------\n                             \n\n---------------------------  X  ------------\n\nX & Y still represent me & my grandfather, but each of us now possess our own separate time line.  Instead of "going back in time", I simply hop off my timeline & onto his.  I am now free to perform my assassination, without consequence to me (beyond the obvious legal ones), as I was not born on this timeline, but my own.  Whether or not I can now return to my own timeline is an entirely different question, however.
713458
I think your question is a good one - and not at all "dumb as why is the sky blue."\n\n"Now" is a point in time between the past and the future. \n\nIt may well be infinitely small (no dimension - like a "point" on a "line" in mathematics) or it may well be a quanta of time - perhaps time isn't the smooth continuum we tend to think it is, but rather exists in small packets or quanta.\n\nI'd rather suspect, that given the relative nature of different rates of time, it is most probably a smooth continuum. \n\nI also believe that "now" is simply a term with no real scientific meaning, but rather just a reference to the term "immediately" - as in, "Do it now."\n\nInterestingly enough, I have never thought about this in the past, but "now" is about the time I should retire and perhaps think more about it in the future.
114656
It's not necessarily impossible according to theory, but given our current technology, it's out of the question.  There's a lot of trouble with time travel theory, including multiple paradoxes.\n\nThe most famous paradox is, of course, the grandfather paradox.  It goes something like this: One day, after you've built your time machine, you decide to travel back into the past to shoot your grandfather before your father is born.  Here is the major paradox, if you suceed in killing your grandfather, you couldn't be born to go back and shoot him.  Just as well, the conditions required for you to shoot him couldn't exist and thus he lives.\n\nStill on the 'travel back in time to shoot grandpa' string, several other things could happen as well.  You could be transported to an alternate timeline, similar to ours, but not ours, and whatever you do there doesn't affect anything in our time line.  You could go back and try and kill your grandfather, but you are thwarted in every attempt, which tends to imply some sort of destiny or grand scheme.  You could try to go back in time but are ripped to shreds because every fragment of your being wants to be in its natural time.  There's a million and one other things that could happen.\n\nThat, I believe, is not necessarily answering your question, though.  Time itself is not understood by physicists even now.  What it is, no one is quite sure!  (However, I'm fairly certain time is related somehow to mass.)  One thing that's always for certain is time moves forward in a very linear fashion, cause followed by effect otherwise called casaulity.  I can't say one way or another why exactly we can't go back in time and I won't say it's not possible, some theories say it is.\n\nHowever, I believe Stephen Hawking offered up the best proof against time travel to date: Wouldn't there be time tourists from the future visiting us if time travel was feasible?