MARCUS: Nor am I asham’d, as some others are, to confess I do not know, what I do not.

[Nec me pudet ut istos fateri nescire quod nesciam.]

Marcus Tullius Cicero (106–43 BC) Roman orator, statesman, philosopher

Tusculan Disputations [Tusculanae Disputationes], Book 1, ch. 25 (1.25) / sec. 60 (1.60) (45 BC) [tr. Wase (1643)]
    (Source)

Discussing his uncertainty of what the immortal soul is made of, versus others that pretend at knowing the answer.

(Source (Latin)). Other translations:

Nor am I, like those, ashamed to own where I am ignorant, that I am so.
[tr. Main (1824)]

Nor am I ashamed, as those are, to confess my ignorance of what I do not know.
[tr. Otis (1839)]

Nor am I, as those men are, ashamed in cases where I am ignorant, to own that I am so.
[tr. Yonge (1853)]

And I am not ashamed, like those who deny that there is a soul, to confess my ignorance of what I do not know.
[tr. Peabody (1886)]

Nor am I ashamed -- as some whom you wot of -- to confess that I do not know what I do not know.
[tr. Black (1889)]

I am not, like some men, ashamed to confess my ignorance when I do not know.
[ed. Harbottle (1897)]

Nor am I ashamed, as they are, to admit that I do not know what I do not know.
[tr. Douglas (1985)]

And I'm not embarrassed (unlike others) to admit that I don't know.
[tr. Habinek (1996)]

And unlike those others, I am not ashamed to admit to my ignorance where I am ignorant.
[tr. Davie (2017)]