How do you reconcile the idea that constructivism results in a subjective reality when most teachers and trainers are charged with delivery of fixed, prescribed information and ideas?

Discuss the following:

What can cause instability and dissonance in human behavior?
How do disturbances in equilibrium generate opportunities for learning?
How do you reconcile the idea that constructivism results in a subjective reality when most teachers and trainers are charged with delivery of fixed, prescribed information and ideas?
Can both approaches be accomplished in a class? Explain your reasoning.