Zach is the Jesus to Ethan's Doubting Thomas in this fascinating debate on the Truth, and how we can possibly know Reality when we see it. Zach believes that Objective Reality is Real, and that it's accessible to those who haves been Saved/Reborn/What-have-you. Thus he has access to Absolute Truth - sometimes. It's therefore very awkward to be debating with someone without such access - and yet it is precisely Ethan's doubting quality that grounds this conversation.
It could only be in the presence of a hardcore Post-Modernist like Ethan that the idea of an Objective Reality has to be so firmly asserted. Yet Zach can only concede this point by dividing people into the Chosen and the Not-So-Chosen, with regards to access to this Objective Reality.
The Truth is Out There. Even Descartes would approve of the closing remarks, in which the only thing Ethan and Zach are sure of is their continued interest in the Trio!