PHILOSOPHY, MENTAL. 



the first case, respecting- the causes and 

 effects of such recurrence. 



57. On the whole it may appear to the 

 reader, that the simple ideas of sensation 

 must run into clusters and combinations, 

 by association ; and that each of these 

 \vill, at last, coalesce into one compound 

 or complex idea. It appears also from 

 observation, that many of our mental or 

 intellectual ideas (that is, those in which no 

 particular idea of sensation is perceptible) 

 such as those which belong- to the heads 

 of beauty, honour, moral qualities, &c. are, 

 in fact, thus composed of parts, which by 

 degrees coalesce into one complex idea. 

 And as this coalescence of simple into 

 complex ideas is thus evinced, both by the 

 theory of association and by observation, 

 so it may be illustrated and further con- 

 firmed, by the similar coalescence of let- 

 ters into syllables and words, in which as- 

 sociation is likewise a chief instrument. 



58- If the number of simple ideas which 

 compose the complex idea be very great, 

 it may happen that the complex ideas shall 

 not appear to bear any relation to its com- 

 ponent parts, nor to the external senses by 

 which the original sensations were receiv- 

 ed. The reason of this is, that each sin- 

 gle idea is overpowered by the sum of all 

 the rest, as soon as they are all intimately 

 united together Thus in very compound 

 medicines, the several tastes and Havours 

 of the separate ingredients are lost and 

 overpowered by the complex one of the 

 whole mass : so that this has a taste and 

 flavour of its own, which appears to be 

 simple and original. Thus also white ap- 

 pears, and is vulgarly thought to be, the 

 simplest of ail colours, while yet it really 

 arises from a certain mixture of the seven 

 primary colours in their due shades and 

 proportions. And to resume the illustra- 

 tion above-mentioned, to one unacquaint- 

 ed with the arts of readingand writing, it 

 could not appear probable, that the great 

 variety of complex sounds in language are 

 to be analysed into a few simple sounds. 

 One may hope, therefore, that by pursu- 

 ing and perfecting the doctrine of associa- 

 tion, we may some time or other be ena- 

 bled to analyse all that vast variety of 

 complex ideas which pass under the names 

 of ideas of reflection, abstract ideas, de- 

 sires, affections, &c, into their simple com- 

 ponent parts, that is, into the simple ideas 

 of sensation of which they are formed. 

 This would be greatly analogous to the 

 representation of complex articulate 

 sounds by alphabetical signs, and to the 

 revolution of colours, or of natural bodies, 

 into their simple constituent parts. The 



complex ideas here spoken of are gene- 

 rally excited by words or visible objects ; 

 but they are also connected with other 

 external impressions, and depend upon 

 them as symbols. In whatever way we 

 consider them, the trains of them which 

 are presented to the mind seem to depend 

 upon the then present state of the body, 

 the external impressions and the remain- 

 ing influence of prior impressions and as- 

 sociations taken together. 



59 As simple ideas of sensation run in- 

 to complex ones by association, so com- 

 plex ideas run into decomplex ones by 

 association. Hut here the varieties of the 

 associations, which increase with the com- 

 plexi'y, hinder particular ones from being 

 so close and permanent between the com- 

 plex parts of decomplex ideas, as between 

 the simple parts of complex ones. 



60 The simple ideas of sensation arc 

 not all equally and uniformly concerned 

 in forming complex and decomplex ideas, 

 but, on tlie contrary, some occur much 

 oftener than others ; and the same holds 

 good of complex ideas as the component 

 parts of decomplex ideas : and innumer- 

 able combinations never occur at all in 

 real life, and consequeutly are never asso- 

 ciated into complex and decomplex ideas. 

 Just as in languages, some letters, and 

 combinations of letters, occur much more 

 frequently than others, and some combi- 

 nations never occur at all. Further, as 

 persons who speak the same language 

 have, however, a different use and extent 

 of words, so, though mankind in all ages 

 and nations agree, in general, in their 

 complex and decomplex ideas, yet there 

 are many particular differences in them, 

 and these differences are greater or less, 

 according to the difference or resemblance 

 in age, constitution, education, profession, 

 country, period, &c. that is, in their im- 

 pressions and associations. 



61. When sensations and ideas, with 

 their most common combinations, have 

 been often presented to the mind, a train 

 of them, of considerable length, may, by 

 once occurring, produce such a tendency 

 to recurrence, that they may recur, with- 

 out the previous cause, in nearly the same 

 order and proportion as in this single oc- 

 currence. For since each of the particu- 

 lar sensations and ideas is familiar, little 

 more will be wanting for their recurrency 

 than a few connecting links : and even 

 these may, in some instances, be supplied 

 by former similar instances. These con- 

 siderations, when duly unfolded, seem to 

 explain the chief phenomena of memory ; 

 and it will be easily seen from them, that 



