Hermocrates (; ) is a hypothetical
dialogue, assumed to be the third part of
Plato's late trilogy along with
Timaeus and
Critias. Since Plato never completed the
Critias for an unknown reason, it is generally assumed that he never began writing the
Hermocrates. In any case, the persons that would have appeared are very likely be the same as in the former dialogues –
Timaeus,
Critias,
Hermocrates, and
Socrates – and the unnamed fourth companion mentioned at the beginning of the
Timaeus might have unveiled his identity. The intention of Plato to write this third dialogue becomes evident among others, from the following passage of Critias: Hermocrates had only a small share of the conversation in the previous dialogues. Since the
Critias recounted the story of the ideal state in ancient
Athens of nine thousand years ago – and why it was able to repel the invasion by the imperialist naval power
Atlantis – by referring to prehistoric accounts via
Solon and the
Egyptians, it might have been Hermocrates' task to tell how the imperialist naval power, into which Athens of Plato's lifetime had turned, had suffered a bitter defeat in the
Sicilian expedition against
Syracuse and eventually in the
Peloponnesian War against
Sparta – since he was a Syracusan
strategos during the time of the Sicilian expedition. The sequence of names of the three participants in these dialogues could also have a significance. The name of Timaeus is derived from the Greek word ,
timao meaning to pay honor to; the name of Critias is derived from the word ,
krisis meaning judgment; and the name of Hermocrates, means gifted by
Hermes, messenger of the gods.