But there is a mode of bringing all this multitude of objects, within the sphere of our narrow sight, in the same manner, as the expanse of landscape, over which the eye would be long in wandering,--the plains, and hills, and woods, and waterfalls,--may be brought, by human art, within the compass of a mirror, far less than the smallest of the innumerable objects which it represents. The process of _gradual generalizing_, by which this reduction is performed, I have already explained to you. Let us now proceed to avail ourselves of it. All the feelings and thoughts of the mind, I have already frequently repeated, are only the mind itself existing in certain states. To these successive states our knowledge of the mind, and consequently our arrangements, which can comprehend only what we know, are necessarily limited. With this simple word _state_, I use the phrase _affection_ of mind as synonymous, to express the momentary feeling, whatever it may be,--with this difference only, that the word _affection_ seems to me better suited for expressing that momentary feeling, when considered as an _effect_,--the feeling itself as a state of the mind, and the relation which any particular state of mind, may bear to the preceding circumstances, whatever they may be that have induced it. Our _states_ of mind, however, or our _affections_ of mind, are the simplest terms, which I can use for expressing the whole series of phenomena of the mind in all their diversity, as existing phenomena, without any mixture of hypothesis, as to the particular mode in which the successive changes may be supposed to arise. When we consider, then, the various states or affections of the mind, which form this series, one circumstance of difference must strike us, that some of them arise immediately, in consequence of the presence of external objects,--and some, as immediately, in consequence of certain preceding affections of the mind itself. The one set, therefore, are obviously the result of the laws both of matter and of mind,--implying, in external objects, a power of affecting the mind, as well as, in the mind, a susceptibility of being affected by them. The other set result from the susceptibilities of the mind itself, which has been formed by its divine Author to exist in certain states, and to exist in these in a certain relative order of succession. The affections of the one class arise, because some external object is present;--the affections of the other class arise, because some previous change in the states of the mind has taken place.