Jeremy is Lobsang and Lobsang is Jeremy - they're not
[identical or even fraternal] twins but the same person so he/they are a
polarity not a paradox. By virtue of Time being their mother and Wen being an adept of existing forever through sliced time...
they are a balance of physical [and instinctive/'non-cognitive'] time (Lobsang) and conceptual/cerebral/perceived time (Jeremy) set in a polarised time niche by their parents so their
singular but separated actualities can exist in the same place (the Disc) at exactly same time.
They've been separated to make/end the paradox that the Auditors want to create to destroy time so they are the balancing factors to achieve the removal of the time anomaly (the glass clock) as though it had never happened (and yes it's fiction so this
can be done however Terry calls it because it is quantum).
It's a story about balance in effect - Order and Chaos cancel each other out and so does the realignment of Jeremy/Lobsang in A-M and then back in the History Monk's valley where the integrated Lobsang is able to re-balance the glass clock's damage and thus repair the anomaly so it never existed - I think.