A: Why not see what can be said for the strongest position – Mary not only did not sin, but could not have.
B: But this is untenable: she had the same gifts as Adam, and Adam was certainly able to sin; and it’s impossible to be human and lack the ability to sin. But what’s your argument?
A: To set it up, consider these difference senses of “can”. If I say an axle can drive the car and the axle can rub on the bearing and light the car on fire, is the sense of “can” the same?
B: Yes, they’re both possibilities for the axle.
A: But one “can” arises only from a defect.
B: So that’s your argument: if something can happen because of a malfunction or sabotage, then, in the absence of this, it can’t happen.
A: Isn’t that right, though? We first sin because we’re surprised and slip or get carried away, or because the first things we know aren’t the best things, or because we can’t see how to combine our autonomy with our need for discipleship, etc.
B: But you solve one problem only to make the other more acute. If Mary couldn’t sin then how could Adam?
A: I’m not sure. I want to keep the idea that when something “can” happen only because of a defect, then removing the defect removes the “can” also. But then I’m stuck defending the idea that Adam could not sin, but did.
B: You could just deny that sin arises only out of defect.
A: No. This leaves open the possibility of sin even in the eschaton and even among the blessed. But then this story of sin and repentance never needs to come to an end. Sin is an act, and actions follow from a previous order or disorder in the subject.
B: Maybe the “can” you’re targeting can’t be captured in the way you’re trying to capture it.
A: Why not?
B: All your examples of what “can” happen were really just probabilities. A faulty axle “can” ignite the gas tank in the same way a fair coin can come up heads or tails. But the moral “can” is not like this. The choice between good and evil is not merely a calculation of possible outcomes.
A: I don’t get it.
B: Denying that someone can sin is not the same thing as saying their actions are logically necessary.
A: But I can’t see the way forward from here. I can’t decide if we’ve made a basic mistake.
B: Let’s leave off for now then.