This research intends to analyse what we call a " Stoic device of evaluation ". By "device" we make reference to a set of elements which interact between themselves in a certain way, which answer a stake and which have relations and compete with the other similar formations or not. To talk about " device of evaluation " refers to psychic processes, as well as to possible criteria which this process satisfies or has to satisfy – a certain distribution of the value – to the stake which is assigned to him and to the possible collateral effects. Value and value judgment are only the elements of a set it includes them and is characterized by the modalities of their articulation. To reconstruct a " Stoic device of evaluation " has for stake to report the way the Stoics conceive the "natural" discrimination of its environment by human being and the impact of this process. And by "natural", we shall understand "optimal " and " correct" and not actual. The device of evaluation must be indeed included as the expression of the natural, that is optimal development of the practice of evaluation such as the Stoics conceive it, what involves not to confuse natural and usual, natural and actual. We see at once that the possibility of a dysfunction is not excluded. Mutually, the " device of evaluation " emerge in the strict sense in the prescriptive reformulation of a practice of natural, that is optimal evaluation.
