As joy has its opposite, sorrow, and love its opposite, hate, so also desire has its opposite, aversion; and the objects of aversion are as numerous as the objects of desire. The desire of wealth has its counterpart, the aversion to poverty and want; the desire of life and happiness stands over against the aversion to suffering and death. The two are so to speak, the positive and negative poles of feeling. _Hope and Fear._--There is yet another and important class of our emotions, having not a little to do with the happiness or misery of life, casting its lights and shadows over no small part of our little path from the cradle to the grave, our _hopes_ and our _fears_. These, however important in themselves, are, nevertheless, but modifications of the principles of desire and aversion, and are, therefore, to be referred to the same general division of the sensibilities. Hope is the desire of some expected good, fear the aversion to some anticipated evil. _Summary of Classes._--To the three comprehensive classes now named, _Simple Emotions_, _Affections_, and _Desires_ may be referred, if I mistake not, the various sensibilities of our nature; or, if the analysis and classification be not complete and exhaustive, it is at least sufficiently minute for our present purpose. HISTORICAL SKETCH OF THE LEADING DIVISIONS OF THE SENSIBILITIES ADOPTED BY DIFFERENT WRITERS. _Important to know the Principles of Division adopted by others._--The discussion of the present topic would be incomplete without a glance at the _history_ of the same. It is of service, having obtained some definite results and conclusions of our own, to know also what have been the views and conclusions of others upon the same matter. As with regard to the intellectual powers, so also with respect to the sensibilities, different principles of division and classification have been adopted by different writers. Our limits will allow us to glance only at the more important of these. _General Principles of Classification._--Of those who have written upon the sensibilities, some have placed them in contrast to each other, as hope and fear, love and hate, etc., making this the principle of division; others have classed them as personal, social, etc.; others as relating to time, the past, the present, and the future; others as instinctive and rational; while most who have had occasion to treat of this part of our mental constitution, have considered it with reference solely or mainly to the science of ethics or morals, and have adopted such a division and arrangement as best suited that end, without special regard to the psychology of the matter. _Of the Greek Schools._--Among the Greeks, the Academicians included the various emotions under the four principal ones, fear, desire, joy, and grief, classing despair and aversion under grief, while hope, courage, and anger were comprised under desire.