This is humbleness, greatness and reality check all rolled into one:
What I am going to tell you about is what we teach our physics students in the third or fourth year of graduate school - and you think I'm going to explain it to you so you can understand it? No. you're not going to be able to understand it. Why, then am I going to bother you with all this? Why are you going to sit here all this time, when you won't be able to understand what I am going to say? It is my task to convince you not to turn away because you don't understand it. You see, my physics students don't understand it either. This is because I don't understand it. Nobody does.
This was Nobel Laureate Richard Feynman giving lecture to laypersons in New Zealand on Quantum Electrodynamics, his work for which he received the Nobel Prize in 1965 for physics.
By the way, replace "physics" with "economics" in the above extract and you will not be far off! Only no one as great as Richard Feynman has had the courage to admit it.