Modality Variables
Similar to Deictic Center.
E.g.: VISION, AUDITION, WHEELS, ARMS
*VISION = Holds(Lookat(Cassie, Stu), t3)
- if vision currently occupied by looking at Stu
- t3 denotes the time during which Cassie will be looking at Stu
- *NOW is during t3
Set at PML when bodily state starts/ceases.
One state may occupy multiple modalities.