So I have a bit of a problem with recent representations of time travel I’ve seen in some TV shows.

On The 4400, people from the future abducted people from different times in the past and then returned them all to August 14, 2004. I would think that the future people could have been less obtrusive by returning the 4400 to the same time as they’d left.

On Doctor Who, and maybe there’s a well-documented reason, once he finds a weird thing in another time, why doesn’t he travel to a time and place to warn himself or somebody else, or just stop the weird thing from even starting in the first place?

I mean, I’ve seen Back to the Future (parts 1, 2 and 3) and Bill and Ted’s Excellent Adventure (I saw Bogus Journey, but I refuse to comment) and I know that by travelling in time a person can appear in the same place more than once, and can ensure that stuff appears in the past if they remember to go back and do it later. And if Star Trek has taught me anything (and let me assure you it has), I can alter history (past and future) however I like, but eventually at some time in the future there’ll be Time Agents to fix everything.

Can we not have one simplified theory of time travel?