Discussion and conclusion. - The established results are confronted with quantum mechanics, with (D+A) and with experiment. It is asserted that since quantum mechanics is in contradiction with all the demonstrated inequalities if quan- tum mechanics were found true by experiment the conception according to which "when a proposition is true on a system S this constitutes an intrin- sic property of S, which can be neither imparted to S nor withdrawn from S as long as S is isolated" (i.e. (D+A)) would have to be dropped (the summary). Furthermore, Einstein's principle of separability is recalled: if S, and S, have interacted in the past but are now arbitrarily far from one another "the real, factual situation of system S, does not depend on what is done with system S, which is spatially separated from the former" 3. It is asser- ted that the truth of this principle can be decided by the same experimental tests which are able to decide on the truth of (D+A), namely those on Bell's or similar inequalities.

We consider the propositions: p1 : S is isolated

P2 : S possesses intrinsic persistent properties, which together with any given apparatus used for some measurements on S, determine entirely the in- dividual results of these measurements, indepen- dently of the state of any other system or other apparatus.

P3 : Bell's inequalities are verified.

The notations X, X, => bo A, V mean respectively: the proposition x is true, the proposition x is false, and the logical implication, conjunction, disjunction. When p., P2 or p, concerns exclusive- ly a system Se (U,V where U and V are the two parts of a composite system U+Ve EU+V we write respectively p, (U,V), p. (U,V) or p, (U,V). 2 The object of study in d'Espagnat's work con-