Have you ever tried to prove that you are an intelligent being? This task is not as easy as it seems, and success is totally dependent on one's ability to communicate. It looks like human intelligence itself has little value unless people can exchange information with each other. What is particularly interesting is that even though intelligence is a property of an individual, the only way to validate its presence is to engage the subject in an intelligent conversation.

In a sci-fi story by Arthur Chandler called “The Cage,” a group of space travelers stranded on an uncharted planet is captured by aliens and placed in a cosmic zoo. Three people spend many days in captivity, treated well and fed. All their attempts to convince their captors that they are not animals are unsuccessful. After a while, they get used to the new environment and even manage to capture a small rodent, which they place in a handmade cage as a pet. Seeing this, their captors free them, apologize, and send them back to Earth. Why? They say, “Only intelligent creatures put other creatures in cages.”