I believed that an attempt to range and methodize some of our most leading passions would be a good preparative to such an inquiry as we are going to make in the ensuing discourse. The passions I have mentioned are almost the only ones which it can be necessary to consider in our present design; though the variety of the passions is great, and worthy, in every branch of that variety, of an attentive investigation. The more accurately we search into the human mind, the stronger traces we everywhere find of His wisdom who made it. If a discourse on the use of the parts of the body may be considered as a hymn to the Creator; the use of the passions, which are the organs of the mind, cannot be barren of praise to him, nor unproductive to ourselves of that noble and uncommon union of science and admiration, which a contemplation of the works of infinite wisdom alone can afford to a rational mind; whilst, referring to him whatever we find of right or good or fair in ourselves, discovering his strength and wisdom even in our own weakness and imperfection, honoring them where we discover them clearly, and adoring their profundity where we are lost in our search, we may be inquisitive without impertinence, and elevated without pride; we may be admitted, if I may dare to say so, into the counsels of the Almighty by a consideration of his works. The elevation of the mind ought to be the principal end of all our studies; which, if they do not in some measure effect, they are of very little service to us. But, besides this great purpose, a consideration of the rationale of our passions seems to me very necessary for all who would affect them upon solid and sure principles. It is not enough to know them in general; to affect them after a delicate manner, or to judge properly of any work designed to affect them, we should know the exact boundaries of their several jurisdictions; we should pursue them through all their variety of operations, and pierce into the inmost, and what might appear inaccessible parts of our nature, Quod latet arcana non enarrabile fibra.