A scientific theory classifies phenomena based on a universal set of structural relationships. Experiments and theories which deserve the name scientific thus share a coherent set of properties. First, they are systematic, meaning that phenomena as presented possess certain structural or virtual unities despite actual or potential diversities. A fully systematic theory is also complete in that nothing is arbitrarily left out of the universe of discourse.
Events, spaces and processes are presented as approximating a mode of relation which is in every case either symmetrical or complementary, and possibly even transitive (symmetrical and complementary.) Consider the relation between two inter-connected processes A and B. A symmetric relationship could be as follows: A exhibits behavior x when B exhibits behavior x, and A exhibits behavior y when B exhibits behavior y. Complementary relations, on the other hand, could be (for example): A exhibits x when B exhibits y, and A exhibits y when B exhibits x. Complementary relations are characterized by a disjoint or heterogeneous symmetry which distinguishes them from the smooth or homogenous symmetries of the first type of relation.