Even if we did not know that our mind is eternal, we should still consider as of primary importance piety and religion, and generally all things which, in Part IV., we showed to be attributable to courage and high--mindedness.
Proof .-- The first and only foundation of virtue, or the rule of right living is (IV.xxii.Coroll.and xxiv.) seeking one's own true interest.

Now, while we determined what reason prescribes as useful, we took no account of the mind's eternity, which has only become known to us in this Fifth Part.

Although we were ignorant at that time that the mind is eternal, we nevertheless stated that the qualities attributable to courage and high--mindedness are of primary importance.

Therefore, even if we were still ignorant of this doctrine, we should yet put the aforesaid precepts of reason in the first place.

Q.E.D.
Note .-- The general belief of the multitude seems to be different.