This seems further to show, that passive impressions made upon our minds by admonition, experience, or example, though they may have a remote efficacy, and a very great one, towards forming active habits, yet can have this efficacy no otherwise than by inducing us to such a course of action: and that it is not being _affected_ so and so, but acting, which forms those habits: only it must be always remembered, that real endeavors to enforce good impressions upon ourselves are a species of virtuous action. Nor do we know how far it is possible, in the nature of things, that effects should be wrought in us at once, equivalent to habits; _i.e._ what is wrought by use and exercise. The thing insisted on is, not what may be possible, but what is in fact the appointment of nature: which is, that active habits are to be formed by exercise. Their progress may be so gradual, as to be imperceptible in its steps: it may be hard to explain the faculty, by which we are capable of habits, throughout its several parts; and to trace it up to its original, so as to distinguish it from all others in our mind: and it seems as if contrary effects were to be ascribed to it. But the thing in general, that our nature is formed to yield to use and exercise, in some such manner as this, is matter of certain experience. Thus, by accustoming ourselves to any course of action, we get an aptness to go on, a facility, readiness, and often pleasure, in it. The inclinations which rendered us averse to it, grow weaker; the difficulties in it, not only the imaginary but the real ones, lessen; the reasons for it offer themselves of course to our thoughts upon all occasions; and the least glimpse of them is sufficient to make us go on, in a course of action, to which we have been accustomed. Practical principles appear to grow stronger, absolutely in themselves, by exercise; as well as relatively, with regard to contrary principles; which, by being accustomed to submit, do so habitually, and of course. Thus a new character, in several respects, may be formed; and many habitudes of life, not given by nature, but which nature directs us to acquire. III. Indeed we may be assured, that we should never have had these capacities of improving by experience, acquired knowledge, and habits, had they not been necessary, and intended to be made use of. And accordingly we find them so necessary, and so much intended, that without them we should be utterly incapable of that which was the end for which we were made, considered in our temporal capacity only: the employments and satisfactions of our mature state of life.