Heraclitus is making a claim that sounds like an invitation to interiority but is actually something stranger and more uncomfortable. The soul has depth not in the way a well has depth — measurable, traversable, bottomed — but in the way that depth itself has no floor to push against. You cannot travel to the end of it. The logos of the soul is not a destination.

What gets smuggled in under the word "deep," and what Snell is careful to name, is that we are not talking about a spatial dimension at all. The soul does not occupy room. This matters because most of what we do with psychological language treats the soul as if it did — as if descent were a direction you could take, as if the unconscious were a chamber with contents you could retrieve and bring back up. The spatial metaphor does real work and then stops working at precisely the moment it promises most.

Heraclitus meant this as praise: the soul's inexhaustibility is its distinction, the mark of its logos against the merely physical. But inexhaustibility is also refusal. Whatever the soul is, it will not resolve into something you have finally reached or fully known — which means the logics that promise resolution, the "if I go deep enough I will arrive" structures that drive so much psychological ambition, are already failing in the fragment itself.