The one comment I would make against this is that you've got it
backward. Wallace gives a good explanation of how this all works in his
grammar, but basically when you have a subject and a predicate
nominative to identify, the definite one will be the subject--in this
case, "everything which is being made manifest is light."
>
> However, Irenaeus seems to translate the phrase as if PHANEROUMENON is a
> deponent - "making manifest", so that he (quoting Ptolemy) ends up with the
> phrase "all that makes manifest is light".
Now, I guess it depends on how you take "deponent." You might want to
check out a thread that came up not too long ago on this list, in which
Carl Conrad explained his approach to middle/passives, suggesting that
the middle idea is basic, and the passive builds off of that. A
deponent then is not a middle/passive functioning as an active per se,
but it would simply be one of the potential uses for the middle voice.
(Carl, am I getting this right?) I would say "all that makes manifest"
fails to capture this middle idea (since it assumes something else is
the object of manifestation), so we may almost be forced into a more
reflexive middle idea: "all that manifests itself." Practically
speaking, I don't know that we end up too far from a passive idea, once
we've gone that route.
Trevor