Wrong for themselves? How would we know that? Wouldn't we only know it's wrong when comparing it to our criteria of truth and how we see reality?
The wording was weird. What I meant to say was that person A could say that person B's view is wrong for themselves as person A. I other words, "It doesn't work for me, but it apparently works for you." Once upon a time, belief X may have worked for them, but later in life it no longer does, but for person B it does. The truth is relative to that person and the stages and situations they are in at the time. That's what I meant to say.
But why can't people say the other is wrong when (in the OP) it's talking about their theology?
Even saying "you are wrong about your interpretation" isn't challenging the person's conviction. Maybe the other has the wrong interpretation and the only way he can recognize it is if someone pointed it out. (As a therapist would with cognitive distortions). Of course, it depends on the relationship both parties have, possibility and their patience level.
You brought up the Trinity doctrine later as an example. If someone says that the Trinity teaches there are three gods, that in fact would be a wrong statement. It does not teach that. But, if they were to say that you were wrong for believing God is a Trinity, because that's not how they believe, that is not an objective statement. That is a matter of perception and belief, not objective fact. The best you can say is I don't believe that way myself. That view of God is wrong to me.
It makes me think of what the Apostle Paul said in Romans 14:5. "
One man esteemeth one day above another: another esteemeth every day alike. Let every man be fully persuaded in his own mind." That pretty much captures the whole thing right there. In other words, who are you to say it's wrong for them?
Its by our own standards. For example, a abrahamic god believer may tell a non-believer he or she is wrong about god's non-existence.
That is fine because it's just telling the NB his opinion about the other person's conclusion of god's existence. His parameters or criteria would be his religious god-supporting theology. It would make sense that he would see the other is wrong.
Likewise, if someone believed in reincarnation and the other heaven, setting aside personal preference in language, saying the other is wrong isn't rude but saying it just doesn't jive with their personal view and criteria of reality. Which is perfectly fine in a civilized conversation.
But saying you are wrong to that person, is a voice of authority speaking on behalf of God, if you are talking about things of a religious nature. It's like the young upstart Christian who tells someone they are going to hell because they haven't been baptized properly according to their theology.
That is not perfectly fine. They are presuming they speak for God, and they often come right out and say just that, "It's not my words, but God's!" That's when I cite Jesus telling them to judge not, lest they be judged. That is the context of when saying the other is wrong, is wrong itself. "Who are you to judge another man's servant?"
I can see why you say it presumes you are god (or in general, it presumes we know everything). Wouldn't depend on the context though?
Saying you're wrong doesn't mean we know everything. It's just voicing our opinion based on our criteria that conflicts with another.
You can say they are wrong, if you know they are, such as if they claim America was discovered by Neil Armstrong for instance. That's just wrong. Saying the election was stolen, is wrong, because it can be proven it was not quite easily. When it comes to the nature of God however, that's a lot less concrete and verifiable.
I assume you've heard the story of the blind men and the elephant? All of them were proclaiming the truth about the elephant, that none of them could see.
Blind men and an elephant - Wikipedia
But the idea is that if you believe god exists and the other person does not, for you (I think?) if god is a fact/like math, by default if someone else says opposite, they would be wrong.
Saying that depends on the person, but wrong nonetheless.
Not necessarily. Both can be right. Sometimes in life there is more than one right answer, even when they are contradictory answers. Light can in fact be both a particle and a wave for instance.
When it comes to God, God can both exist and not exist at the same time. Such is the nature of nonduality. So the theist and the atheist are both right, and both wrong for insisting it's one versus or other. Instead of an 'either/or' reality, it can be a 'both/and' reality.
I related right and wrong with moralities (how we see reality in respect to others) rather than fact and fiction or being correct or incorrect as in math.
But morality is not a matter of absolutes. It's a matter of situations and degrees. Is it wrong to steal medicine to save someone who is dying, for instance?
That's actually a question on the stages of moral development test that developmental psychologists ask. That falls under the postconventional stages of morality, where black and white, wrong vs. right answers are thrown into doubt.
Kohlberg’s Stages of Moral Development | Education, Society, & the K-12 Learner.