The paper offers an interpretation of a disputed portion of Plato’s Theaetetus that is often called the Secret Doctrine. It is presented as a process ontology that takes two types of processes, swift and slow motions, as fundamental building blocks for ordinary material objects. Slow motions are powers which, when realized, generate swift motions, which, in turn, are subjectively bundled to compose sensible objects and perceivers. Although the reading of the Secret Doctrine offered here—a new version of the “Causal Theory (...) interpretation”—is not without problems, these problems are acknowledged in Plato’s text, confirming that this interpretation is correct. (shrink)