The expertize of a concert pianist or tennis player is very clearly demonstrated to the public at each performance, and the public can on good grounds express appreciation by applause.

But the general public cannot directly judge the expertize of a scientist or a priest, because the nature and depth of the expertize is beyond comprehension for non-specialists. The Nobel Prize ceremony illustrates the difficiulty: Scientific priests of lower rank convey a message to the Royal family and the general public in presentation speeches, that they truely understand the remarkable scientific achievements of the Laurates, while it is understood that nobody outside the inner circle can understand. It is a spectacle which works under the assumption that some few understand something which is hidden to the many.

A theoretical a subject without obvious practical results is difficult to judge, since understanding of the theory is required, which however is restricted to the inner circle.

But pretending to understand can be a substitute for real understanding. From outside, it can be difficult to judge if someone really understands a theory without practical conseuqences, or just pretends to understand. It is like judging if a priest claiming to believe, really believes or just pretends to believe.

The theoretical subjects of theoretical physics and pure mathematics are particularly prone to pretending. Theoretical physicists (have to) pretend to understand

- relativity theory: fabric of curved spacetime
- quantum mechanics: wave-particle duality, collapse of wave-function
- cosmology: Big Bang,

pure mathematicians (have to) pretend to understand

and theoretical fluid dynamicists pretend to understand

while understanding of these subjects is not possible for the general public.

The highest priests of theoretical physics can admit that they don't understand, which is to be taken as a sign of an even deeper understanding. Compare with Science vs Religion and Presentation Speech Nobel Prize in Physics 2004: Asymptotic Freedom:

- Nature has chosen the only theory we have found to be possible.

Like Newton, modern physicists dictate Nature, not the other way around.

How do you show that you understand something? By nodding your head! If a group of scientists collectively nod their heads, a scientific truth has been established.

The education in mathematics and theoretical physics/mechanics aims at implanting a strict codex of basic beliefs, which is also the goal of religious schools, and there is little room for critical independent thinking. While practice can harbor multivalued truth, it seems that theoretical science and much of religion only can accept the one truth preached by the high priests. If you cannot make yourself pretend to understand, then you are in trouble, and maybe you choose to study something else than mathematics and physics...or religion...