"The intelligence of the creature known as a crowd, is the square root of the number of people in it"

This quote by Terry Pratchett is an amusing take on crowd mentality. The "animal" described is the collective intelligence or lack thereof possessed by a group of people. The square root of the number of individuals in the crowd is used as a step of how intelligent the crowd is. This indicates that the bigger the crowd, the less smart it ends up being, as the square root of a bigger number is always larger. Pratchett is showing the principle of mob mindset or groupthink, where private intelligence is typically changed with conformity to the group. Ultimately, the quote works as a suggestion of the prospective risks of blindly following the crowd.