Korzybski's theory of language places the source of meaning in non-verbal reactions to 'basic' undefined terms, or terms that define each other. This has two consequences for his theory of truth.

First, of course, he thinks we should determine truth using non-verbal experience.

Second, he explicitly tries to make his readers adopt 'undefined terms' and the associated reactions from math and science, due to the success of these systems. Korzybski particularly likes the words "structure," "relation," and "order" -- he calls science structural knowledge and says its math has a structure similar to the world. As near as I can tell, he means by this that if b follows a in the theory then those letters should represent some B and A which have the 'same' relation out in the world.

I don't know that 2011 science rejects his theory of language. His grand attempt to produce a system like Aristotle's does seem like a sad tale in that, while his verbal formulation of the "logic of probability" seems accurate, he couldn't apply it despite knowing more than enough math to do so.