Nature hath guarded man, her favourite, against a succession too rapid, not less carefully than against one too slow. Both are equally painful, though the pain is not the same in both. Many are the good effects of this contrivance. In the first place, as the bodily faculties are by certain painful sensations confined within proper limits, beyond which it would be dangerous to strain the tender organs, Nature, in like manner, is equally provident with respect to the nobler faculties of the mind. Thus the pain of an accelerated course of perceptions, is Nature’s admonition to relax our pace, and to admit a more gentle exertion of thought. Another valuable purpose may be gathered, from considering in what manner objects are imprinted upon the mind. To make such an impression as to give the memory fast hold of the object, time is required, even where attention is the greatest; and a moderate degree of attention, which is the common case, must be continued still longer to produce the same effect. A rapid succession then must prevent objects from making impressions so deep as to be of real service in life; and Nature accordingly for the sake of memory, has by a painful feeling guarded against a rapid succession. But a still more valuable purpose is answered by this contrivance. As, on the one hand, a sluggish course of perceptions indisposeth to action; so, on the other, a course too rapid impels to rash and precipitant action. Prudent conduct is the child of deliberation and clear conception, for which there is no place in a rapid course of thought. Nature therefore, taking measures for prudent conduct, has guarded us effectually from precipitancy of thought, by making it painful. Nature not only provides against a succession too slow or too quick, but makes the middle course extremely pleasant. Nor is this middle course confined within narrow bounds. Every man can naturally without pain accelerate or retard in some degree the rate of his perceptions; and he can do this in a still greater degree by the force of habit. Thus a habit of contemplation annihilates the pain of a retarded course of perceptions; and a busy life, after long practice, makes acceleration pleasant.