The Trainyard Metaphor

In an immense trainyard, tracks stretch in all directions, yet converge toward a single orientation. They form sets arranged in pairs, with a swampy ditch running between each pair. Crossing between these sets is possible, but doing so in the space between boxcars is awkward—far better to navigate by staying inside them.

Within this world, there are two employees working around the clock:

1. The Operator (Wizard): Stationed in the control room, he oversees the entire yard, aware of every locomotive (action or goal). This operator possesses a secret: the ability to teleport, allowing him to discreetly polish and prepare locks on certain boxcars without the other employee’s knowledge.

2. The Janitor (Agent): On the ground floor, the janitor cares for the trains and tracks. When the lunch bell (goal activation) rings, the janitor’s primary task is to reach the control room as efficiently as possible. To do so, he hops from one boxcar (action) to another, following whatever sequence leads him to his meal. The janitor adores keys and locks, especially those with aesthetic appeal, and is drawn to them when deciding which path to take.

Sometimes, the janitor switches roles to that of a security guard, locking certain doors behind him. This prevents looping or revisiting the same action multiple times, ensuring forward progress. Inside each boxcar sits a table holding keys. Once the janitor enters, he waits for a signal indicating it’s safe to act and move on. The keys he finds may be kept, used once, or have limited uses—details that shape his future decisions.

The janitor surveys the line of boxcars and picks one whose locks and keys he finds most appealing. If none looks good, he simply waits, patient, until conditions improve—much like weather changes that could shift objects (world states) into positions that can serve as keys. Sometimes, waiting is better than forcing a bad move and causing a disaster.

This trainyard metaphor reflects a biological analogy:

• Keys and Locks resemble neurotransmitters and receptors.
• Each boxcar (action) is like a neuron firing after being unlocked by the right neurotransmitter (key).
• Goals are like signals triggering specific sequences, leading to states the system desires to achieve.

If a plan fails—perhaps a neurotransmitter (key) never finds its receptor (lock), or the janitor can’t progress—there’s no total collapse. The agent (janitor) adjusts, picking another boxcar or path. Similar to how neurons activate alternate pathways, the system keeps moving.

In KLAP, influence matters. The janitor’s preference for certain locks and keys leads to focusing on key junctions rather than exhaustively planning every possibility. This saves computational resources and time.

Over time, trains (actions) can roll in or out of the yard. This modular nature means actions can be introduced, adjusted, or removed without disturbing the entire system. The trainyard’s shifting landscape symbolizes KLAP’s adaptability, its ability to evolve alongside changing requirements or conditions.

Finally, consider how goals differ from standard actions: they can issue an activation key (like a stationmaster’s bell) that triggers a chain of actions culminating in the goal’s achievement. This chain is known as the Process. The Process represents a strategic sequence of abilities leading to a desired outcome—a state or behavior beneficial to the system. By encompassing more than just simple goal attainment, the Process supports nuanced, dynamic interactions with the environment, further enhancing the system’s flexibility and efficiency. a boxcar, rather than causing a disaster by forcing it open prematurely.

This train yard metaphor, in essence, models the synaptic gap and the cascade of chemical reactions within the human brain. The keys and locks symbolize neurotransmitters and their receptors, respectively. Each action is similar to a neuron firing and, upon successful completion, it releases the neurotransmitter (the key) which can unlock the next neuron (the boxcar), facilitating a subsequent reaction or action.

If the plan does not work as anticipated - for instance, a neurotransmitter doesn’t find its receptor, or the janitor ends up stranded between boxcars - the system doesn’t grind to a halt. Instead, the agent (the janitor) looks for the next available course of action - the next boxcar he can unlock, or in biological terms, another neuronal pathway gets activated. This fallback mechanism ensures that even if certain plans fail, the agent can adapt and keep moving forward.

KLAP operates on the principle of influence, which in this metaphor, is manifested by the janitor’s preference for aesthetically pleasing locks and keys. In terms of planning, this influence-driven operation results in the creation of plans only for key junctions or decision points in an action sequence, instead of generating exhaustive plans for every possible course of action. This approach is efficient, saving both computational resources and time.

Moreover, the metaphor underscores the dynamic nature of the KLAP system. Just like trains (actions) can roll in and out of the yard at any time, actions in KLAP can be introduced, modified, or discarded as required. This reflects the system’s modularity, where components (actions) can be individually manipulated without affecting the entire system’s operation. The train yard’s ever-changing landscape is a visual representation of the planner’s customizability in the KLAP framework, demonstrating its capability to adapt to new requirements or changing conditions.

Lastly, let’s delve into the concept of goals in KLAP. They bear a striking resemblance to actions, with one notable exception. Goals can issue their activation key, much like a stationmaster ringing the lunch bell. This activation key can trigger a series of actions that eventually lead to a goal. This triggered goal can then set off another series of actions, creating a chain reaction that eventually culminates in the attainment of the ultimate goal.

In KLAP parlance, this chain of reactions is referred to as the Process. The Process is a strategic sequence of abilities that lead to the desired behavior. It’s important to note here that the desired behavior is not just goal attainment in the traditional sense. In KLAP, it also encapsulates any beneficial or advantageous state or condition the system aims to achieve or maintain. This comprehensive approach allows for a more nuanced and dynamic interaction with the environment, further enhancing the system’s adaptability and effectiveness.