960 ON HUMAN UNDERSTANDING. 



knowledge to consist of three degrees, placing sensible knowledge, or that 

 obtained by an exercise of the external senses, below the two degree s of 

 intuition and demonstration, though above the authority of opinion. In most 

 instances, however, the ideas we obtain from the senses are as clear and as 

 identic as those obtained from any other source : and in all such case.5 the 

 knowledge they produce is self-evident or intuitive. And although, at times, 

 the idea excited by a single sense may not be perfectly clear, yet, as we 

 usually correct it, or destroy the doubt which accompanies it, by having 

 recourse to another sense, which furnishes us with the proof or intermediate 

 idea, the knowledge obtained, even in these cases, though not amounting to 

 intuition, is of the nature of demonstration : whence all sensible knowledge 

 (the organs of sense being in themselves perfect, and the objects fully within 

 their scope) falls, if I mistake not, under the one or the other of these two 

 divisions. 



DEMONSTRATIVE KNOWLEDGE, where the intervening proofs or ideas perform 

 their part perfectly, approaches, as I have already observed, to the certainty 

 of intuition. But it has generally been held that this kind of demonstration 

 can only take place in the science of mathematics, or, in other words, in ideas 

 of number, extension, and figure. I coincide, however, completely with Mr. 

 Locke, in believing that the knowledge afforded by physics may not unfre- 

 quently be as certain. I have already stated that the knowledge" we possess 

 of our own existence is INTUITIVE, dur knowledge of the existence of a God 

 is, on the contrary, DEMONSTRATIVE. Examine, then, the proofs of this latter 

 knowledge, and see whether it be less certain. Am I asked where proofs to 

 this effect are to be found? On every side they press upon us in clusters. 

 I cannot, indeed, follow them up at the present moment, for it would require 

 a folio volume instead of the close of a single lecture ; and I merely throw 

 out the hint that you may pursue it at home. But this I may venture to say, 

 that whatever cluster we take, it will develope to us a certain proof, and, 

 in its separate value, fall but little short of the force of self-evidence. If I 

 ascend into heaven, he is there ; in peerless splendour, in ineffable majesty ; 

 diffusing, from an inexhaustible fountain, the mighty tide of light, and Hie, 

 and love, from world to world, and from system to system. If I descend into 

 the grave, he is there also ; still actively and manifestly employed in the 

 same benevolent pursuit : still, though in a different manner, promoting the 

 calm but unceasing career of vitality and happiness ; harmoniously leading 

 on the silent circle of decomposition and reorganization : fructifying the cold 

 and gloomy regions of the tomb ; rendering death itself the mysterious source 

 of reproduction and new existence ; and thus literally making the " dry bones 

 live," and the " dead sing praises" to his name. If I examine the world with- 

 out me, or the world within me, I trace him equally to a demonstration : I 

 feel, nay, more thankee/, I&oo>him to be eternal, omniscient, omnipotent, 

 the creator of all things, and therefore God. I discover him, riot by the vain 

 maxims of tradition, or the visionary conceit of innate principles, but by the 

 faculty with which he has expressly endowed me to search for him, by my 

 reason. There may, perhaps, be some persons, as well learned as unlearned, 

 who have never brought together these proofs of his existence, and are 

 therefore ignorant of him ; as there certainly are others who have never 

 brought together the proofs that the three angles of a triangle are equal to 

 two right angles, and are therefore ignorant of geometry : but both facts have 

 a like truth and a like foundation : both flow from and return to the same 

 fountain : for God is the author of every truth, for God is truth itself. 



