In his scholarly monograph “Ghosts’ Neurology and Synaptic Stuff”, the Czech philosopher Amos Komensky states that invisibility is an obvious sign of intelligence, leading him to conclude that “ghosts are more intelligent than mere mortals.” Wanting to test such claim, the Ridge College’s Institute of Intelligence Studies analyzed the behavior of two twin sisters, Gilda and Greta, the first a mortal individual, the second a ghost and javelin thrower. First of all, each was given a hat. Gilda put it on immediately. Greta was more cautious: before putting it on, she tried to change it for a portable radio and, when had it refused, she put on the hat and threw herself into the river. (According to the project manager Prof. H. Auzpel, this is to be interpreted more as a display of eccentricity than stupidity.) Afterwards, both sisters were posed the following dilemma: “A porcupine with an interest in real estate is about to drown, but is offered a chance to save himself if he marries a possum. What is the decision of the porcupine?” Gilda’s response: “He gets married,” Greta’s “He drowns but only from the waist down.” Finally, Gilda and Greta were given a twenty dollar bill each to spend on whatever they want. Gilda invested in stocks of Associated Scammers while Greta bought a portable radio and then threw it into the river. According to Prof. Heinrich Auzpel, the test results leave no room for doubt: both sisters are idiots. However, ghostly Greta is a little less idiot than her mortal twin (although Gilda has a better chance than her sister to make her way through life).