NOTE: This is a very complicated theory. I may natter on a bit. Please bear with me in that situation.
WARNING!!!
This post will contain multiple spoilers for Milo Murphy's Law. If you have not seen all the episodes so far, do so. The entirety of this post is based on spoilers.
Now that that's done with, let me proceed.
In the episode, World Without Milo, Elliot the crossing-guard--what's that? Oh yeah, sorry--the Safety Czar, gets his wish. As you can guess, he gets a glimpse into a world where Milo does not exist, and nobody even knows who Milo is. Near the end of the episode, Cavendish and Dakota show up in their time vehicle. Apparently, they accidentally changed something in the past, and now Milo doesn't exist. (And seemingly, there's also Milo-shaped balloons and talking squirrels.) Elliot asks why he's the only one that remembers Milo. Dakota in reply asks if he has a lead-lined stop sign there, and Elliot thinks it is. Well, that must have shielded Elliot's brain from the time waves, Dakota surmises. It did not, however, shield his head from that telephone pole. And the rest, you can see in the episode.
So what, you ask? So what if he's got a lead-lined stop sign? The writers probably just threw that in so it'd make SOME sense! It's not important!
I don't think so. If Murphy's Law is that anything that CAN go wrong WILL go wrong, Milo Murphy's Law is that EVERYTHING THAT COULD POSSIBLY be important WILL be important. The tiniest details could end up being vital to saving the world. And I think this whole notion of 'time shields' is much more important than we think.
I don't think so. If Murphy's Law is that anything that CAN go wrong WILL go wrong, Milo Murphy's Law is that EVERYTHING THAT COULD POSSIBLY be important WILL be important. The tiniest details could end up being vital to saving the world. And I think this whole notion of 'time shields' is much more important than we think.
For my first and probably biggest example, let me direct your attention (unless you're Cavendish) to the Island of Lost Dakotas.
So, in said episode, we find out that Cavendish dies on the job. Apparently a lot. And every time, Dakota goes back in time, switches places with his past self, and saves Cavendish before whatever happened HAPPENS. Then the past Dakota takes a postcard (given to him by the other Dakota) and goes to a remote island. That island is populated entirely by him--lots of him. Those are all the past versions of himself, sent there after Dakota saved Cavendish. They literally have their own civilization there.
But there are several things that don't make sense. First off, why doesn't Cavendish notice that there are multiple time vehicles littered all over the timeline and the world? If the multiple Dakotas don't disappear, neither should the time vehicles.
To be honest, that could make for an easy out in the Pistachion Invasion plot--Fungus Among Us and all that, I mean. Dakota could just go to anywhere in the world, and take that time vehicle back in time to prevent the whole thing from happening. BUT that's not even the worst of it. Because this whole multitude of Dakotas should not even exist.
Why is that? For the answer, we have to go back to the beginning of summer...
Well, actually, we have to see what happens when Future Candace goes back to the beginning of summer.
In the Phineas and Ferb episode, "Phineas and Ferb's Quantum Boogaloo", Phineas and Ferb go thirty years into the future. Future Candace takes their time machine back to the beginning of summer (like I said), and busts their rollercoaster caper to their mom. When she (Future Candace) returns to her own time, it's... different, to say the least. A despotism ruled over by Doofenshmirtz where children are outlawed and everyone has to wear lab coats, to say the most. Well, not the most. The most would be an encyclopedia entry, or possibly the entry on Wikia.
So, anyway, she goes back in time to stop herself from busting her (much younger) brothers. Then the both of them go to Phineas and Ferb after the crash of the rollercoaster, and explain the whole situation. (I think the time machine got busted or something, and they need to fix it.) Basically, this is what happens:
Again, sorry for the bad quality!
Since Phineas and Ferb and Milo Murphy's Law both happen in not only the same universe but the same town, I'm going to say that the laws of physics (such as they are) are the same. Two versions of a person from alternate timelines can exist simultaneously. However, they can't exist like that indefinitely. Coexist is not an option. Eventually, the one from the bad future, or the future that doesn't exist anymore... poofs. Admittedly, there is a delay. It honestly seems like it's delayed until someone points out that the one shouldn't exist, and then physics are like "Oh darn" and kick in to poof the one out of existence.
