That we may enter more particularly into the causes of this confusion, and con sequently be the better enabled to pre vent it, let us consider words according to the four classes above mentioned.
Now, mistakes will happen in words of the first class, viz. such as have ideas only, where the persons have associated these words with different impressions. And the method to rectify any mistake of this kind is, for each person to show with what actual impressions he has asso ciated the word in question. But mis takes here are not common.
In words of the second class, viz. such as have both ideas and definitions, it of ten happens that one person's knowledge is much more full than another's, and consequently his idea and definition much more extensive. This must cause a mis apprehension on one side, which yet may be easily rectified by recurring to the definition. It happens also sometimes in words of this class, that a man's ideas are not always suitable to his definition; that is, are not the same with those which the words of the definition would excite. If then this person should pretend, or even design, to reason from his definition, and yet reason from his idea, misapprehen sion will arise in the hearer, who sup poses him to reason from his definition merely.
In words of the third class, which have definitions only and no immediate ideas; mistakes generally arise through want of fixed definitions being mutually ackno• ledged and kept to. However, as imper fect fluctuating ideas that have little re lation to the definitions, are often apt to adhere to the words of this class, mis takes must arise from this cause also.
As to the words of the fourth class, or those which have neither ideas nor cleft nitions, it is easy to ascertain their use by inserting them in sentences where import is known and acknowledged, this being the method in which children learn to decypher them ; so that mistakes could not arise in the words of this class, did we use moderate care and candour. And, indeed, since children learn the uses of words most evidently without having any data, any fixed point at all, it is to be hoped that philosophers and candid per sons may learn at least to understand one another with fitcility and certainty ; and get to the very bottom of the connection between words and ideas.
4. When 'words have acquired any con siderable power of exciting pleasant or painful feelings, by being often associat ed with such things as do this, they may transfer a part of their pleasures and pains upon indifferent things, by being at other times often associated with such. This is one of the principal sources of the several factitious pleasures and pains of human life. Thus, to give an instance from childhood, the words sweet, good, pretty, ,fine, &c. on the one hand ; and the words bad, itgly,frightfd, &c. on the other, being applied by the nurse and at tendants in the child's hearing, almost promiscuously, and without those restric tions that are observed in correct speak ing ; the one set to all the pleasures, the other to all the pains, of the several senses, must by association up ge neral pleasant and painful feelings, in which no one part can be distinguished above the rest ; and when applied by further associations to objects of a neu tral kind, they must transfer a general pleasure or pain upon them.
5. Since words thus collect ideas from various quarters, unite them together, and transfer them, both upon other words and upon foreign objects, it is evident that the use of words adds much to the number and complexity of our ideas, and is the principal means by which we make mental and moral improvement. This is verified abundantly by the observations which are made upon persons born deaf; and continuing so. It is probable, how ever, that these persons make use of some symbols to assist the memory, and fix the imagination ; and they must have a great of pleasures and pains transferred upon visible objects, from their associations with one another, and with sensible pleasures of all kinds ; but they are very deficient in this, upon the whole, through the want of the associa bulls of visible, objects and states of mind, &c. with words. Learning to read must add greatly to their mental improvement ; yet still their intellectual capacities can not but remain very narrow.
Persons blind from birth must proceed in a manner different from that before described, in the first ideas which they affix to words. As the visible ones are wanting, the others, particularly the tan gible and audible ones, must compose the aggregates which are annexed to words. However, as they are capable of learning and retaining as great a variety of words as others, and can associate with them pleasures and pains from the four remain ing senses; they fall little or nothing short of others in intellectual accomplishments, and may arrive even at a greater degree of spirituality and abstraction in their complex ideas.
6. Hence it follows, that when children, or others, first learn to read, the view of the words excites ideas only by the me diation of their sounds, with which alone their ideas have hitherto been associated. And thus it is that children and illiterate persons best understand what they read by reading aloud. By degrees, the inter mediate links being left out, the written or printed characters suggest the ideas directly and instantaneously; so that per sons who are much in the habit of reading, understand more readily by passing over the words with the eye only ; since this method, by being more expeditious, brings the ideas closer together. How ever, all are peculiarly affected by words pronounced in a manner suitable to their sense and design ; which is still an associ ated influence.