As the multitude of common nouns have originally been singular, it is not surprising that many of them should so remain still in the apprehension of particular individuals. In the proposition “Sugar is sweet,” the predicate is a common noun as used by those who have compared sugar in their thoughts with honey or glycerine; but it may be the only distinctively sweet thing in the experience of a child, and may be used by him as a noun singular. The first time that he tastes sugar, if his nurse says, “Sugar is sweet” in a notional sense, meaning by sugar, lump-sugar, powdered, brown, and candied, and by sweet, a specific flavour or scent which is found in many articles of food and many flowers, he may answer in a real sense, and in an individual proposition “Sugar is sweet,” meaning “this sugar is this sweet thing.” Thirdly, in the same mind and at the same time, the same proposition may express both what is notional and what is real. When a lecturer in mechanics or chemistry shows to his class by experiment some physical fact, he and his hearers at once enunciate it as an individual thing before their eyes, and also as generalized by their minds into a law of nature. When Virgil says, “Varium et mutabile semper fœmina,” he both sets before his readers what he means to be a general truth, and at the same time applies it individually to the instance of Dido. He expresses at once a notion and a fact. Of these two modes of apprehending propositions, notional and real, real is the stronger; I mean by stronger the more vivid and forcible. It is so to be accounted for the very reason that it is concerned with what is either real or taken for real; for intellectual ideas cannot compete in effectiveness with the experience of concrete facts. Various proverbs and maxims sanction me in so speaking, such as, “Facts are stubborn things,” “Experientia docet,” “Seeing is believing;” and the popular contrast between theory and practice, reason and sight, philosophy and faith. Not that real apprehension, as such, impels to action, any more than notional; but it excites and stimulates the affections and passions, by bringing facts home to them as motive causes. Thus it indirectly brings about what the apprehension of large principles, of general laws, or of moral obligations, never could effect. ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ Reverting to the two modes of holding propositions, conditional and unconditional, which was the subject of the former Section, that is, inferences and assents, I observe that inferences, which are conditional acts, are especially cognate to notional apprehension, and assents, which are unconditional, to real. This distinction, too, will come before us in the course of the following chapters. And now I have stated the main subjects of which I propose to treat; viz., the distinctions in the use of propositions, which I have been drawing, and the questions which those distinctions involve.