ABSTRACT

A social system is said to be subject to determinism if knowing its state in t, we can predict its state in subsequent ‘moments’ t+1,…,t+k, etc. But two types of situation must be immediately distinguished. It is possible that no elements enabling the observer to predict the state of a system in t+1,…, t+k, etc, are available to him, although the future state of the system is contained in its present state. It can be said, in this case, that the system is objectively determined, but seems subjectively to be undetermined. Although the trajectory of a falling leaf is entirely determined, it is difficult to predict where it will fall, as generally the characteristics of the forces determining its trajectory are not known. One knows only that it is very likely, or at least that there is some probability (the value of which can eventually be determined) that it will fall within a given circle. When a system is such that, even while assuming an omniscient observer, the state of the system in t+1, …, t+k, etc., can only be known starting from the knowledge of its state in t, the system will be said to be either objectively undetermined, or abstracted from the ‘general law’ of determinism. The question whether there are indeed objectively undetermined systems raises thorny philosophical questions which are beyond the present discussion. The main difficulty raised by philosophical discussions relevant to determinism lies no doubt in the fact that they must introduce the fiction of an omniscient observer. Now, one may wonder whether this notion does not carry an internal contradiction: how can a non-omniscient observer take the place of an omniscient observer? One can imagine an omniscient observer knowing more than such an observer on this or that subject. But the notion of an omniscient observer supposes that he is informed about subjects the nature of which the real observer might be unable to conceive.