A great teaching story !

DAVID BOHM: 
'ʹThe source of truth must be like the source of insight ‐ beyond what thought can grasp. And truth comes and touches the physical chemical state of the brain, as well as producing the words which communicate it to thought. 
Out of sleepʹ, yes. You have to be awake, alert for truth. In other words, it requires what we may call a certain ʹstate of mindʹ; really, a state of the material system as well. What generally happens when the whole system is too jangled is that it is filled with all sorts of chemical effects of this incoherent thought, which interfere with perception and put you to sleep, and so forth. You could say the brain is filled with what?
The perception of truth, which may be in a flash of insight, actually changes the system to make it more coherent. And at the same time, it produces the words, or whatever, which communicate a new foundation for thought.

The brain has to quiet down. This incoherence is the source of the electrochemical smog. Our civilization has filled the air with chemical smog, and the lungs are not in condition to breath properly sometimes. Similarly, the brain is not in a condition to respond to truth.

In this smog, it doesn't; or it responds in a confused way. And therefore itʹs not truth.'


https://www.youtube.com/watch?v=W6wpEpfx5dQ