Now apprehension, as I have said, has two subject-matters:—according as language expresses things external to us, or our own thoughts, so is apprehension real or notional. It is notional in the grammarian, it is real in the experimentalist. The grammarian has to determine the force of words and phrases; he has to master the structure of sentences and the composition of paragraphs; he has to compare language with language, to ascertain the common ideas expressed under different idiomatic forms, and to achieve the difficult work of recasting the mind of an original author in the mould of a translation. On the other hand, the philosopher or experimentalist aims at investigating, questioning, ascertaining facts, causes, effects, actions, qualities: these are things, and he makes his words distinctly subordinate to these, as means to an end. The primary duty of a literary man is to have clear conceptions, and to be exact and intelligible in expressing them; but in a philosopher it is even a merit to be not altogether vague, inchoate and obscure in his teaching, and if he fails even of this low standard of language, we remind ourselves that his obscurity perhaps is owing to his depth. No power of words in a lecturer would be sufficient to make psychology easy to his hearers; if they are to profit by him, they must throw their minds into the matters in discussion, must accompany his treatment of them with an active, personal concurrence, and interpret for themselves, as he proceeds, the dim suggestions and adumbrations of objects, which he has a right to presuppose, while he uses them, as images existing in their apprehension as well as in his own. In something of a parallel way it is the least pardonable fault in an Orator to fail in clearness of style, and the most pardonable fault of a Poet. So again, an Economist is dealing with facts; whatever there is of theory in his work professes to be founded on facts, by facts alone must his sense be interpreted, and to those only who are well furnished with the necessary facts does he address himself; yet a clever schoolboy, from a thorough grammatical knowledge of both languages, might turn into English a French treatise on national wealth, produce, consumption, labour, profits, measures of value, public debt, and the circulating medium, with an apprehension of what it was that his author was stating sufficient for making it clear to an English reader, while he had not the faintest conception himself what the treatise, which he was translating really determined. The man uses language as the vehicle of things, and the boy of abstractions.