The purpose of this paper is to examine some of the key parameters of the social and economic institution of slavery as it historically originated and compare these with Plato's theoretical understanding and justification of the practice particularly as this is presented in his Republic. To this end, this paper will begin, first, by looking at a definition of slavery and then go on to suggest how this is compatible with the extensive range of variation which characterizes this institution both between different cultures and over time. Secondly, the paper will turn to analyze Plato's concept of slavery focusing specifically on the importance he draws between reason and `unreason'. Finally, a brief conclusion will seek to draw from the foregoing some important implications concerning the currently received interpretation about the nature of modernity. 9 pgs. 10 f/c. 4b.