The NHS translation of Thomas 67:
Jesus said, “One who knows everything but lacks in oneself lacks everything.”
DeConick’s translation:
Jesus said, ‘Whoever knows everything, but needs (to know) himself, is in need of everything.
In the Book of Thomas which is also included in Nag Hammadi codex II, Jesus says to his ‘twin’ Thomas that
those who have not known themselves have known nothing, but those who have known themselves already have acquired knowledge about the depth of the universe.
— Meyer (2005, 210)
Strangely enough, this fits with the logical sense of depth (intension), which is intrinsic or internal to a term or symbol while its breadth (extension) is extrinsic or external. Given that we ourselves are symbols, as Peirce says, ‘everything which is present to us is a phenomenal manifestation of ourselves’ (EP1:38). Its presence to us necessarily involves its otherness, its Secondness to us, its externality, while the form this manifestation takes for us arises from the depth of internality: its Firstness is the form of what matters to the bodymind. The Thirdness of the phenomenon is the sign’s act of meaning, the semiosis.