The author compares two theoretical models which develop constructs of an ideal audience. Chaim Perelman's universal audience serves a methodological function within the New Rhetoric which provides for the examination of philosophical arguments on values. Implicit within the work of Isocrates is a competing image which asserts that the ideal audience is empowered by the conditions of argument to engage the advocate in discursive praxis to construct and embody a consensus on contingency-driven value debates. The author concludes that the concept of an ideal audience will be most valuable where interest in adherence to theses is less central than attendance to relationships born in and borne by discourse. Such a view has purchase within a constitutive view of rhetorical relations which asserts that the most useful role for argument is as an invitation to engagement. The situation of argumentation within a deontological ethics requires the partnership and participation of individuals in a mutually constructed discursive praxis.