3.

There is no nature, Nebridius--and, indeed, there is no substance--which does not contain in itself and exhibit these three things: first, that it is; next, that it is this or that; and third, that as far as possible it remains as it is. The first of these three presents the original cause of nature from which all things exist; the second presents the form ¹ according to which all things are fashioned and formed in a particular way; the third presents a certain permanence, so to speak, in which all things are. Now, if it be possible that a thing can be, and yet not be this or that, and not remain in its own generic form; or that a thing can be this or that, and yet not be, and not remain in its own generic form, so far as it is possible for it to do so; or that a thing can remain in its own generic form according to the force belonging to it, and yet not be, and not be this or that,--then it is also possible that in that Trinity one Person can do something in which the others have no part. But if you see that whatever is must forthwith be this or that, and must remain so far as possible in its own generic form, you see also that these Three do nothing in which all have not a part. I see that as yet I have only treated a portion of this question, which makes its solution difficult. But I wished to open up briefly to you--if, indeed, I have succeeded in this--how great in the system of Catholic truth is the doctrine of the inseparability of the Persons of the Trinity, and how difficult to be understood.