Hawking's Communication Method

Okay, so this joke is funny because it makes a comparison between a boxer, who uses his fists to communicate, and Stephen Hawking, who, because of his condition, used a wheelchair and a speech synthesizer to communicate. See? Boxing with fists, Hawking "boxing" with wheelchair. I know your brain is small, but that's how it works. Remember that Stephen Hawking was a genius and you are not.