The form of words which expresses a predication is a proposition. Hence, every predication is the verbal equivalent of a belief; and, as every belief is either an immediate consciousness, a memory, or an expectation, and as every expectation is traceable to a memory, it follows that, in the long run, all propositions express either immediate states of consciousness, or memories. The proposition which predicates A of X must mean either, that the fact is testified by my present consciousness, as when I say that two colours, visible at this moment, resemble one another; or that A is indissolubly associated with X in memory; or that A is indissolubly associated with X in expectation. But it has already been shown that expectation is only an expression of memory. Hume does not discuss the nature of language, but so much of what remains to be said, concerning his philosophical tenets, turns upon the value and the origin of verbal propositions, that this summary sketch of the relations of language to the thinking process will probably not be deemed superfluous. So large an extent of the field of thought is traversed by Hume, in his discussion of the verbal propositions in which mankind enshrine their beliefs, that it would be impossible to follow him throughout all the windings of his long journey, within the limits of this essay. I purpose, therefore, to limit myself to those propositions which concern--1. Necessary Truths; 2. The Order of Nature; 3. The Soul; 4. Theism; 5. The Passions and Volition; 6. The Principle of Morals. Hume's views respecting necessary truths, and more particularly concerning causation, have, more than any other part of his teaching, contributed to give him a prominent place in the history of philosophy. "All the objects of human reason and inquiry may naturally be divided into two kinds, to wit, _relations of ideas_ and _matters of fact_. Of the first kind are the sciences of geometry, algebra, and arithmetic, and, in short, every affirmation which is either intuitively or demonstratively certain. _That the square of the hypothenuse is equal to the square of the two sides_, is a proposition which expresses a relation between these two figures. _That three times five is equal to the half of thirty_, expresses a relation between these numbers. Propositions of this kind are discoverable by the mere operation of thought without dependence on whatever is anywhere existent in the universe. Though there never were a circle or a triangle in nature, the truths demonstrated by Euclid would for ever retain their certainty and evidence.