What ought to be done · Lexicon

From the book

Charmides

Plato · Diotimos Editions · 2026

Orientation

At a Glance

The wordTa deonta is the neuter plural participle of the impersonal verb dei, “it is necessary” or “one ought.”
In the CharmidesIn the doctor example Socrates asks whether someone who benefits himself and the patient does ta deonta, and whether doing these things is temperate (164a–b2).
In this edition“Does what he ought” interprets τὰ δέοντα idiomatically.
A place to readThe needed treatment is expressed through conditional verbal adjectives of obligation.

Meaning

Ta deonta is the neuter plural participle of the impersonal verb dei, “it is necessary” or “one ought.” It names what is required or what ought to be done. The dialogue also uses verbal adjectives such as doteon, “to be given,” and epāisteon, “a charm must be sung,” to express the required next step. Such constructions range from practical necessity to normative requirement; they do not automatically establish a theory of duty independent of benefit.

Use in the book

In the doctor example Socrates asks whether someone who benefits himself and the patient does ta deonta, and whether doing these things is temperate (164a–b2). Critias agrees. The phrase links beneficial action with proper action under his current definition. It does not explain how to determine what is required when benefit is uncertain. That uncertainty immediately drives the question whether the practitioner knows how he has acted.

The medical frame has already presented conditional prescriptions: if Charmides has temperance, the remedy should be administered; if he lacks it, charming must come first (158b–c). The practical conclusion depends on a diagnosis which the inquiry has not secured. Likewise the impersonal requirement to examine what appears, if one cares for oneself, binds intellectual investigation to responsible action (173a). “Ought” here can require inquiry rather than a confident command.

Places to read

158b–cThe needed treatment is expressed through conditional verbal adjectives of obligation
164a–b2Beneficial treatment is accepted as doing what one ought
173aCare for oneself requires examining the puzzling appearance

Translation in this edition

“Does what he ought” interprets τὰ δέοντα idiomatically. It should not be confused with the separate “one's own” formula: the doctor’s action becomes proper through the conceded benefit, not simply through ownership of its materials or patient.

δέον

Attested: δέοντα (deonta). What ought to be done or what is required; the beneficial doctor is said to do these things, connecting useful treatment with Critias’ account of temperate action. References: 164b. Lexical identification: lemma: δέω (impersonal δεῖ); τὰ δέοντα is the substantivized participle. See What ought to be done.

δοτέος

Attested: δοτέον (doteon). To be given, or must be administered; the remedy for Charmides’ head could be given immediately if he already possessed sufficient temperance. References: 158b. Lexical identification: lemma: δοτέος (verbal adjective of δίδωμι). See What ought to be done.

χρή (chrē)

It is necessary or one ought; an impersonal expression used to press how Hesiod’s claim should be understood. References: 163b. Lemma: χρή. See What ought to be done.