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In an earlier article I called attention to the fact that Mill stated that since abstract terms are sometimes singular and sometimes general , it might be better to put them in a "class apart." I argued that this class apart was that of universal if-then propositions; abstract terms being, when they have logical import, the content of such propositions. I stated that confusion has arisen in logical theory because such propositions are not definitely and consistently marked off from propositions that are general in the sense of generic, that is, referring to kinds, the latter being designated linguistically by common nouns instead of abstract nouns. I added that "contemporary logical writings are full of the confusion of the generic (general) and the universal, in spite of the common nominal recognition of the ambiguity ofall."1 I propose here to illustrate this last statement as a means of effecting recognition of a difference in logical form between two kinds of propositions both of which are termed genera1.2 The nature of classes is introduced by Miss Stebbing by means of an example, the class of scholars. It is said that "scholars are all the individuals who are learned, viz., a set of individuals distinguished from other sets of individuals in that each individual of the set possesses the property of being learned."3 The set determined by a property or a conjunction of properties is said to constitute a class. Later, we find the statements "General propositions are about properties which individual objects may possess"; and "Every property determines a class, namely, the class consisting of the objects which possess the property."4 I am not citing these passages to take objection to them. On the contrary, Miss Stebbing brings out clearly the important fact that general propositions are directly about a relation of properties and indirectly about objects having these properties. Moreover, the text goes on to indicate the logical difference between A and E propositions on one side, and I and 0 propositions on the other. The former can be understood if we "understand what is meant by being an 5 and a P. Hence it is convenient to interpret them as not implying the existence of 5."5 I and 0 propositions, on the other hand, do imply (refer to, or postulate) existence. There is, of course, no objection to be General Propositions, Kinds, and Classes (1936) 151 taken to these statements. But what one would expect to follow from them is that there is a basic logical difference between general propositions about properties, determining a kind of objects marked by these properties, and the ifthen propositions that do not "imply" the existence of objects. What one naturally expects is that it would be affirmed that the former are necessarily of the I and 0 form and the latter alone of the A and E form. But this distinction between the two types of general propositions is not drawn. It would also seem to follow that a distinction should be made between the concept of "classes" as determined by propositions of the first form, and the logical concept of whatever it is that is determined by the if-then A and E universal propositions.6 Such, however, are not the conclusions drawn. Both types of propositions are treated as general propositions and that which is determined by propositions of the two forms is indiscriminately termed a class. As far as can be made out, the ground for the identification is as follows: The sound idea that generic propositions are directly concerned with properties which refer to the whole range of objects that may possess them, not to any given one thing among them, is gradually converted into the idea that such propositions have no inherent existential reference at all. This conclusion is thought to be supported by the further (undeniable ) fact that in the case of some generic propositions, for example, those about centaurs , sea-serpents, etc., there are in point of fact no existences to which they can refer. 1. As to the first point. It is truly said that "we can assert 'all men are mortal' although we are certainly not acquainted with each individual man." It is also said that "no actual man enters into the assertion since the assertion is true whether any given man is known or not," for "a property or characteristic is being considered in abstraction from the individual or individuals to which it may refer."7 Is there not...

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