Relations and notional acts; five notions of the persons
If the Father alone begets, it is proper to Him to beget; if the Holy Spirit alone proceeds and is spirated, it is proper to Him to proceed and be spirated. And there is a similar relation in mode between Father and Son.
But a notion is nothing other than a property or notional act, which by synecdoche of the genus denotes relation. Hence in the schools there are in all five notions of the divine persons, concerning which besides the ancient scholastics and most learned men Jerome Zanchi and Franciscus Junius, see the Leiden theologians Synopsis of purer theology, disputation 7 theses 21-24.
The Trinity of persons can in some way be illustrated by likenesses from the book of nature: but it ought to be demonstrated from the book of Scripture alone. For from finite things to Gods infinite essence the consequence is too weak, and this secret is higher than natures light.
Latin
Si solus Pater gignit, proprium est ipsi generare; si solus Spiritus sanctus procedit ac spiratur, proprium est ipsi procedere ac spirari. Ac similis in modo est inter Patrem et Filium relatio. Est autem notio nihil aliud quam proprietas seu actus notionalis, qui per synecdochen generis relationem denotat. Unde in scholis quinque in universum sunt divinarum personarum notiones, de quibus praeter scholasticos priscos et doctissimos viros Hier. Zanchium et Fr. Junium, videas theologorum Leidensium synopsin purioris theologiae, disp. VII.thes.21-24. Trinitas personarum illustrari quodammodo potest similitudinibus e libro naturae: demonstrari autem debet e solo libro Scripturae. Nam a rebus finitis ad infinitam Dei essentiam infirma nimis consequentia est, et hoc arcanum lumine naturae altius est.