A classic example of this dilemma can be found in ant foraging strategies
[Sumter & Beekman, 2003]: an individual ant has the choice either to follow a
pheromone trail left by other ants that leads to a known food source, or to deviate
from the trail and possibly discover a new source. If ants would always follow
existing trails, food sources would eventually get exhausted and the ants would die of
hunger. If ants would never stick to the trail, on the other hand, they would each time
again spend most of their time wandering around aimlessly until they happen to run
into a food source, so that on average they would only recover a fraction of the food
that they would get with a more exploitative strategy. In practice, ants follow the trails
most of the time (exploitation), but with a small probability of deviating from the trail
so that they could potentially discover a new source (exploration). The value of this
deviation parameter has probably been set by evolution so as to optimize the long-
term fitness of the ant colony.
An agent trying to maximize its fitness will therefore need to apply a judicious
combination of regulation (moving away from known disturbances), exploitation
(moving towards known affordances) and exploration (moving into the unknown).
Together, these steering mechanisms determine the process of navigation. Like the
great navigators in the past, navigation requires correcting any unfavorable deviations
from the present course of action (regulation), while at the same time further setting
out or adjusting this course of action so as to most efficiently exploit observed
affordances, while still maximizing the chances of discovering new affordances
(exploration). The eventual trajectory of a navigator is essentially unpredictable:
while its initial aim or direction may be clear, positive and negative diversions will
upset the smooth advance and are likely to create deviations so large that the end
point may be completely different from the initial expectations. For example, while
Columbus aimed to reach India via a Western route, he ended up discovering the
unknown and much larger continent of America.
Life as an Adventure
The appearance of diversions, in the sense of unintended phenomena that make the
agent deviate from its course, is an inevitable result of the fundamental
unpredictability of the universe. But these diversions are not random: most of them
are very meaningful to the agent, in the sense that they signal dangers or
opportunities; obstacles or resources; disturbances or affordances. The information
they provide helps the agent to correct its course of action, adding to its overall
knowledge of its surroundings. Yet, in an infinitely extended universe the unknown
will always remain larger than the known. Moreover, extending the known will at the
same time extend its frontiers with the unknown, and therefore the opportunities for
further exploration. Scientists will be the first to admit that the more they get to know
about a domain, the more they become aware of all the things they do not know yet.
A good metaphor for this driven but meandering course of action, mixing the
expected with the unexpected, is the concept of adventure. The Latin root of this
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