On the most fundamental level: For everyone. That’s because every world-view bogs down to a logical system and all logical systems are grounded in circular reasoning, paradox, or assumptions not provable in that system.
People believe in all kinds of things, e.g. that the judge who’s sentencing you to prison is more than a human in fancy clothes. Or that the social reality that gives them that power doesn’t exist. Both stances are, ultimately, insane, and so are we all.
EDIT: ITT: Cargo cultists not understanding what science is (a process) and isn’t (proof of anything).