Two conceptions of decision aiding

After a brief presentation of three pillars on which decision aiding is founded, the paper describes two clearly different conceptions on which decision aiding can be carried out. The first one (Section 2) is primarily positivist, and the second one (Section 3) is primarily constructivist. These two conceptions are not incompatible and do not exhaustively cover all the conceptions conceived and used. Section 4 illustrates the differences between these two conceptions with regard to a specific point. Section 5 schematises on three levels what differentiates these two conceptions.