The love of power or action is another independent principle of the human mind, in the different degrees in which it exists, and which are not by any means in exact proportion to its physical sensibility. It seems evidently absurd to suppose that sensibility to pleasure or pain is the only principle of action. It is almost too obvious to remark, that sensibility alone, without an active principle in the mind, could never produce action. The soul might lie dissolved in pleasure, or be agonised with woe; but the impulses of feeling, in order to excite passion, desire, or will, must be first communicated to some other faculty. There must be a principle, a fund of activity somewhere, by and through which our sensibility operates; and that this active principle owes all its force, its precise degree of direction, to the sensitive faculty, is neither self-evident nor true. Strength of will is not always nor generally in proportion to strength of feeling. There are different degrees of activity, as of sensibility, in the mind; and our passions, characters, and pursuits, often depend no less upon the one than on the other. We continually make a distinction in common discourse between sensibility and irritability, between passion and feeling, between the nerves and muscles; and we find that the most voluptuous people are in general the most indolent. Every one who has looked closely into human nature must have observed persons who are naturally and habitually restless in the extreme, but without any extraordinary susceptibility to pleasure or pain, always making or finding excuses to do something--whose actions constantly outrun the occasion, and who are eager in the pursuit of the greatest trifles--whose impatience of the smallest repose keeps them always employed about nothing--and whose whole lives are a continued work of supererogation. There are others, again, who seem born to act from a spirit of contradiction only, that is, who are ready to act not only without a reason, but against it--who are ever at cross-purposes with themselves and others--who are not satisfied unless they are doing two opposite things at a time--who contradict what you say, and if you assent to them, contradict what they have said--who regularly leave the pursuit in which they are successful to engage in some other in which they have no chance of success--who make a point of encountering difficulties and aiming at impossibilities, that there may be no end of their exhaustless task: while there is a third class whose _vis inertiæ_ scarcely any motives can overcome--who are devoured by their feelings, and the slaves of their passions, but who can take no pains and use no means to gratify them--who, if roused to action by any unforeseen accident, require a continued stimulus to urge them on--who fluctuate between desire and want of resolution--whose brightest projects burst like a bubble as soon as formed--who yield to every