soluble in aqua regia, farther in those who penetrate still deeper into abstract speculations. And hence we may see, as before, First, That terms or words are absolutely necessary to the art of reasoning: Secondly, That our assent is here also, in every step of the process, deducible from association.
The propositions formed concerning natural bodies are often attended with a high degree of practical assent, arising chiefly from some supposed utility and importance, and which is no ways proportionable to the foregoing, or other such like allowed causes of rational assent. And in some cases the practical assent takes place before the rational. But then, after some time the rational assent is generated and cemented most firmly by the prevalence of the practical. This process is particularly observable in the regards paid to medicines, i.e. in the rational and practical assent to the propositions concerning their virtues.
It is to be observed, that children, novices, unlearned persons, &c. give, in many cases, a practical assent upon a single instance; and that this arises from the first and simplest of the associations here considered. The influence of the practical assent over the rational arises plainly from their being joined together in so many cases. The vividness of the ideas arising from the supposed utility, importance, &c. does also unite the subject and predicate sooner and closer, agreeably to what has been observed in the general account of association.
The evidences for past facts are a man’s own memory, and the authority of others. These are the usual associates of true past facts, under proper restrictions, and therefore beget the readiness to affirm a past fact to be true, i.e. the rational assent. The integrity and knowledge of the witnesses, being the principal restriction, or requisite, in the accounts of past facts, become principal associates to the assent to them; and the contrary qualities to dissent.
If it be asked, how a narration of an event supposed to be certainly true, supposed doubtful, or supposed entirely fictitious, differs in its effect upon the mind, in the three circumstances here alleged, the words being the same in each, I answer, first, in having the terms true, doubtful, and fictitious, with a variety of usual associates to these, and the corresponding internal feelings of respect, anxiety, dislike, &c. connected with them respectively; whence the whole effects, exerted by each upon the mind, will differ considerably from one another. Secondly, If the event be of an interesting nature, as a great advantage accruing, the death of a near friend, the affecting related ideas will recur oftener, and by so recurring agitate the mind more, in proportion to the supposed truth of the event. And it confirms this, that the frequent recurrency of an interesting event, supposed doubtful, or even fictitious, does, by degrees, make it appear like a real one, as in reveries, reading romances, seeing plays, &c. This affection of mind may be called the practical assent to past facts;
