They"re not considering whether plessy did/didn"t violate the law - he is guilty. Not considering, for the purpose of the law, if he is black (he"s 1/8 black, 7/8 white) What"s being disputed: does the separate car act violate the 14th amendment? (is it unconstitutional) The argument: there is a social difference that laws cannot, and should not, try to alter. As long as the difference between whites and blacks is recognized, there will always be a social difference between the two - the law can recognized this difference without harming either group. Social vs. legal equality - social differences don"t necessary create a legal inequality. The court"s ruling: the separation of races doesn"t abridge the privileges or immunities of the colored man - doesn"t violate the 14th amendment. This law is created for the notion of the public good, not for the annoyance or oppression of a particular class.