Relations are truly, though not very lucidly, said to be either relations of reason or relations in re. The latter expression the more obtrusively fails to hit its nail squarely on the head. It would be better to say that relations are either dicible or surd. For the only kind of relation which could be veritably described to a person who had no experience of it is a relation of reason. A relation of reason is not purely dyadic: it is a relation through a sign: that is why it is dicible. Consequently the relation involved in duality is not dicible, but surd; and duality must contain as an ingredient of it a surd disquiparance.
…a conceptual duality is no true duality, inasmuch as it involves a reference to a third correlate, namely, to the conception. Therefore, in the analysis just given, all reference to conceptual relations must be struck out. True duality is a real or surd relation.