If you've never heard of the Dunning-Kruger effect, you are in the pre-Dunning-Kruger era. Of course you probably already knew that there was a cognitive bias in which relatively unskilled persons profess superiority, but you didn't know that it was called "the Dunning-Kruger effect". Knowing the popular name for the thing, irrespective of Stigler's law of eponymy, puts you in a new era. Regardless of how tenuous this temporal distinction may seem, it's a distinction. The tonal world is built on such tenuous distinctions.
Perhaps the first time you come across this thing (in substance but not necessarily by name) is noting a common behavior of the adolescent who brags about their sexual prowess, using language such as "I did her". You quickly learned in high school that this is a sign of dissatisfaction, lack of both skill and experience, or perhaps closeted homosexuality.
Another common example of the Dunning-Kruger effect is in the financial arena. Bling-bling-ism is used by those with financial worries and difficulties, while those who are comfortably wealthy have no incentive (and only disincentive) to show off. Getting into the magazines or publicly proclaiming wealth is more often than not a sign of psychological insecurity with regards to finances, as obligations and responsibilities are often what comes with such accumulations (see e.g. Xenophon's Οἰκονομικός for related discussion).
Today, we won't discuss these obvious examples of the Dunning-Kruger effect. Instead we are concerned with the intellectual implications for they are far-reaching. This thing is a bomb in the noosphere - or perhaps a bomb detector. As we navigate the surfaces of knowledge, we are compelled towards the peaks - the areas in which we have "learned more". The steep learning curve attracts us, and we shout "progress" and "win" as we find such areas to ascend. The Dunning-Kruger effect tells us that this is precisely when we have lost! If we imagine we have ascended it is more likely indicative of a false local maximum than the real thing.
Topologically this makes sense. The saying goes that as the sphere of knowledge increases, the surface area of the unknown increases with it. Therefore any assertion that something is "fully understood" is false. But the Dunning-Kruger effect also applies to surfaces with non-vanishing second derivatives. That is to say, you don't need to be on a peak to look down at the other climbers and say you are higher than them. While you might be in some sense higher, are you even on the right path to the next camp? Could you perhaps benefit from using some of their techniques? This is called opening the door to knowledge, which requires getting off one's high horse.
One could lump the Dunning-Kruger effect into the category of the second enemy of knowledge: clarity. But it is more far reaching than that. When we understand that assumptions of superiority are our enemy, our rational behavior as students and disciples of knowledge changes. Not only must we evaluate others differently (taking special care to question those who claim superiority) but we must also approach all topics with a base of humility.
You may have heard that the human brain is the most complex structure in the universe. That we are the pinnacle of evolution. In the context of our current discussion, making these statements nearly proves that they are false. This is like a special needs kid telling you "I'm really good at Maths" because he was able to add 2 and 2. In fact the proper assumption as a human being is that we are the dumbest structures in the universe. The lowest form of consciousness. If that is not your base assumption, before considering the context of whatever issue is at hand, you are lost to the crawling chaos of idiocy!
But wait Mr. Dwarf, humans can go to the moon! They can solve rubics cubes! Trees can't do this stuff, therefore we are smarter than trees.
First off, many people don't know the rocket equation nor how to solve a cube. But lets leave that aside. While it may be true that no tree has ever solved a cube with by manipulating it with its branches, consider for a moment that no human has ever been a net producer of atmospheric oxygen nor maintained constant communication with fungal organisms. The point is that who is better at solving problems, i.e. who is more intelligent, depends on the selection of those problems. While it might be a common viewpoint to consider the solving of a cube as evidence of intelligence, this is entirely a human context. Perhaps wasting your time on the cube inhibits your ability to maintain a deep awareness? Perhaps the energy expended was wasted? There are many ways to consider the effectiveness of consciousness. If you cannot think of many ways in which the plant or even the rock has a more advanced consciousness than the human - this is only a failure of your imagination. That we are viewing this as "human" vs. "tree" is already indicative of our mental failures. For surely we are also part of the same living body of Gaia.
And hey, why do you want to be on the moon anyway?
To find the path of knowledge requires seeing those ways in which others are better than you. Otherwise you cannot progress, and you will quickly decay.
Another example is the primitive anthropologist. The primitive anthropologist is one who studies other people and calls them "primitive". In so doing, this primitive anthropologist is blocking his own ability to learn from his studies. This is an open-shut case. The student who refuses to listen to a potential teacher, professing his superiority to the teacher on all subjects - will not learn from the teacher. When reading the works of these folks one is generally sad to see the tragedy of a lost mind, however one can learn from the anecdotes the primitive anthropologist relates - even if the primitive anthropologist cannot learn from them (as they have shut themselves in a Dunning-Kruger cul-de-sac).
So how does one navigate a post-Dunning-Kruger world? A statistical approach is of course necessary. We can look at folks who claim others are stupid and that they have the right path as most likely only useful in the sense of being able to teach us the archetype of failure. However just because somebody claims to be a know-it-all and appears long lost to the path of knowledge doesn't mean you can't learn some particular thing from them. It just makes it statistically unlikely.
Should we therefore put those who claim to be morons on pedestals as our leaders? Not necessarily. There is a difference between claiming that 2+2=5 and claiming that one has difficulties understanding the fundamental structure of arithmetic groups. In fact, if we judge a person's abilities on their verbiage, we can only have a probabilistic assessment. The best judge of skill is the skill itself. Still, we are often (perhaps always) forced to rely on probabilistic assessments to make day-to-day decisions. That Einstein claimed to be slower than most elementary school students in understanding the concepts of space and time is a reason to consider him likely wise on the topic. If he claimed most people are idiots and don't understand space and time as well as he did - well then, we would be wise to discount him as statistically unlikely to be a useful voice on the topic. Did he know this and choose his words accordingly? I think it's likely. Knowing how to brag in the post-Dunning-Kruger era is a good skill to have.
The Dunning-Kruger effect is a useful guide in navigating the world of knowledge. It's subtle, but it's something. If you are as lost as I am in this wilderness, you will appreciate being able to hold onto anything of substance. However I caution you to be wary of relying too heavily on it; like everything else, we're probably wrong about it.