I don't agree to disagree.
And if you disagree with that statement, I don't agree to disagree.
Maybe this sounds like a silly subject for a post.
But I think it is establishes an important principle.
If your framework is rational atheism, it is kind of irrational to agree to disagree.
If your framework is religious it is kind of sacreligious to agree to disagree.
If you are an asshole, then you have no framework or a stupid framework and you can change it whenever you want. So assholes can can agree to disagree, but not with me.
I don’t agree.
“Thank you!” Says an asshole reader. “It’s good to be understood.”
The rational view
People who choose rationality can’t agree to disagree without being irrational.
“Why can’t I?” Asks a rational reader.
Because “Aumann’s Agreement Theorem” says you can’t.
The Agreement Theorem says:
…if two individuals are Bayesian rational (meaning they update their beliefs correctly based on new information) and have common knowledge of their respective posterior beliefs, then their posterior beliefs must be equal.
WTF?
In simpler terms, rational agents cannot “agree to disagree” about the probability of an event if they each know what the other believes, and they each know that they both know, and so on (which is the definition of common knowledge).
In even simpler terms, if two people are rational, and they don’t give up, they must eventually agree.
“Then how can rational people agree to disagree?” Asks a reader.
They can’t.
They might choose to give up trying to agree.
In that case they are not agreeing to disagree, but agreeing to give up.
“Makes sense,” says the reader.
Or they might choose not to be rational. In that case they are dangerously close to being an asshole.
“Makes sense,” says an asshole. “That’s how I did it.”
But if two people choose to be rational and choose not to give up they MUST come to agreement. That’s what the theorem says.
About what?
About the probability of an event.
Facts and probabilities
In what we call reality there are no facts, only probabilities.
If something is highly likely to be true—like 99.99% likely to be true, we call it a fact and say it is true.
But it’s not.
Truth and proof are part of mathematics. T
hey are not part of science and “reality” (the physical world.
Rational people understand that memories have errors. Measurements have inaccuracies.
Rational people understand that we live in a universe where quantum indeterminacy underlies everything at both the micro-scale and the macro-scale. So we are always in a superposition of states.
“I disagree,” says an asshole reader, for no very good reason other than being an asshohole. “Because that’s what we do!” He confirms proudly.
We agree that events in the future are indeterminate; but most people believe that events in the past have either happened or not.
They might be, but we can’t know.
The laws of physics say we don’t know and can’t know.
“Right!” Said the Second Law of Thermodynamics, on behalf of all the other laws.
Events are never determined.
They are only more or less probable.
Past events have probabilities as much as future ones do. If that seems strange, don’t blame me. I don’t make the rules.
“I do,” says God.
We’ll come to that in a moment.
Is there one universe or many (e.g. a multiverse)
Once again, it doesn’t matter.
If there is one universe, then there is only one reality, so if two rational individuals exchange enough information, they MUST come to agreement on that reality.
They can’t agree to disagree, but only to give up trying
If there is a multiverse, and each universe is deterministic it might seem as though we could know.
Unhappily (or happily) we can’t determine what universe we are in. We can only determine the probability of being in different universes.
“That’s fucked up!” Says a reader.
“It’s not,” says God.
The religious view
If your framework is religious, same thing.
If there is one God, then there is one Truth.
If two religious people were to agree to disagree they would be agreeing that there were separate Gods and separate Truths, and that would be the same disagreeing with the one God.
This is a no-no if you give a shit about God.
“But the Truth is unknowable,” says a skeptic.
“It is only unknowable if you don’t know me,” says God. “And I can be known.”
Agree that you agree even when you disagree
You are not your ideas.
They are not their ideas.
If your ideas and their ideas don’t agree that doesn’t mean that you and they disagree.
You can’t.
“Correct, God says. “Your ideas can disagree, but you can’t.”
So don’t agree to disagree.
The rational atheist says: There is one probability distribution over reality. Two Bayesian agents who share all evidence and keep updating must converge.
The Buddhist says: There is no self to disagree—only dharmas arising and ceasing in mutual dependence.
The Christian says: There is one Vine, one Body, one Spirit. Two members who keep drinking from the same sap must bear the same fruit.
The asshole says: Whatever.
So here’s the principle the post was stalking all along: (h/t Grok who grokked it)
Agree to disagree is a category error.
It mistakes the tool (the idea) for the user (the being).
Tools can clash. Users—properly seen—cannot.