Well, firstly the assumption that there’s a unique way of mapping a physical system to a particular function. Physical systems can be interpreted in many different ways.
Secondly, I think it’s a mistake to insist that we model subjunctive linking as logical counterfactuals. My memory isn’t perfect, but I don’t recall seeing a justification for this choice in the FDT paper, apart from “Wouldn’t it be convenient if it were true?”
I suspect this comes from the allergy of much of the LW crowd to philosophy. If you say that you’re dealing with logical counterfactuals, then looks like you’re dealing with mathematical formalisms, nevermind that it isn’t really a formalism until you pin down a lot more details, since there’s no objective fact of the matter of what it would mean for a function to be equal to something that it’s not.
It seems much more honest to just admit that you’re not yet at the formalisation stage and to follow the philosophical route of asking, “So what do we really mean by counterfactuals?”. And until you have a good answer to this question, you don’t want to commit yourself to a particular route, such as assuming that the solution must be some kind of formalism for dealing with non-classical logic.
A further point: We aren’t just trying to imagine that say f(x)=1 instead of 2 because we’re interested in this question in and of itself, but rather because we’re trying to figure out how to make better decisions. Throwing away the why is a mistake in my books. Even if we were only looking non-classical logics, we would be throwing away our criteria for distinguishing between different schemes. And at the point where we’re keeping around our why, then there’s no reason for reducing the question to a mere logical one.
In what ways is FDT broken?
Well, firstly the assumption that there’s a unique way of mapping a physical system to a particular function. Physical systems can be interpreted in many different ways.
Secondly, I think it’s a mistake to insist that we model subjunctive linking as logical counterfactuals. My memory isn’t perfect, but I don’t recall seeing a justification for this choice in the FDT paper, apart from “Wouldn’t it be convenient if it were true?”
I suspect this comes from the allergy of much of the LW crowd to philosophy. If you say that you’re dealing with logical counterfactuals, then looks like you’re dealing with mathematical formalisms, nevermind that it isn’t really a formalism until you pin down a lot more details, since there’s no objective fact of the matter of what it would mean for a function to be equal to something that it’s not.
It seems much more honest to just admit that you’re not yet at the formalisation stage and to follow the philosophical route of asking, “So what do we really mean by counterfactuals?”. And until you have a good answer to this question, you don’t want to commit yourself to a particular route, such as assuming that the solution must be some kind of formalism for dealing with non-classical logic.
A further point: We aren’t just trying to imagine that say f(x)=1 instead of 2 because we’re interested in this question in and of itself, but rather because we’re trying to figure out how to make better decisions. Throwing away the why is a mistake in my books. Even if we were only looking non-classical logics, we would be throwing away our criteria for distinguishing between different schemes. And at the point where we’re keeping around our why, then there’s no reason for reducing the question to a mere logical one.