62. As many words have complex ideas annexed to them, so sentences, which are collections of words, have collections of complex ideas, that is, have decomplex ideas. And it happens in most cases, that the decomplex idea belonging to any sen tence, is not compounded merely to the complex ideas belonging to the words of it ; but that there are also many variations, some oppositions, and numberless addi tions. Thus propositions, in particular, excite, as soon as heard, assent or dissent; which assent or dissent consist chiefly of additional complex ideas not included in the terms of the proposition. And it would be of the greatest use both in the sciences and in common life, thoroughly to analyse this matter, to show in what manner, and by what steps, that is, by what impressions and associations our assent and dissent, both in scientifical and moral subjects, is formed.
Respecting the Vividness of complex Ideas, and the intellectual Pleasures and Pains in general.
63. It is reasonable to think, that some ideas may be as vivid as any sensation ex cited by the direct action of objects upon the external organs of sense. For com plex ideas may consist of so many parts, and these may so alter and exalt one an other, that the sensorial change (whatever that be), may be as great as can be pro duced by any single external impression. And we know, as a matter offset, that men tal pains are sometimes so acute as to coun terbalance, and even altogether remove, the attention from the most excruciating pain, which is merely that of sensation. This process may be assisted and accelerated by the mixture of vivid sensations among the ideas, by the sensibility of the mental frame, by a predisposition to a particular class of ideas, &c.—It is on this principle, in connection with the preceding state ment, that we are enabled to account for the existence of intellectual or mental pleasures and pains (that is, those in which no particular sensible pleasure or pain is perceptible), which form a distinct and a most important class of feelings. The quality of sensible pleasures or pains, that is, of pleasurable or painful sensations, unite and coalesce in the same manner as other ideas ; and variously connected and blended together, they constitute the whole of those internal feelings which we call passions, affections, emotions, &c.— In almost every step of our investigations in mental philosophy, we are perplexed by the scantiness of language, and still more by the want of precision with which the words we have are employed. It is
much more easy to point out faults than to correct them ; but it appears to us like ly to promote the object in one depart ment, if the two classes of ideas (the re licts of sensations), viz. those which are pleasureable or painful, and those which are indifferent, or, more properly, which belong to the understanding, were deno minated, the latter notions, the former feelings. Popular language would, in a great measure, have borne us out in this appropriation ; but, at least in the com mencement of our statements, we were obliged to employ feelings in a more ge neral sense, viz. for every sensorial change attended with consciousness, because we have no other word in the language com prehending ideas and sensations : hence forwards, however, we wish to appropriate the word feelings to those complex ideas which are either pleasureable or painful, so as to correspond with Hartley's deno mination "intellectual or mental pleasures and pains," including, as he appears to do, the affections and passions.
64. It appears from the preceding sec tion, that the mental pleasures and pains may be equal to, or greater or less than, the sensible ones, according as each per son unites more or fewer, more vivid or more languid ideas in the formation of the mental pleasures and pains.
65. It is of the utmost consequence to morality and religion, that the feelings should be analyzed into their simple com ponent parts, by reversing the steps of the associations which concur to form them. For thus we may learn how to cherish and improve good ones, to check and root out such as are mischievous and immoral, and how to suit our manner of life, in some tolerable measure, to our in tellectual and religious wants. And as this holds, in respect of persons of all ages, so it is particularly true and worthy of consideration in respect or children and youth. The world is, indeed, suffi ciently stocked with general precepts for this purpose, grounded on experience ; and whosoever will follow these faithful ly may expect good general success. However, the doctrine of association, whe,n traced up to the first rudiments of understanding and affection, unfolds such a scene as cannot fitil both to instruct and alarm all such as have any degree of in. terested concern for themselves, or of a benevolent one for others.