Anyone who has ever owned a cat knows that cats are pretty smart creatures, often smarter than the average Congressman. However, many people still question the intelligence level of cats mostly because those people have intelligence levels that are far below that of the average cat, so it’s no wonder they can’t recognize the superior intellect of a feline when they see it.
Wikipedia has a fairly typical article regarding the intelligence of cats. For example, there’s a statement that questions whether cats can dream. There are other statements mentioning how cats may seem to be able to learn new behaviors. Such statements of the obvious make you wonder if cats might not be more intelligent than the average person on the planet, so that’s why humans consistently doubt the intelligence level of the animals around them.