It cant prove or disprove time travel.
Whether there are multiple time-lines or not, to state that science can't prove or disprove time travel is too broad of a proclaimation. To be able to prove or disprove any number of individual time travel claims is entirely different. With regards to the claims of being a time traveler, I stand with Rainman and Darby on that issue, and agree with them that those CAN BE either proven or disproven through science.
IF someone makes the claim of coming from the future, then in such a case, it IS up to the claimant to prove their claim. IF they describe their machine, and it is physically impossible, as per the Laws of Physics, Aerodynamics, etc, etc ; THEN there is a problem of fact verses fiction.
IF they provide a list of "predictions"...and those don't come to pass, or as Rainman said, start trying to proclaim success as they attempt to "fit square peg's in a round hole"; then throw down some sort of time-line variance percentage factorization as a reason why their predictions didnt come to pass...then some of us apply our own variance percentage factorization to the claim...and the scale starts with a Zero and runs to None.
Relative to ghosts, as I said, with some instances, I simply don't know. But this isn't so with every single instance, there are hundreds, if not thousands of supposed ghost stories that science has been able to de-bunk.
There is a reason as to why there is a Time Travel Claims section...whether the odds are any time traveler actually bothers to reveal themselves, isn't really relative to the creation of that Forum.
There is also a reason as to why there is a Paranormal Forum, as well. To the thinking person, there is a definitive difference between someone physically using a construct to traverse time and space verses someone sitting at a table with Tarot cards and claiming to be able to "see" into the future.
When I said that Science doesn't have ALL the answers to ALL of the experiences ; in no way is meant to detract from the value of science/engineering nor alleviate the necessity for educated and experienced scientists/engineers that maintain a rational perspective, and not be swayed by emotional responses.
As it is, I am with Rainman, Darby and a few others...that no "real" time travelers has come to TTI ( or have revealed themselves to date ), and the claims thus far
have been "scientifically" disproven. That a time traveler might or might not arrive at some point in the future, to that possibility, I simply don't know.
The probabilities of one showing up and posting here at TTI, are against such an occurance, but one can always hope. Until then, every and all claimants of time travel should know that they will be expected to pony up some proof that can be validated, or be relagated to the science fiction category.