If something is probable, you have to ask what makes it probable. We measure quantum probabilities by the number of times a given experiment yields a given outcome. Say there's an observable and when you measure it, outcome Lefty happens 90% of the time and outcome Righty happens 10% of the time. On MW, both of those happen, and 2 conscious beings result. What makes "being Lefty" more probable? Are there more Lefties than Righties? Or will outcome Lefty happen more often than outcome Righty? The answer to both is no, you get two every time. They're two conscious minds, but both continuous with the old you in the same way.
I'm not sure I understand. Suppose the mind throws a thousand dices. We measure two possible events: if there is at least a dice with a 1 on it, and if all dices have a 1 on it.
There are 6^1000 possible conscious minds. We call Lefty to the one that sees the first, very probable event. We call Righty to the one that sees the second, very unprobable event. There is actually only one Righty, but there are many, many Lefties. So it's actually a lot more probable to be a Lefty than to be a Righty. I think this works too with any other kind of event you could imagine (at least in a discrete (meta?)world, I'm not sure how you could have continuous probabilities if there are only discrete amounts of worlds available, or if you can have continuous amounts of worlds instead).
How does what you say work in this example? Why would both events have the same probability?
I don't know about QM more than the very, very basics, so please excuse me if I'm not understanding something very fundamental here.
On MW, there are an infinite number of worlds at time t if an infinite number of quantum outcomes has occurred by time t. Anyway, it sounds like you're thinking this: There are an infinite number of worlds. A quantum event happens in many of them. There are more worlds where it happens than where it doesn't. Therefore this event is more likely.
But that's not MW. MW says that something happens, and when it happens, you get one world for each outcome. There's a problem here because what these outcomes are depend on the basis you write the wave function in, but that's a different issue. It's certainly not saying that there are an infinite number of worlds, each with a determined series of events, and we have probabilities because some of those worlds are more numerous than others. That's modal realism, as I said in a comment above.
By the way, that doesn't just raise its head in the context of quantum mechanics. It only does because it gives us reason to believe that it's physically possible that things could've been different than they actually are. But it seems possible-period that things could've been different, even if physics was deterministic. Even though it might've been physically determined that I went to the grocery store yesterday, it's certainly possible tout court that the whole universe had gone differently, and I could've gone to Fenway to see the Sox game instead. But does that mean that there's an alternate universe where my otherworldly counterpart went to Fenway? Isn't there a simpler explanation for why that's possible? QM has alternatives, like the Bohmian and GRW theories, which are far more plausible as well.
