Who Needs Emotions? The Brain Meets the Robot

214 robots
Primitive sensors provide information about some aspect of the world
simply because the information provided varies as the world changes (another
example of sets of counterfactual conditional statements). Insofar as
the sensors meet the need of providing correct information, they also serve
a desire-like function, namely, to “track the truth” so that the actions initiated
by other desire-like states serving other needs can be appropriate to
meeting those needs. In such cases, the state B will include mechanisms for
checking and maintaining the correctness of B, in which case there will be,
as part of the mechanisms producing the belief-like state, sub-mechanisms
whose operation amounts to the existence of another desire-like state, serving
the need of keeping B true and accurate. In a visual system, this could
include vergence control, focus control, and tracking.
In these cases, B has a dual function: the primary belief-like function of
providing information and the secondary desire-like function of ensuring that
the system is in state B only when the content of B actually holds (i.e., that
the information expressed in B is correct and accurate.) The secondary function
is a means to the first. Hence, what are often regarded as non-desirelike
states can be seen as including a special subclass of desire-like states.
We are not assuming that these states have propositional content in the
sense in which propositional content can be expressed as predicates applied
to arguments or expressed in natural language. On the contrary, an insect
which has a desire-like state whose function is to get the insect to find food
need not have anything that could be described as a representation or encoding
of “I need food.” Likewise, the percepts and beliefs (belief-like states) of
an insect need not be expressible in terms of propositions. Similar comments
could be made about desire-like and belief-like states in evolutionarily old parts
of the human information-processing architecture. Nevertheless, the states
should have a type of semantic content for which the notion of truth or
correspondence with reality makes sense (Sloman, 1996).
In describing states as having functions, we imply that their causal connections
are to some extent reliable. However, this is consistent with their
sometimes being suppressed or overridden by other states in a complex
information-processing system. For instance, although it is the function of
a belief-like state to “track the truth,” a particular belief may not be removed
by a change in the environment if the change is not perceived or if
something prevents the significance of a perceived change being noticed.
Likewise, the desire to achieve something need not produce any process
tending to bring about the achievement if other, stronger desires dominate,
if attention is switched to something else, or if an opportunity to achieve
what is desired is not recognized. So, all of these notions have interpretations
that depend heavily on complex collections of counterfactual conditionals
being true: they are inherently dispositional concepts (see also the