no distinction between peripheral systems - activity producing system as a layer - activity as a pattern of the interactions with the world - activities might aswell be called skills

Herbert has 14 relatively independent and closely knit subsystems, each encompassing both structures of the robot and structures outside of it. Each of subsystems is somewhat mental, somewhat bodilyy and somewhat worldly. This is, according to Simon's principles of intensity of interaction, the primary division is not into mind, body, world, but rather into "layers" that cut accross these

outer surface of robot is not a primary interface