I think you need to understand that in terms of doxastic voluntarism. The Church holds that faith is voluntary, so that people can reasonably be praised or blamed for what they believe. They may not say it explicitly about other kinds of belief, but if they are right about religious beliefs, it would probably also be true that accepting or rejecting the theory of evolution (and any other similar thing) is also voluntary.
Given that account of belief, saying “you are obliged to say that this is definitely true and that this other thing is at least not definitely true,” is a statement about the choices you should make. You should choose to say (according to Pius XII), “Christianity comes from God,” and “Christianity definitely comes from God,” but not (according to Pius XII), “The theory of evolution applied to human beings is definitely true.”
Because it’s a question of choices, probability is not really relevant one way or another (except in the sense that the probability that something is true might be one reason that should affect whether or not you say something). That is why I gave the example of someone who estimates the chance of his beliefs being right, based on the evidence, to be about 50%. But despite that he chooses to say “this is simply true,” probably based on various moral considerations. Kind of like you might want to believe your brother about something rather than saying he is lying, not because of strong evidence for that, but because it’s hurtful to say “you’re lying.”
If this account is correct, the reason you can’t translate statements like that into statements resembling claims about probability is because that is simply not what they are about.
Rationalists say many things which have similar moral implications, and which don’t ultimately make a lot of sense apart from a similar doxastic voluntarism (e.g. “you ought to update on evidence,” which implies that you can and should choose to do so), but most people don’t accept an account like this explicitly. If you don’t accept doxastic voluntarism, you should simply say that the Catholic Church’s statements about such things are presuming an incorrect theory of belief, and just don’t make any sense apart from that theory.
(I agree with doxastic voluntarism, so such statements do make sense to me, whatever I happen to think about them on an object level.)
Rationalists say many things which have similar moral implications [...] e.g. “you ought to update on evidence”
When I say “you ought to update on evidence” I’m fairly sure I am neither endorsing doxastic voluntarism nor making a claim about the morality of updating (or not) on evidence. Rather, I mean that if you update appropriately on evidence then your beliefs will, over time, tend to grow more accurate compared with the beliefs you would hold if you didn’t update appropriately on evidence, and that this is likely to benefit whatever goals you may have. (I might add that it benefits other people for your beliefs to be accurate, so there is some moral import to whether you update on evidence, but that’s not what I would mean by “ought”.) Is it a pointless thing to say if we don’t get to choose what we believe? Not if we have more choice about what overall strategy to use when adjusting our beliefs than we have about individual beliefs, which I think may well be the case.
(As to the actual question of doxastic voluntarism, I think it’s clear that it comes in degrees and that the truth isn’t right at either extreme. I don’t believe either of us could, right now, decide to believe that grass is pink and forthwith start doing so; but I’m pretty sure either of us could incline ourselves more toward believing (say) that Charles Dickens was born in 1834 simply by repeating “Charles Dickens was born in 1834” in a confident tone of voice fifty times. Choose another example if you happen already to have a confident opinion about whether Dickens was born in 1834.)
I am fairly sure that many rationalists do in fact make claims about updating on evidence with moral implications, even if you do not intend those implications yourself. But in any case, even your response implies a certain degree of voluntariness, if it is possible to adopt an overall strategy of adjusting our beliefs; if it were totally involuntary, we could not affect the strategy (and in fact you agree in the second part that it is not totally involuntary.)
I agree that in the way people ordinarily mean it, I could not start to believe that grass is pink. But I also could not go and kill myself right now. That doesn’t make not killing myself involuntary, since the reason is that I think it would be bad to kill myself. The case of the grass might be different, and it might be impossible to start to believe that in a stronger sense. In other discussion of this issue someone compared it to holding your hand in a fire until it is burned off; that might well be a physical impossibility, not just a question of thinking that it is bad.
But even in the case of holding your hand in a fire, I would see that as a certain kind of desire (to pull your hand away), even if it is one that we cannot resist with our conscious desires, and the case of belief seems pretty similar. This might just be a question of how much you are willing to strain an analogy.
It’s not as if “belief” is a name for one objective thing in the world which is either there or not. There are a whole bunch of things, words, actions, thoughts, and feelings, and we call various patterns of these things a “belief.” Some of these things are voluntary and some are not. Simply for consistency I choose to call the voluntary parts of that pattern “belief” and exclude the other parts, at least when there is competition between them. According to this way of speaking, I could choose to believe that Dickens was born in 1834, even right now, if I had a motive to do so. But that would not affect the involuntary parts of my assessment, and you might prefer to call it something else (e.g. “belief in belief”).
