1. Realms

Animals divide their worlds into territories... This part is mine, and I will defend it. That part is hers, and if I cross the boundary, there will be a fight. Any creature that cannot instinctively ‘see’ these boundaries is at a serious evolutionary disadvantage. And so, just as one might expect Minskyan mind agents to have developed to recognise food or shelter, another, we can postulate, is responsible for dividing up any landscape we are confronted with. It has to divide it into adjoining areas according to the rules of evolutionary advantage.

In order to successfully negotiate one’s way through a landscape, it is no good heading off towards an area bounded by a line of steep cliffs twenty feet high, or bounded by a river, or by a dense stand of vegetation. The eye is naturally directed along such boundaries until it finds a point of transit - a portal - between them: a gap, shallows with stepping stones, a bridge, a negotiable slope, or outcrop of rocks which look climbable.

The line of the boundary acts as one guide, catching and directing the eye of the viewer, and the point of contact between the territories or realms too has special emotional significance. We are pre-programmed to be aroused by such points. The agent looks for boundaries and portals, and recreates the landscape in our brains using these as the basic framework on which to hang other features. A third key feature would also be line-like – a pathway through our landscape, perhaps trodden down by thousands of previous transits by animal herds, or just as a natural feature.