The shared, tacit assumptions that enable communication and cooperation within a group, maintained by collective confirmation. When everyone in a community starts from the same axioms and continually reinforces them through discourse, the axioms become "common ground"—so obvious they need not be stated. This bias is functional: it reduces negotiation costs and enables coordinated action. It is also a prison: it makes the group's foundational premises invisible and unassailable from within.
Confirmation Bias of Common Ground Example: In a corporate meeting, everyone confirms that "shareholder value" is the ultimate goal. This common ground is never debated; it's the platform upon which all other debates happen. An outsider asking "Why maximize shareholder value?" is met with confused silence—they've violated the Confirmation Bias of Common Ground. The group's bias is so deeply shared they've forgotten it's a bias.
by Dumu The Void February 11, 2026
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