I found Henry Gates Jr. to be spot on when it comes to the idea that physical attributes are not the only way people can be classified into a race. Like Burke's terminatstic screens Gates believes that can be created within a text and are associated with people by people. Race is a very ambiguous terministic screen simply because people do not have the same views of others. Race is a social construct since a person can be considered part of certain group by their location that they were born or their religion. I myself have been told hundreds of time that I am not white because I am Jewish. Being Jewish is not a race but to many people it is and with that reinforcement placed on me many times over I have caught myself identifying myself as Jewish when race is brought up in a conversation.
The classification of race is also based on time period. 50 to 60 years ago race was a completely different subject that is almost unrecognizable in today's standards of living. The ideas that African Americans could not read or in their minds should not be able to read are extremely offensive and shows the power that race had on people's ways of life. Today race in someways is important to one's identity since most people associate themselves with their modern day race, but modern day race was not even an after thought to people of the past.