Long before any real science was known people tried to explain how the world worked and why things are the way they are. People wanted to bring some order to a confusing and chaotic world, and have a formal way of interacting with each other. For this reason, people throughout the ages have tried to classify themselves into different groups. The most unique way by far is the concept of race. There are many reasons why the race concept is not scientifically valid, and this paper will attempt to explain why this is so.
 When people sought a way to classify the race concept, it first started as having three categories: the Mongoloids, the Caucasoids and the Negroids. Although the three categories were supposed to define three very different groups of people, there was no distinct “all or no” way to separate the categories. With the three category system, there are many people who don’t perfectly fit into any one of the three. For example, Arabs sometimes have light skin and other times medium or dark skin. They can have features from any of the three categories, like hair that is more Negriod or eyes that are more Mongoloid. So where should we put people that don’t really fit the system?
	One of the reasons the system of three categories didn’t work was that it focused on physical variation. Like with the Arab example, a lot of people have features from more then one of the categories. In fact, within a single category there is more difference then between any of the categories together. With genetic testing it is known that physical variation is 94% within a category and only 6% between any of the categories viewed together. Counting all people, we are 99.9% genetically the same.
	Another reason the race concept doesn’t work is because it assumes that the categories are pure. No one is pure in one category, because even before civilizations people from all over the world have been interbreeding. People don’t just stay in one place forever, and as people move around they mix with people from all over the world. This is probably why most people have features from more then one category, especially in places where their feature is not adaptive to where they live. 
There were very few resources for most of written history, so to try to make order in the world hierarchies were created. It was common for people in different counties to think that their county and people were the best and therefore more advanced then everyone else. When people started to sail to other places in the world, they saw that other people where doing things differently. Instead of seeing each culture as rich and equally important, they decided to think of some cultures as less then others. People chose to think that some people were better then other people. So because of this it was justified to put others into different races and put them in the lowest place in their hierarchy.
