Page 311 - Deep Learning

294 Conversion

main use of a belief is to guide action, particularly in unfamiliar situations. if i
believe that my destination lies to the left, i am likely to make a left-hand turn
at the relevant intersection, even if i have never traveled the intended route
before; the action is implied by the belief. reasoning from belief to action is
called practical inference or practical reasoning in philosophical discourse. it is
a high-level process that imposes considerable cognitive load – imagine decid-
ing which actions are implicated by the facts about global climate change – but
such reasoning can nevertheless help reduce uncertainty in novel or unfamil-
iar situations. Beliefs typically have some level of abstraction, so their applica-
tion involves replacing variables with the objects and events in the situation at
hand, which gives beliefs a schema-like character. To be applied, a belief has to
be retrieved from long-term memory. The person’s representation of the situ-
ation or task at hand is the main retrieval probe.
A person’s belief base grows over time. The main triggering condition for
the formation of a new belief is that new information knocks on the doors of
perception and asks to be let in. opening our eyes automatically triggers per-
ceptual processes that encode what is in front of them. if someone speaks to
us in a language we know, it is impossible to will ourselves not to comprehend
what the person says. if we see it or hear it, we encode it. in addition, we infer
new propositions from prior propositions. Perception, discourse comprehen-
sion and reasoning generate a steady flow of new propositions. The Principle
of Ubiquitous Encoding is a convenient verbal handle for this fact. The new
propositions are created in working memory, remain active for some variable
amount of time and then fade. A significant subset of those propositions is
stored in long-term memory. research into the psychology of memory has
identified some of the factors that control the probability that any one piece of
information becomes encoded into long-term memory, but the details are not
important here. 5
encoding of propositional content is not necessarily associated with assent,
but most new propositions do in fact arrive in working memory marked as
true. Philosophers write as if doubt is the natural state of mind and as if only
a small number of propositions are ever accepted as true, and then only if
there are particular reasons to do so. This is a good description of the belief
maintenance practice of philosophers. Their lengthy training enables them to
overrule the natural disposition of human beings to operate in the opposite
way: adopt information as true unless there is reason for doubt. 6
Consider visual perception. As the proverb has it, seeing is believing.
7
Forming a belief via perception is to construct a mental representation of the
relevant state of affairs and also to decide that this representation is veridical.