I think you need to understand that in terms of doxastic voluntarism. The Church holds that faith is voluntary, so that people can reasonably be praised or blamed for what they believe. They may not say it explicitly about other kinds of belief, but if they are right about religious beliefs, it would probably also be true that accepting or rejecting the theory of evolution (and any other similar thing) is also voluntary.
Given that account of belief, saying “you are obliged to say that this is definitely true and that this other thing is at least not definitely true,” is a statement about the choices you should make. You should choose to say (according to Pius XII), “Christianity comes from God,” and “Christianity definitely comes from God,” but not (according to Pius XII), “The theory of evolution applied to human beings is definitely true.”
Because it’s a question of choices, probability is not really relevant one way or another (except in the sense that the probability that something is true might be one reason that should affect whether or not you say something). That is why I gave the example of someone who estimates the chance of his beliefs being right, based on the evidence, to be about 50%. But despite that he chooses to say “this is simply true,” probably based on various moral considerations. Kind of like you might want to believe your brother about something rather than saying he is lying, not because of strong evidence for that, but because it’s hurtful to say “you’re lying.”
If this account is correct, the reason you can’t translate statements like that into statements resembling claims about probability is because that is simply not what they are about.
Rationalists say many things which have similar moral implications, and which don’t ultimately make a lot of sense apart from a similar doxastic voluntarism (e.g. “you ought to update on evidence,” which implies that you can and should choose to do so), but most people don’t accept an account like this explicitly. If you don’t accept doxastic voluntarism, you should simply say that the Catholic Church’s statements about such things are presuming an incorrect theory of belief, and just don’t make any sense apart from that theory.
(I agree with doxastic voluntarism, so such statements do make sense to me, whatever I happen to think about them on an object level.)
When I say “you ought to update on evidence” I’m fairly sure I am neither endorsing doxastic voluntarism nor making a claim about the morality of updating (or not) on evidence. Rather, I mean that if you update appropriately on evidence then your beliefs will, over time, tend to grow more accurate compared with the beliefs you would hold if you didn’t update appropriately on evidence, and that this is likely to benefit whatever goals you may have. (I might add that it benefits other people for your beliefs to be accurate, so there is some moral import to whether you update on evidence, but that’s not what I would mean by “ought”.) Is it a pointless thing to say if we don’t get to choose what we believe? Not if we have more choice about what overall strategy to use when adjusting our beliefs than we have about individual beliefs, which I think may well be the case.
(As to the actual question of doxastic voluntarism, I think it’s clear that it comes in degrees and that the truth isn’t right at either extreme. I don’t believe either of us could, right now, decide to believe that grass is pink and forthwith start doing so; but I’m pretty sure either of us could incline ourselves more toward believing (say) that Charles Dickens was born in 1834 simply by repeating “Charles Dickens was born in 1834” in a confident tone of voice fifty times. Choose another example if you happen already to have a confident opinion about whether Dickens was born in 1834.)
I am fairly sure that many rationalists do in fact make claims about updating on evidence with moral implications, even if you do not intend those implications yourself. But in any case, even your response implies a certain degree of voluntariness, if it is possible to adopt an overall strategy of adjusting our beliefs; if it were totally involuntary, we could not affect the strategy (and in fact you agree in the second part that it is not totally involuntary.)
I agree that in the way people ordinarily mean it, I could not start to believe that grass is pink. But I also could not go and kill myself right now. That doesn’t make not killing myself involuntary, since the reason is that I think it would be bad to kill myself. The case of the grass might be different, and it might be impossible to start to believe that in a stronger sense. In other discussion of this issue someone compared it to holding your hand in a fire until it is burned off; that might well be a physical impossibility, not just a question of thinking that it is bad.
But even in the case of holding your hand in a fire, I would see that as a certain kind of desire (to pull your hand away), even if it is one that we cannot resist with our conscious desires, and the case of belief seems pretty similar. This might just be a question of how much you are willing to strain an analogy.
It’s not as if “belief” is a name for one objective thing in the world which is either there or not. There are a whole bunch of things, words, actions, thoughts, and feelings, and we call various patterns of these things a “belief.” Some of these things are voluntary and some are not. Simply for consistency I choose to call the voluntary parts of that pattern “belief” and exclude the other parts, at least when there is competition between them. According to this way of speaking, I could choose to believe that Dickens was born in 1834, even right now, if I had a motive to do so. But that would not affect the involuntary parts of my assessment, and you might prefer to call it something else (e.g. “belief in belief”).