Echo chambers, algorithmic recommendations, and powerful filters all but guarantee multiple realities for different people. If all you see are facts X, Y, and Z, then those facts are as real and true as someone else's facts A, B, and C. I have family members and friends who live in seemingly totally alternate universes, dominated by what I see as conspiracy theories, pseudoscience, and a cultural persecution complex. But as they describe it: it's I who live in a media-manufactured alternate reality characterized by trust in institutions, corruption, and a false belief in science and data.
What everyone is missing is: both universes might as well be correct, to the observer. It's like measuring what speed someone is going in two different relativistic frames of reference. You can both be right and come up with different numbers. It's a tough problem to solve. We can't solve it by just pointing at the out-groups and saying "ha-ha how stupid are they for believing in rubbish!" They are just not going to be convinced by someone who believe a totally different set of facts.
What everyone is missing is: both universes might as well be correct, to the observer. It's like measuring what speed someone is going in two different relativistic frames of reference. You can both be right and come up with different numbers. It's a tough problem to solve. We can't solve it by just pointing at the out-groups and saying "ha-ha how stupid are they for believing in rubbish!" They are just not going to be convinced by someone who believe a totally different set of facts.