How much a person knows is not etched on the individual's face. It might be that wisdom, or intelligence, may be seen this way. But not knowledge.
Hence there are persons who pretend. There are persons who pretend to know what they are doing but they do not.
When the act falls asunder, there are pratfalls.
Here we find a certain category of things—the excitement and novelty of pratfalls, cakewalks and Keystone Kops.
It falls apart—only to create an industry.