ON HUMAN UNDERSTANDING. 399 



that we may hasten with due speed to the goal before us. Allow me, 

 however, before we quit it, to observe that words bear precisely the same 

 relation to ideas that ideas do to objects ; for as ideas are the mere signs 

 of objects, so words are the mere signs of ideas ; and hence that every 

 rule which applies to the variety, precision, and arrangement of our ideas, 

 applies with equal force to the variety, precision, and arrangement of our 

 words ; and that without a clear and determinate meaning to the latter, 

 we can no more have a clear and determinate appreher;sion of the former 

 than we can have of a person's features by a confused or unlike picture. 

 And hence the importance of attending to our vocabulary ; of minutely 

 measuring and weighing the terms we make use of, so as to adjust them 

 exactly to the measure and weight of our ideas, must be obvious at the 

 first glance ; as it must be also, that the more exact and copious a lan- 

 guage is found, the more clear and comprehensive must be the general 

 knowledge of the nation to which it belongs. 



But ideas and words, though the materials of which knowledge is con- 

 structed, and without which it cannot among mankind be constructed at 

 all, are no more knowledge itself, than the bricks and mortar of a house 

 are the house itself. Both, as I have indeed hinted at already, must be 

 collected in sufficient abundance, compared with each other, duly assort- 

 ed, arranged and united together, before the proper building can be pro- 

 duced ; and we have yet, therefore, to contemplate the most important 

 part of the subject before us, and that to which the preceding parts are 

 subservient — the general nature of knowledge, its kinds, degrees and 

 reality. 



Knowledge may be defined the perception of truth, or in the lan- 

 guage of Aristotle, the science of truth ; and consequently he who 

 acquires knowledge, perceives or acquires truth. But what is truth? This 

 is a question which has been asked for ages : the particular answer, how- 

 ever, must necessarily depend upon the particular subject to which it re- 

 fers. We are now considering general truths which may be defined 

 the connexion and agreement, or repugnancy and disagreement, of our 

 ideas. 



This definition requires some attention ; but when it is thoroughly com- 

 prehended, it will be found to apply to truths of every kind, in the arts, 

 physics, and morals, as well as in metaphysics ; for the law of adjustment, 

 of connexion and disconnexion, of congruity and incongruity it refers to, 

 is an universal law or constitution of nature, and hence must hold equally 

 every where. Thus in a building, where the different parts of which it 

 consists perfectly agree, the lines accurately correspond, and the depen- 

 dencies fit and are proportioned to each other : every part is true to every 

 part, and the whole is true to itself. 



So in working a mathematical problem, or determining a fact from cir- 

 cumstantial evidence, every separate hnk or idea that constitutes a part 

 of the general chain, must have its proper connexion or agreement with 

 the link or idea that lies next to it, as well above as below ; for it is these 

 connexions or agreements between one idea and another that constitute 

 the proofs, and a failure in any one destroys our knowledge upon the sub- 

 ject ; or, in other words, prevents us from perceiving its truth. 



It sometimes happens, that we are able to discover at once, this agree- 

 ment or disagreement, this connexion or repugnancy, in the ideas that are 

 presented to us ; and in such case our ^knowledge is instantaneous, and 

 -constitutes what we call intuition or intuitive knowledoe. But it 



