A goal is a cognitive attitude of some agent concerning a certain occurrent (state of affairs, situation, process) that could become true if some action is initiated. Very complex issues are involved here. This definition is only a rough conceptualization. An entire theory should be built around such issues. Consider also the link with the '_intentional' granularity.
(<=> (Goal ?A ?B) (And (Representation-Relation ?A ?B) (Exists (?C) (And (Believes ?A ?C) (Interpretant-Of ?C ?B))) (*Agent ?A) (Temporalized-Entity ?B)))