So, if “I climb the nearby mountain” is an action, and “I don’t climb the nearby mountain and the weather is sunny” is an outcome, it must be possible to create a scenario where climbing the nearby mountain has an 100% chance of resulting in not climbing the nearby mountain, and the weather being sunny.
Okay, but this action/outcome combination is logically impossible because it would require both climbing and not climbing the mountain. According to Jeffrey’s theory, “I don’t climb the nearby mountain and the weather is sunny” can’t be an outcome. Because, if is an action, only events of the type and are are outcomes, but or are not. This makes sense, since and form a logical partition of , i.e., they are 1) mutually exclusive and 2) jointly logically equivalent to .
However, this is not the case if we (unlike Jeffrey) regard outcomes as consequences, since consequences generally don’t imply their causes (including actions). The same set of macroscopic end states (outcomes) could have been produced by different initial states (causes). This has to do with the general increase in entropy over time, a basic fact about causality. Stirring or shaking a drink are two different actions, but they may result macroscopically in the exact same causal outcome. Likewise, the outcome of a broken egg doesn’t imply the action which broke it.
In that realistic view, possible outcomes are not jointly logically equivalent to their actions, which would mean two agents who assign the same expected utilities to the outcomes of a scenario need not assign the same utility (or probability) to their corresponding actions. They may inherently like some action for its own sake, and that needn’t be reflected in different evaluations of the outcomes—in contrast to Jeffrey’s theory, where the “outcomes” always imply their actions.
Consequentialism is also not as clearly false about people as you make it out to be (although it is false). “I climb the nearby mountain” is clearly not an action that can be taken in an arbitrary situation, whereas we are assuming that the set of available actions is exactly the same in all scenarios. What is always available is some discretization of the set of possible signals we can send to our muscles at some instant.
I think pure “muscle signals” is almost never what is meant in decision theory when talking about “actions”. An action is usually something like “taking an umbrella”, which is not available always. And strictly speaking, someone might have a stroke or a temporary paralysis and lose some of his muscle signals.
Moreover, even for actual muscle signals, someone might simply have a preference for moving his legs in some situation (someone after a long flight, say, or a dancer, or an excited child), apart from any expected consequences/outcomes. Which would already violate consequentialism.
(I agree that climbing a mountain is not usefully described as an action if there is a realistic chance of failure, in which case it would have to be modeled as an outcome.)
Okay, but this action/outcome combination is logically impossible because it would require both climbing and not climbing the mountain. According to Jeffrey’s theory, “I don’t climb the nearby mountain and the weather is sunny” can’t be an outcome. Because, if
However, this is not the case if we (unlike Jeffrey) regard outcomes as consequences, since consequences generally don’t imply their causes (including actions). The same set of macroscopic end states (outcomes) could have been produced by different initial states (causes). This has to do with the general increase in entropy over time, a basic fact about causality. Stirring or shaking a drink are two different actions, but they may result macroscopically in the exact same causal outcome. Likewise, the outcome of a broken egg doesn’t imply the action which broke it.
In that realistic view, possible outcomes are not jointly logically equivalent to their actions, which would mean two agents who assign the same expected utilities to the outcomes of a scenario need not assign the same utility (or probability) to their corresponding actions. They may inherently like some action for its own sake, and that needn’t be reflected in different evaluations of the outcomes—in contrast to Jeffrey’s theory, where the “outcomes” always imply their actions.
I think pure “muscle signals” is almost never what is meant in decision theory when talking about “actions”. An action is usually something like “taking an umbrella”, which is not available always. And strictly speaking, someone might have a stroke or a temporary paralysis and lose some of his muscle signals.
Moreover, even for actual muscle signals, someone might simply have a preference for moving his legs in some situation (someone after a long flight, say, or a dancer, or an excited child), apart from any expected consequences/outcomes. Which would already violate consequentialism.
(I agree that climbing a mountain is not usefully described as an action if there is a realistic chance of failure, in which case it would have to be modeled as an outcome.)