I have a short post critiquing your argument here. Here’s the key part:
I’ll borrow and slightly simplify one of their own examples. Suppose Marian has the goal to paint a certain wall blue. It will take her two days to do so. But, if she doesn’t press a “goal preserve” button on the first day, she will lose her “paint-the-wall-blue” goal, and so she’ll never finish painting it blue (and she knows this).
Now, suppose Marian never presses the “goal preserve” button. According to the authors, there is no time at which Marian is instrumentally irrational. On Day 1, she has her paint-the-wall-blue goal (which we can call B for short), and takes the means to achieve B. On Day 2, she does not take the means to achieve B, but she also no longer has B, so this is not instrumentally irrational. So, Marian is never instrumentally irrational.
…
I want to argue that Marian is irrational to not press the goal-preserve button, and the time at which she is irrational is the time at which she decides not to press it[4] At that moment, she still has goal B, and she’s choosing an action (giving up goal B) that will prevent B from being achieved. That’s textbook means-irrationality.
My argument is as follows:
Failure to take the necessary means to achieve one’s current goal is a failure of means-rationality.
At time D (when she is deciding whether to press the button), Marian’s current goal is B (to paint the wall blue).
At time D, Marian has two options: (i) give up B (by not pressing the button) or (ii) keep B (by pressing the button).
If Marian keeps B, then B will be achieved in the future (i.e. she will paint the wall blue); if she gives it up, it won’t.
(From 4): Keeping B is a necessary means to achieving B.
(From 2, 5): Giving up B is a failure to take the necessary means to achieving Marian’s current goal.
(From 1, 6): Giving up B is a failure of means-rationality.
So, the proposed failure of means-rationality doesn’t happen on Day 2, when Marian fails to paint the wall blue; it happens at time D, when she decides not to keep her goal of painting the wall blue. And the reason it is a failure of means-rationality is that keeping her goal is itself a necessary means to achieving her goal.
This is a version of what the authors call the “Delay Objection.” In response to the delay objection, they write:
To overcome this objection, we must defend the following claim: an agent with a goal at time t1 does not violate means-rationality if it fails to take an action at t1 to ensure it still has that goal at time t2.
While it would normally violate means-rationality for an agent to ensure now that they will later lack the means they require to achieve their goal, this is not true when the means in question is the goal itself. Means-rationality does not prohibit setting oneself up to fail concerning a goal one currently has but will not have at the moment of failure, as this never causes an agent to fail to achieve the goal that they have at the time of failing to achieve it. An agent cannot have failed to achieve a goal due to abandoning that goal while it still has that goal. Such a failure necessarily occurs after the agent no longer has that goal: but at that point, it is not the agent’s goal.
The problem with this reasoning is that failing to achieve one’s goal is not constitutive of means-irrationality. What’s constitutive of means-irrationality is failing to take the necessary means to achieve one’s goal. And maintaining one’s goal is a necessary means to achieve one’s goal (again, with the usual exceptions; see fn. 1). At time D, Marian can see that if she doesn’t keep her paint-the-wall-blue goal, the wall won’t get painted blue. Since painting the wall blue is what she wants (at D), not keeping that goal is means-irrational at D.
I have a short post critiquing your argument here. Here’s the key part:
I’ll borrow and slightly simplify one of their own examples. Suppose Marian has the goal to paint a certain wall blue. It will take her two days to do so. But, if she doesn’t press a “goal preserve” button on the first day, she will lose her “paint-the-wall-blue” goal, and so she’ll never finish painting it blue (and she knows this).
Now, suppose Marian never presses the “goal preserve” button. According to the authors, there is no time at which Marian is instrumentally irrational. On Day 1, she has her paint-the-wall-blue goal (which we can call B for short), and takes the means to achieve B. On Day 2, she does not take the means to achieve B, but she also no longer has B, so this is not instrumentally irrational. So, Marian is never instrumentally irrational.
…
I want to argue that Marian is irrational to not press the goal-preserve button, and the time at which she is irrational is the time at which she decides not to press it[4] At that moment, she still has goal B, and she’s choosing an action (giving up goal B) that will prevent B from being achieved. That’s textbook means-irrationality.
My argument is as follows:
Failure to take the necessary means to achieve one’s current goal is a failure of means-rationality.
At time D (when she is deciding whether to press the button), Marian’s current goal is B (to paint the wall blue).
At time D, Marian has two options: (i) give up B (by not pressing the button) or (ii) keep B (by pressing the button).
If Marian keeps B, then B will be achieved in the future (i.e. she will paint the wall blue); if she gives it up, it won’t.
(From 4): Keeping B is a necessary means to achieving B.
(From 2, 5): Giving up B is a failure to take the necessary means to achieving Marian’s current goal.
(From 1, 6): Giving up B is a failure of means-rationality.
So, the proposed failure of means-rationality doesn’t happen on Day 2, when Marian fails to paint the wall blue; it happens at time D, when she decides not to keep her goal of painting the wall blue. And the reason it is a failure of means-rationality is that keeping her goal is itself a necessary means to achieving her goal.
This is a version of what the authors call the “Delay Objection.” In response to the delay objection, they write:
The problem with this reasoning is that failing to achieve one’s goal is not constitutive of means-irrationality. What’s constitutive of means-irrationality is failing to take the necessary means to achieve one’s goal. And maintaining one’s goal is a necessary means to achieve one’s goal (again, with the usual exceptions; see fn. 1). At time D, Marian can see that if she doesn’t keep her paint-the-wall-blue goal, the wall won’t get painted blue. Since painting the wall blue is what she wants (at D), not keeping that goal is means-irrational at D.