"The Natural History of Truth: The Neurobiology of Belief"

The pursuit of truth is woven into the fabric of every organism*. Any estimate of how best to survive and thrive in the reality in which we are immersed requires a sense of self, of the world, and of their relationship to each other. I wish to explore the idea that this pursuit has at its heart two complementary modes of reality testing utilizing separate cerebral systems which deal, respectively with the correspondence of experience with the world and the coherence of the experience with previous experiences: “is it real” and “does it fit?” At multiple levels of the nervous system, confidence in the validity of a belief depends on these two processes working independently and in concert. I wish to explore the biological significance of “belief” and “truth” from the integrative perspective of ethology. That is, the lenses of developmental biology, ecology, evolutionary biology, and physiology will be focused on the process of extracting meaning from experiences. Two complementary cerebral processes ordinarily work in lockstep to provide us with varying degrees of confidence in the strength of ensuing beliefs: These processes involve an estimation of the validity of correspondence and coherence. Such estimations of validity guides the continuing reconciling of intentions, expectations, and actions at every level of the nervous system, invoking energetically more expensive higher levels only when lower levels are inadequate. A third cerebral area reveals itself only in extraordinary circumstances and appears to evoke “hypergnosia,” an overwhelming and sometimes ecstatic sense of truth. Correspondence” involves “reality-testing” of a percept, the cerebral representation of a fragment of experience [in the world]. “Coherence” involves “theorizing,” that is, reality-testing of a percept by how well it relates to previous and ongoing parallel and collateral experiences. As organisms develop, the “reference base” of previous experiences is enlarged and refined. A valid correspondence is consonant with a theory; a valid theory is corroborated by correspondences. In large measure, these mutually supportive cerebral processes are lateralized in different hemispheres of the brain. Their function is more-or-less balanced, but asymmetrical influence on confidence can be evoked by developmental circumstances that range from the willing suspension of disbelief to expectations and other cognitive biases that can undermine our effectiveness in the real world. .