Moral Letters to Lucilius Section 4

Singula animalia singulas habere debent substantias; ista omnia unum animum habent; itaque singula esse possunt, multa esse non possunt. Ego et animal sum et homo, non tamen duos esse nos dices. Quare? Quia separati debent esse. Ita dico: alter ab altero debet esse diductus, ut duo sint. Quicquid in uno multiplex est, sub unam naturam cadit; itaque unum est.

Chaque animal doit avoir une substance à part ; tous ont une âme qui est la même : ils peuvent donc exister comme isolés, non comme plusieurs à la fois. Je suis en même temps animal et homme, sans qu’on puisse dire que je sois deux. Pourquoi ? C’est qu’il devrait pour cela y avoir séparation : c’est que l’un doit être distinct de l’autre pour qu’ils fassent deux. Tout ce qui en un seul est multiple tombe sous une seule nature ; il est un.

Each living thing must have a separate substance; but since all the things mentioned above have a single soul, consequently they can be separate living things but without plurality. I myself am a living thing, and a man; but you cannot say that there are two of me for that reason. And why? Because, if that were so, they would have to be two separate existences. This is what I mean: one would have to be sundered from the other so as to produce two. But whenever you have that which is manifold in one whole, it falls into the category of a single nature, and is therefore single.