representational inquiry regarding meaning » intelligibility
Each node in the O-phase combines a mode of experiencing/attending with a relationship between experiencer and experienced. The modes of experiencing/attending disclose different relationships between experiencer and experienced. The relationships plus the mode of attending constitute different modes of intelligibility—namely, subjectivity, activity, and objectivity. Together, the discursive activity of running between subjective, active, and objective attending opens within reality a domain of intelligibility, disclosing reality as meaningful/experiential. This intelligible realm is represented by the egg symbol/diagram, and the vesica formed at the intersection of overlapping spheres represents how this disclosure relies on the overlapping of different modes of intelligibility. The modes of intelligibility aren't mutually exclusive but are always mixed together even as they tend toward different types of experience and knowledge.
As the Project's tree-structure (diagramming its logic) folds and unfolds, it scribes arcs which, when looked at from the side, resemble a circle; that's the main reason the letter O is used to represent this phase of the Project.
The original meaning of the letter O is eye (as in oculus [L] or ops/optikos [G]). This suggests a point-of-view which is limited by a field of view. The letter O is thus applied to the questions concerning truth and knowledge (construed broadly), as all knowledge occurs from a point-of-view within a domain of knowability (field-of-view). Going along with this, the graphic representation of the letter O at once suggests the shape of an eye and a bounded world (domain of intelligibility).
Relatedly, O's shape may signify ovum (egg). It is within this egg that the seed of potential (I) may germinate and grow, becoming actual (A), to ultimately bear fruit (L).