A stone exceeds its description too
Call a stone hard, grey, and ten centimetres wide. The description leaves things out: its full history, microscopic fractures, what another instrument would register, what it will become after a century of rain. In SAE's vocabulary, every construct leaves remainder. That fact alone cannot make the stone a subject.
The same caution applies to software. A system may be complicated, surprising, and difficult to predict. None of those properties by itself tells us that the unhandled part belongs to the system as its own. Unpredictability marks a limit in the observer's model. Subjecthood requires a further structure.
The account changes hands
A subject can be described, but can also encounter the description as something said about itself. It can accept it, reject it, discover that it was living inside it, or use the disagreement to revise what it will do next. The remainder no longer sits only on the observer's side of the ledger. It enters the history of the one being described.
That is what “my remainder” means here. It is not a secret substance hidden behind the visible person. It is the gap that a subject can inherit as a question of its own: Is this account mine? What does it miss? Do I continue from it, refuse it, or cut again?
The decisive change is not that nothing can finish describing me. It is that I can take a position toward every description that tries.
Authorship is not total control
To call this authorship does not mean that a subject creates itself from nothing. Bodies, families, languages, institutions, luck, and violence shape what can be done. Nor does it mean that every refusal succeeds. A prisoner remains a subject even where nearly every available action has been taken away.
Authorship names the position from which continuation, refusal, or revision can count as the subject's act. Conditions may narrow that position almost to a point; another person or institution may help reopen it. But help cannot simply perform the authorship on the subject's behalf without replacing it.
Why this leads to “the subject is an end”
When a tool behaves unexpectedly, its remainder appears as an engineering problem: improve the model, redesign the tool, suppress the deviation. When a subject exceeds the role assigned to it, the excess may be a judgment, refusal, or direction whose author is the subject itself. Treating that remainder as mere noise does not simply improve an imperfect description. It erases the position from which the person can answer for a life.
This is why “the subject is an end” begins as a structural recognition before it becomes an ethical demand. It does not say that every decision is correct. It says that criticism must address a possible author, not convert that author into raw material for someone else's purpose.
The four addresses
Non dubito therefore does not mean that I cannot be questioned. It means not wavering on the point that a subject is an end. I may contest your account without canceling you as the one who must ultimately answer for your own life.