OK, I'm a major Science Fiction addict. In fact, most of my dreams have a science fiction bent (not kidding).

Something got me thinking about time travel again. I've developed my own theory for how this could work and avoid the paradoxes generally conjured up by such things. Note that IANAQP (I Am Not A Quantum Physicist).

When you step into that strange machine you found in the basement of your nutty deceased mad-scientist inventor uncle's basement and hit the button labelled "Do Not Press This Button under Any Circumstances", one of two things can happen. Either the machine works, or it doesn't (either we can say that no machine will ever be 100% reliable, or that the uncertainty is built into the mechanics of time travel itself). In fact BOTH these possibilities occur. In one, the normal timeline continues unchanged, while in the other you find yourself translated back in time where you end up bonking your grandmother.

In effect, the universe has forked a new version of itself at the point of your ARRIVAL in the past. You can NEVER travel back to 'your' future. Either future events will unfold much as they did in your original timeline (e.g. if you seal yourself in a box and avoid any interactions), or they don't (you decide to make changes for the good of mankind, by becoming a billionaire betting on horse races).

One interesting result of this is what occurs when you get back to the point in time you originally left from. If things have not been changed too much, your future self might still end up in that basement debating weather to hit the big red button. Once again, it might work, in which case your future self disappears in a flash of very expensive special effects (and ends up creating another fork at their arrival point), or it doesn't, in which case there are now TWO of you (one older and very rich, the other thinking that Uncle Harry really was a nutter and never invented anything that worked, except for the neutron pulse oven he was pushed into by his "faulty" butler-bot).

A downside to all this is the futility of trying to save your girl-friend from getting hit by a bus last Tuesday. You might be lucky, and travel back in time and shoot the bus driver before they start their shift (resulting in you spending 30 years in jail for murder, during which time your girlfriend marries the bloke who used to bully you in school, and you become intimately aquatinted with a bloke named Bubba and end up in a civil union together, picking out curtains for your shared jail cell). Or you may not (girl dies, bus driver lives, you end up with a house full of cats and a drinking problem). In any case, you effectively only save her for YOU - in your original timeline she dies regardless.

Anyway, just some thoughts I had. I think my Mad Scientist gene must be reasserting itself....