Page:Observations on Man 1834.djvu/84

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and connects them together. In this it somewhat resembles the first letter of a word, or first word of a sentence, which are often made use of to bring all the rest to mind.

Cor. VIII. When objects and ideas, with their most common combinations, have been often presented to the mind, a train of them, of a considerable length, may, by once occurring, leave such a trace, as to recur in imagination, and in miniature, in nearly the same order and proportion as in this single occurrence. For, since each of the particular impressions and ideas is familiar, there will want little more for their recurrency, than a few connecting links; and even these may be, in some measure, supplied by former similar instances. These considerations, when duly unfolded, seem to me sufficient to explain the chief phænomena of memory; and it will be easily seen from them, that the memory of adults, and masters in any science, ought to be much more ready and certain than that of children and novices, as it is found to be in fact.

Cor. IX. When the pleasure or pain attending any sensations and ideas is great, all the associations belonging to them are much accelerated and strengthened. For the violent vibrations excited in such cases, soon overrule the natural vibrations, and leave in the brain a strong tendency to themselves, from a few impressions. The associations will therefore be cemented sooner and stronger than in common cases; which is found agreeable to the fact.

Cor. X. As many words have complex ideas annexed to them, so sentences, which are collections of words, have collections of complex ideas, i.e. have decomplex ideas. And it happens, in most cases, that the decomplex idea belonging to any sentence is not compounded merely of the complex ideas belonging to the words of it; but that there are also many variations, some oppositions, and numberless additions. Thus, propositions, in particular, excite, as soon as heard, assent or dissent; which assent and 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 the matter, to shew in what manner, and by what steps, i.e. by what impressions and associations, our assent and dissent, both in scientifical and moral subjects, is formed.


Prop. XIII.—When simple Ideas run into a complex one, according to the foregoing Proposition, we are to suppose, that the simple miniature Vibrations corresponding to those simple Ideas, run in like manner, into a complex miniature Vibration, corresponding to the resulting complex Idea.


This proposition is analogous to the ninth and eleventh, and may be deduced from the last, as they are from the eighth and