SPOILER WARNING: This post will contain spoilers for Legends of Tomorrow, and possibly for the Arrowverse in general.
So, I just got done watching the finale of "DC's Legends of Tomorrow." Overall, for a DC novice like myself, it was a fun experience watching characters I'd sort-of-heard of galavant through time. Lest anyone label me a Negative Nancy, a breed the Internet has a surplus of, I'll single out Wentworth Miller, the always awesome Victor Garber, and Brandon Routh for their fine work in the show, and we all know Arthur Darvil is getting a kick out of not-quite playing The Doctor. (Time (aha) will tell if killing Miller's character off is the disaster for the show that it feels like to me)
Anyway, the thing that strikes me about LoT is that it takes the most spectacularly bone-headed approach to time travel I have ever seen on TV. The only thing that comes close in terms of sheer WTF factor is the movie "Looper", a film of such monumental stupidity that I suspect that when the screenwriter dies, the total IQ of the planet will increase. In the finale, the team finally has the opportunity to kill immortal bad-lad Vandal Savage (a guy who probably went to the same Evil Name Class as Damien Darhk and Killgrave) by killing him at three places in time, simultaneously, because due to the shenanigans he's pulling to reset time back to ancient Egypt, he's briefly not immortal any more. If your monitor, phone, or tablet just turned itself off, it's simply reacting to how outstandingly dumb that previous sentence was.
Leaving aside causality for a moment (keep the faith, causality fans, we'll get there) let's look at one of the more common bits of boneheadedness the show uses. I call it 'Narrative Time', and TVtropes seems to call it San Dimas Time. The idea that three events, in three completely different time periods, are happening 'simultaneously' makes exactly no sense unless the time frame from which the viewer is watching is the only one that's real. On multiple occasions in the show, the characters will be onboard the TARD Wave Rider acting as if they only have a short while to prevent something happening, even though that something is happening in the year 1978 and they're currently travelling back there from 2016. Of course, you need to preserve some narrative tension, but the knots the show ties itself in to get there are incredible.
Now, on to causality (told you we'd get there). So, the whole point of Rip Hunter's mission in the first place was to stop Savage killing his family in the future. Why not just pick them up in your fancy time-ship and move them, we ask? Apparently every time he's tried. he fails. We don't get any more detail than that, which is lucky because it's the dumbest thing since they built a firework factory on a Zeppelin. Anyway, they fail to prevent the death of the wife and child (despite still being able to go anywhere in time to try again) but decide to stop Savage anyway. (Despite his triumph coming over a century after they'll all be dead of old age.) Of course it's lucky they ignore my snarky brackets, because Vandal is in fact about to blow up all of time post ancient Egypt. Oh hell, now my own post is going back in time. Anyway, much heroics, characters previously unable to so much as ruffle big V's beard beat him like a government mule in three time periods at once, and victory! Thing is, that means our Big Bad just died in 1958, and since he went back in time and told his younger selves what to do as part of his Evil Plan, that means there's still only one of him, even if for a while in each timezone there were two of him. So, with him dead in '58, he can't be alive in the other two timezones (and he'll miss Woodstock). So Rip's family is saved, yay! Or nay, because apparently they aren't, and killing El Savago in '58 doesn't do a damn thing to him in '75 or 20-whatever. By the time another TARD Wave Rider has shown up with a message telling them not to get on their own ship again or they'll all die, Time might as well pack up and move to a Refuge For Battered Metaphysical Concepts, because she's been well-and-truly done over.
Let's not worry ourselves about the fact that at the end of this season of The Flash, Barry seemingly deleted his own show by time-travelling back to his own origin story and stopping it. I still don't know how Eobard had GIDEON, or where she went after his defeat.
DC have a bad rep for messing up their continuity so badly that they occasionally have to blow up the world and start again. It's a bit of a shame that this is creeping barrelling headlong into their TV output as well. With Supergirl apparently coming into the fold too, heck knows what's going to happen next. Or has happened next. Or happened last but didn't not happen yet.
I think if Rip Hunter suddenly turns up in "Gotham" I might do something dramatic.