The corporate self obtains information from the realm primus via direct interaction. But the corporate self does not interact directly with any other realm. To gain access to the valuable information in other realms other processes are needed. Those processes are the processes of excursion and reaggregation.
The best way to illustrate the processes of excursion and reaggregation is with a specific example. Take the example of a simple day-dream. First, a self constructs a mindscape which comprises the setting and the characters of the day-dream – say a daydream of a holiday. The mindscape could be a representation of a 5-star resort in the tropics – complete with palm trees and a beautiful blue lagoon for a swimming pool. The characters of the mindscape could include servants bringing you food and drink as you relax on your banana chair by the pool. Other characters of the mindscape could comprise attractive members of the opposite sex (or the same, depending on your disposition) giving you long meaningful glances across the pool. That self then splits off from your corporate self and “enters” the mindscape of your daydream (the process of excursion). The separated self now interacts with the characters of the mindscape and shares the experience immediately with the corporate self. When the day-dream ends, the separated self “leaves” the mindscape and rejoins the corporate self (the process of reaggregation).
The same general process of excursion takes place for a mathematician solving a problem, or a musician writing music. The only difference is in the form of the mindscape constructed to which the excursion takes place – a mathematical, or musical, mindscape, respectively.