ABSTRACT
Environmental Impact Assessment is usually applied to specific development proposals. This incremental approach seems to be realistic; nevertheless, it will meet some difficulties in facing cumulative effects and irreversibility problems. The paper discusses if and on what conditions a plan can be assessed by a technique like EIA. After defining these conditions, the paper tries to verify their appropriateness in practice, by discussing the EIA of the land-use plan of Aosta, Italy. The sketch of the more relevant issues of the impact study illustrates the central hypotheses proposed by the paper: (i) assessment methodologies, as decision-aid tools, are problem-setting rather than problem-solving techniques; (ii) their form is rather argumentative than demonstrative: being based on disputable judgments, searching a negotiated consensus between involved actors, they seem to belong to the field of rhetorics.