We see this same situation in A Christmas Peril, the latest episode of Milo Murphy. Future versions of Cavendish and Dakota go back in time twenty (I think) years to prevent their past selves from parting ways. And they go to some insane lengths, let me tell you. But after they succeed, all the numerous future versions disappear (or, uh, poof) leaving their past selves standing in the wreckage. That's how it worked in P&F's Quantum Boogaloo (except the wreckage part) because those future versions were from a future that did not exist. And it even happens after they realize that they shouldn't exist. So time still works the same way.
BUT... how does that work with the Island of Lost Dakotas?
When Dakota prevented Cavendish from dying, he was also preventing a future where Cavendish did not exist. But that would mean that the him that knew about it would poof out of existence. And he did not. All those times, and not one of him poofed. He somehow lasted long enough to get onto some kind of transportation and get to the island. Unless we're literally going to say that the whole poofing-out-of-existence thing WILL NOT TAKE EFFECT unless they realize that they should not exist. Which, to be honest, could work, what with the "Phineas and Ferb Logic" aka "Down With Physics". But that's a huge stretch.
This is where time shields come in. Time shields are basically a certain object, usually lead-lined, that are unaffected by time waves, and can shield a person's brain from being affected by time waves as well. That means that person wouldn't forget something that had been erased from existence, as in the case of Elliot and Milo. But if the shield was big enough, it could potentially shield the person from being erased themselves.
Hmm...
Let's take a look at this thing. The first time Cavendish died, Dakota would have had to do a LOT of planning to figure out what he needed to do. And I've gotta hand it to Dakota on this one: something like this takes careful planning and precision. It's really a compliment to his intelligence that he was able to successfully pull it off. Anyway, everything had to be perfect, or it might not work. My thinking is that he picked that specific island for a reason: there was a naturally-occurring time shield around it. Because of that time shield, the alternate hims wouldn't be affected by the time waves, and thus could continue existing there on the island. However, it's more complicated than even that.
(You probably just groaned and said 'of COURSE it is...' didn't you?)
First off, why wouldn't he just let the alternate hims disappear? It would be a whole lot less trouble for the present him. Plus, Cavendish wouldn't be able to accidentally find the alternate Dakotas, as he might with an island. So why not? Did he just not realize that they could poof out of existence?
Of course he realized that. He had to be really precise, as I said before. He would know that they could just poof. So I think he had a reason for keeping all these alternate hims on that island. I don't know what it is. But I suspect there's some sort of purpose--there always is. He wouldn't decide on all that if he didn't have a reason.
But the second objection to this theory is stronger: it still doesn't take care of the fact that all the 'Lost Dakotas' shouldn't exist. Well, that's because I haven't explained that part yet. And now we get into the really complicated stuff.
Let me first specify that I'm not going to attempt bending the laws of physics like Phineas and Ferb. This won't mess up anything that's already established in the shows. If it did, it wouldn't be a good theory. Just to get that out the way.
So, Dakota goes back in time just a few minutes, and prevents Cavendish from dying. The one that went back in time is the one from the Bad Future, and so would be the one to disappear. But anyway, like I said before, there seems to be a short delay on the whole poofing thing. Because he only went back a few minutes, the delay lasts long enough for him to progress naturally past the time at which he went back. That way, he himself won't disappear.
But there still can't be two of him from different timelines in the same one. That's a big no-no, as he said himself. So, the timeline would compensate by erasing the other one, aka the past version that Dakota switched with. And yes, this would also mean that the many, many time vehicles littered all over space and time would disappear as well. So now there's just the one.
Okay, that makes sense so far. I think. But how does the Island of Lost Dakotas still work? Well, when Dakota goes back in time, he gives his past self a city bus pass and a picture or postcard of the island. My thinking on the matter is that the picture acts as a Time Shield (maybe it has some lead in it or something). Present Dakota gives it to Past Dakota, which keeps the latter from nonexistence as he proceeds on his way to the island. When he gets there, he's safe, because of the naturally-occurring Time Shield around the island. Which I mentioned earlier.
