CATEGORICAL PROPOSITIONS

Seventeenth-century logicians commonly adhered to the usual distinction between two operations of the mind: on the one hand, simple conceptions, through which things are apprehended that, as categorematic terms, are capable of becoming the subject and the predicate of a categorical proposition; on the other, acts of predication, by which the contents of simple apprehensions are combined into a propositional complex that is a suitable potential object of assent or dissent. Although at the propositional level acts of predication and judgement will often coincide, authors were aware that there are good reasons to distinguish merely apprehensive propositions from judicative propositions. The former are states of affairs that are presented to the mind without any commitment to truth or falsity, whereas the latter actually have judicative or assertive force. Notwithstanding the predominant tendency to stick to the traditional division into incomplex concepts and propositional complexes, there were also factors at work which made for blurring of that fundamental distinction. One of them was Descartes's use of the word idea for both the categorematic elements of a proposition and the proposition itself, as the object of judgement. Spinoza went even farther by explicitly declaring that at bottom a particular idea and a particular act of affirming or denying are one and the same thing. When, for example, the mind affirms that the sum of the three angles of a triangle is equal to two right angles, that affirmation cannot exist or be thought without the idea of a triangle.