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Belief Revision: The Resubsumption Theory 349

A second key feature of the resubsumption hypothesis is that it links inten-
tional and material aspects of a switch in truth value. It situates truth value
assignment within real-time cognition instead of leaving it in the Platonic
heaven of idealizations and logical relations. Adjusting the utility estimate of
a belief is very different from evaluating the strength of evidence. However,
utility and truth are linked by the fact that a theory that is true tends to be
more useful than one that is false. Actions, judgments or inferences that rely
on an inaccurate theory will get a person into trouble more often than those
that are based on a more accurate theory. Such epistemic trouble takes many
forms: bad decisions, contradictions with other information sources, inabil-
ity to explain events or regularities, lost arguments, malfunctioning devices,
mistaken predictions, rejected journal submissions and so on. Utility is mod-
erated by feedback from the environment about the effectiveness of actions
derived from the theory, and effectiveness is in turn a function of veridicality,
so utility and truth are linked, if indirectly, via confidence.

Propagation of Change

A shift in the truth value of one belief will tend to propagate through the belief
base. In the words of W. V. Quine: “A conflict with experience at the periphery
[of a belief system] occasions readjustments in the interior of the field. Truth
values have to be redistributed over some of our statements. Re-evaluation of
some statements entails re-evaluation of others.…” 25
If the switched truth value is associated with a single, peripheral belief, it
will not propagate far and the change will be minor. If the altered truth value is
associated with an entire belief system or theory, the switch will have implica-
tions for all the beliefs of lesser scope that belong to that theory. There will be a
strong tendency to accept the component beliefs as true. The change might roll
through the belief system like a wave, presumably giving rise to the subjective
experience of conversion. For example, if I should come to believe that diet
does not matter, because a person‘s health is completely determined by his genes,
this would trigger a wave of changes throughout my belief system for health
and diet. The beliefs that fat is bad for you, chocolate is good for you and many
others would flip from true to false. On the other hand, I would be more dis-
posed to believe in claims about particular links between genes and diseases.
A change in truth value might also propagate upward through the belief
base, affecting the truth of any belief system of larger scope that draws on or
encompasses the changed belief or belief system. The change that occurs in any
one instance is massively contingent on the exact structure and content of the