But then the Present Dakota also told his past self to "send me a postcard". The postcard is the picture. This way, he gets the picture/Time Shield back so he can give it to his past self the next time this kind of thing happens.
Oh, wait, there's another point I almost forgot. Why does he give himself the picture? Wouldn't he already have it, since he's, you know, the same person but from five minutes ago? Then again, that's really more a flaw in the story itself than with my theory. But I'll see about it--maybe there can only be one of any certain Time Shield in a timeline. When Dakota tried his plan the first couple of times, he found out that once he went back and crossed his own timeline, the Time Shield/picture his past self had disappeared. Maybe. So he has to give the Time Shield to his past self, or it wouldn't work.
Oh, wait, there's another point I almost forgot. Why does he give himself the picture? Wouldn't he already have it, since he's, you know, the same person but from five minutes ago? Then again, that's really more a flaw in the story itself than with my theory. But I'll see about it--maybe there can only be one of any certain Time Shield in a timeline. When Dakota tried his plan the first couple of times, he found out that once he went back and crossed his own timeline, the Time Shield/picture his past self had disappeared. Maybe. So he has to give the Time Shield to his past self, or it wouldn't work.
One more thing hasn't been explained: why the older Dakotas all poofed in A Christmas Peril. But that's not scientific, really. After the two of them parted ways, Dakota just stopped carrying the Time Shield around with him. It's not like he was going to be going back for him anymore. Thus, the older hims from the Bad Future didn't have it, and all of them poofed.
Okay, I'm mostly done explaining now.
But there is one thing to note. Time Shields don't only prevent alternate versions of oneself from disappearing. They can also prevent the erasing of someone whose existence was prevented.
Yeah, that didn't make much sense. Let's say... Elliot's existence was altered by someone going back in time and changing things, and now Elliot shouldn't exist. No one would remember him. But, he would still be there, and probably would still remember who he is. Why? Because his lead-lined stop sign acts as a Time Shield. It protects him. It's a similar situation to George Bailey in It's A Wonderful Life--he got his wish that he'd never been born, but he also got to see what it was like, and walk around in that world. He had some sort of... celestial time shield, I guess.
Whoo! That was a lot of scientific thinking for my brain to do. Did you follow me all the way through? If so, you are amazing. Now all I'm going to do is wonder what else might be a Time Shield.
Well, we know Elliot's stop sign is a Time Shield. I already noted that the picture of the island is probably also a Time Shield. There are some other possibilities. For example, Savannah's jewellery. Knowing her, it'll probably have multiple functions. Perhaps, after learning about the concept in her earlier days as a time agent, she bought the jewellery. That way, in case something was altered in the past, she'd still remember it and be able to fix it. I can't think of any others, can you? Let me know in the comments.
I suppose there are also other things that could shield one from time waves. Last Day of Summer (last episode of P&F) poses a lot of extra variables. Doofenshmirtz and Candace were the only ones who noticed that the day was looping over and over, and also were the only ones who could remember the things that disappeared. But that's also easy to explain. They were both right next to the Do-Over-Inator when it activated, and were probably caught in its radius (or something). Thus, they were shielded from the time waves.
Also, Time Shields don't protect one from having their memories wiped by a machine, or general amnesia. Just time-travel related things. Thought I'd add that.
(I would insert a pic of Buford going 'STOP SPLAINING!' but I couldn't find one.)
OH MY GOSH that was a lot. Sorry! I told you I was done with the scientific stuff, but I guess I lied. But now I'm really done with it.
Well, I told you I was going to talk about Milo Murphy's Law and time travel, and I did that. I mentioned I might talk about the past and the future. I talked about people going into the past, for sure. I talked about past episodes of past shows. What about the future?
Well, I know I'M looking forward to seeing that Phineas and Ferb/Milo Murphy's Law Crossover in the near future! And I'm planning on doing a lot more posts in the coming year, too. But for the present, I'll just say...
Happy New Year, everybody!