5. I have just said that there exist simple and compound judgments, and that many a compound judgment is not, without a residue, resolvable into simple judgments. Special attention must be paid to this in seeking to convert judgments otherwise expressed into the existential form. It is self-evident that only simple judgments, i.e. such as are, strictly speaking, without parts, are so convertible. I may therefore be excused for not thinking it necessary to emphasize this expressly in my _Psychology_. If this restriction hold good universally it is, of course, valid also of the categorical form. In the propositions categorical in form, which the formal logicians have denoted by the signs A.E.I. and O. they wish to express strictly simple judgments. These are therefore one and all convertible into the existential form (cf. my _Psychology_, vol. i. p. 283). The same, however, will not hold good when propositions categorical in form contain in consequence of an ambiguity of expression (cf. p. 120, note to Appendix) a plurality of judgments. In such a case the existential form may certainly be the expression of a simple judgment equivalent to the compound one, but cannot be the expression of the judgment itself. This is a point which Windelband ought to have considered in examining (p. 184) the proposition: “The rose is a flower” with respect to its convertibility into an existential proposition. He is quite right in protesting against its conversion into the proposition: “There is no rose which is not a flower,” but he is not equally right in ascribing this conversion to me. Neither in the passage cited by him nor elsewhere have I made such a conversion, and I consider it just as false as that attempted by Windelband and all such as may be attempted by anybody else. The judgment here expressed in the proposition is made up of two judgments of which one is the recognition of the subject (whether it be that thereby is meant “rose” in the ordinary sense, or “what is called rose,” “what is understood by rose”), and this, as we have just said, is not always the case where a proposition is given of the form: All A is B. Unfortunately Land also has overlooked this, the only one among my critics who has succeeded in comprehending, in their necessary connection with the principle, what Windelband has termed the “mysterious” hints which I have thrown out towards the reform of elementary logic, and in deducing them correctly from it. (Cf. Land, “On a supposed improvement in Formal Logic” in the papers of the _Kgl. Niederländischen Akademie der Wissenschaften_, 1876.)