So let’s start with regular counterfactuals. What are they? Do they exist in the universe itself? Unless you’re a modal realist (ie. David Lewis and his clones) the answer is no. Given the exact state of universe and an agent, the agent can only make one decision*.
Yudkowsky and Deutsch’s MWI has exactly the same implications as Lewisian modal realism in this regard. (One of the basic problems with this ).
Quantum mechanics allows this to be a probability distribution, but then it’s just probabilistically deterministic instead, so it only complicates the issue without really changing anything
It changes something: it allows real counterfactuals in a single universe. There is a (contentious) argument that free will based on quantum indeterminism isn’t free enough to be considered genuine free will because it is still constrained to probability distributions...but , whether true or false, that isn’t relevant to the topic at hand, the existence of real counterfactuals. Real counterfactuals don’t depend purely on some fairly “thick” concept of free will, they can follow from indeterminism alone. If it really was the case that a coin toss could have gone differently , then the case where it did is a real counterfactual.
(But not an actual counterfactual. MR and MW have the further implication that all outcomes are actual from their own perspective).
P.S If the overall point is that there is not and should be a single notion counterfactuals, I would agree .. so long as real counterfactuals are included!
Yudkowsky and Deutsch’s MWI has exactly the same implications as Lewisian modal realism in this regard. (One of the basic problems with this ).
It changes something: it allows real counterfactuals in a single universe. There is a (contentious) argument that free will based on quantum indeterminism isn’t free enough to be considered genuine free will because it is still constrained to probability distributions...but , whether true or false, that isn’t relevant to the topic at hand, the existence of real counterfactuals. Real counterfactuals don’t depend purely on some fairly “thick” concept of free will, they can follow from indeterminism alone. If it really was the case that a coin toss could have gone differently , then the case where it did is a real counterfactual.
(But not an actual counterfactual. MR and MW have the further implication that all outcomes are actual from their own perspective).
P.S If the overall point is that there is not and should be a single notion counterfactuals, I would agree .. so long as real counterfactuals are included!