The idea that a diverse population needs a diverse environment to succeed seems easy enough to grasp. Certainly, it is easier to comprehend than a one-size-fits-all design philosophy. Why then, in the name of universal design and equality, do architects continue to design uniform one-size-fits-all environments? Answering that is not so simple. Some may suggest that construction methods, costs, and site restrictions make diverse environments economically and physically infeasible. Others may fault the lack of courses architects take in human biology and psychology. This might make it impossible for them to understand the diverse range of people their buildings affect. Even more may fault the ever increasingly abstract design process. This may hinder architects’ ability to identify with real future occupants. All of these conceivably play a role, but the most likely culprit is Plato’s philosophy of essentialism for the same reason biologist Ernst Mayr felt it caused evolution’s insufferably late discovery; essentialism has and continues to fundamentally shape how we see and deal with diversity.