I'm going to create some definitions. And even if they're not what you hold that word or idea to mean, I ask that you set that aside for the moment and choose to let the words mean what I am defining them as.
- A model/paradigm is a set of nouns and the relationships between them.
- Truth is the congruence of an assertion against a model.
- A Paradigm shift is the acquisition of a new model which is incongruent with the current model. It does not imply loss of the current model, only acquisition of a new one (you can think in both classical mechanics and quantum mechanics, understand that 1+1=10 is true in binary and false in decimal)
Truth is relative the model used to interpret it. The frustrating implication of this is that if I want to explain why it's true, then you must have access to the model I'm using when I say it. Which, if you don't already, then you must interpret this truth from your model, where it is false. You may choose to believe this false statement, which could be sufficient to gain enough of an understanding of the new model to then evaluate truth relative to it, rather than the old model.
To travel between mutually exclusive but internally consistent models of reality requires you to make your reality internally inconsistent, figure out where it implies that true is false, and then accept both, at least for the duration of the transition. You must travel through insanity to get to enlightenment.