Man being unavoidably connected with the beings around him, some acquaintance with their nature, their powers, and their qualities, is requisite for regulating his conduct. As an incentive to acquire a branch of knowledge so essential to our well-being, motives alone of reason and interest are not sufficient. Nature hath providently superadded curiosity, a vigorous propensity which never is at rest. It is this propensity which attaches us to every new object[78]; and in particular incites us to consider objects in the way of comparison, in order to discover their differences and resemblances. Resemblance among objects of the same kind, and dissimilitude among objects of different kinds, are too obvious and familiar to gratify our curiosity in any degree. The gratification lies in discovering differences among things where resemblance prevails, and in discovering resemblances where difference prevails. Thus a difference in individuals of the same kind of plants or animals is deemed a discovery, while the many particulars in which they agree are neglected: and in different kinds, any resemblance is greedily remarked, without attending to the many particulars in which they differ. A comparison however may be too far stretched. When differences or resemblances are carried beyond certain bounds, they appear slight and trivial; and for that reason will not be relished by one of taste. Yet such propensity is there to gratify passion, curiosity in particular, that even among good writers, we find many comparisons too slight to afford satisfaction. Hence the frequent instances among logicians, of distinctions without any solid difference: and hence the frequent instances among poets and orators, of similes without any just resemblance. With regard to the latter, I shall confine myself to one instance, which will probably amuse the reader, being a citation not from a poet nor orator, but from a grave author writing an institute of law. “Our student shall observe, that the knowledge of the law is like a deep well, out of which each man draweth according to the strength of his understanding. He that reacheth deepest, seeth the amiable and admirable secrets of the law, wherein I assure you the sages of the law in former times have had the deepest reach. And as the bucket in the depth is easily drawn to the uppermost part of the water, (for _nullum elementum in suo proprio loco est grave_), but take it from the water it cannot be drawn up but with a great difficulty; so, albeit beginnings of this study seem difficult, yet when the professor of the law can dive into the depth, it is delightful, easy, and without any heavy burden, so long as he keep himself in his own proper element[79].” Shakespear with much wit ridicules this disposition to simile-making, by putting in the mouth of a weak man a resemblance much of a piece with that now mentioned.