 The introduction of the notion of the unique meaning of a sentence leads Twardowski to make a further distinction between substitutive (artefacta) and non-substitutive judgments. Substitutive judgments aren't real judgments, but fictitious ones. The latter are in fact the presented judgments of Content and Object; the difference is that in Actions and Products, Twardowski applies the concept of substitutive judgments explicitly to logic: the sentences uttered or written by logicians-at-work are not sentences which express or have as meanings judgments which are really passed by them, but only presented judgments, produced thus by actions of presenting—which are different actions from actual judging acts. This happens for instance when a logician constructs a valid syllogism made up of materially false sentences to give examples of formally valid inferences (§44, 130). In this case, the logician does not actually judge that all triangles are square, that all squares are round, and that all triangles are round, but she merely presents the corresponding judgments. The sentences ‘all triangles are square,’ ‘all squares are round,’ and ‘all triangles are round’ are not real sentences, but artificial ones, because they are “expressions of artificial products that substitute for actual judgments, namely merely represented judgments” (Ibid.). The meanings of these artificial sentences are artificial judgments, because they are merely presented, not passed. These artificial judgments are the subject-matter of logic (on this point, Twardowski is again indebted to Bolzano). Operating with surrogate sentences such as ‘all triangles are square’ constitutes the most extreme example of “making mental products independent of the actions owing to which alone they can truly (actually) exist” (§44, 131). 