The Commens Dictionary

Quote from ‘Letters to Mario Calderoni’

I find that there are in the phaneron,
[—]
3^rd, elements each of which is as it is to a second and for a third, that is, its very being, as phaneron, consists in its bringing that second and that third into relationship. Such an element I call a Tertian element.

You naturally expect Quartan elements, [and] so forth. But I not merely opine, but can strictly demonstrate that every quartan part of a phaneron is reducible to a combination of Tertian elements. You might thoughtlessly ask why then a Tertian part cannot be reduced to a combination of a Secundan elements. But a moment’s reflection will show that this is a senseless and purely verbal suggestion, inasmuch as combination is already a Tertian idea.