Socrates now changes the direction of the inquiry, asking Euthyphro whether holy deeds are approved by the gods because they are holy or whether they are holy because they are approved by the gods. To illustrate his point, Socrates draws the distinction between being x and getting x. Something carried is being carried because it gets carried: it does not get carried because it is being carried. "Being carried" is the state of the object that is being carried, the state of the object that is acted upon. "Getting carried" is the action of which that the object is on the receiving end. In saying that something is being carried because it gets carried, Socrates is arguing that an object can only be in the state of being carried if someone decides to carry it--that is, if it gets carried. A thing becomes changed because something else changes it: it does not get changed by something else because it is already a changed thing.
Socrates then draws a similar distinction between being approved and getting approved. A thing is being approved because it gets approved, and not the other way around. We cannot say that it gets approved--that someone decides to approve of it--because it is already being approved by that someone. According to Euthyphro's definition, something gets approved by the gods because it is holy and not the other way around: it is not holy because it gets approved by the gods. And because it gets approved it is being approved, and thus is something that is approved by the gods.
It follows from this argument however, that what is holy is something different from what is approved of by the gods. Something holy gets approved because it is holy, and something that is being approved by the gods is being approved of because it gets approved. If what is being approved of by the gods were the same thing as what is holy, and if what is holy gets approved because it is holy, then what is being approved of by the gods would get approved because it is being approved of, when in fact the opposite is true. Alternatively, if we accept that what is being approved of is being approved of because it gets approved, then the holy, too, would have to be holy because it gets approved, and not the other way around.
Though the argument Socrates' presents here sounds quite complicated and is very difficult to state clearly, it is actually relatively simple. Under discussion are three things we might say about a certain deed, and three claims Euthyphro is committed to. The three things we might say about a certain deed are:
(A) It is holy
(B) It gets approved of by the gods
Socrates is treating Euthyphro as the teacher when in fact Socrates is teaching Euthyphro
Plato suggesting that there is no such thing as a definition of holiness, that there is no one feature that all holy deeds have in common?
What Plato/Socrates is challenging is Euthyphro's/everyone's knowledge or assumed knowledge of anything, not the can we know anything idea, but have we challenged our beliefs? Are we sure that the conclusion we hold is conclusion enough? Peirce and James pick this up again a few years later.