First, it is stressed that a rhetorical dimension is forcibly present in the performance of dialog, if dialog is understood both as an invitation and as a reciprocal openness for a constructive process; it can be demonstrated if one looks at some proposals of dialog (Buber 1922, and more recently Isaacs 1999). Usually the refusal to consider that there is a rhetorical aspect aims to keep a specific communication process protected against undue manipulation or abuse; but a false assumption is then made. To guard against such a slope, many authors have pleaded for a rhetorical ethic or an ethic of the rhetoric (Johannesen 19964). It has to be discussed whether some distinction should be made between valid and non valid forms of rhetoric, and one has to review the conditions of an ethical rhetoric and ask how and if they could be meaningfully used as criteria of exclusion (of the nonrhetorical as non-ethical and vice-versa).