John Locke

“ The uneasiness a man finds in himself upon the absence of anything whose present enjoyment carries the idea of delight with it, is that we call desire ; which is greater or less, as that uneasiness is more or less vehement. Where, by the by, it may perhaps be of some use to remark, that the chief, if not only spur to human industry and action is uneasiness. For whatsoever good is proposed, if its absence carries no displeasure or pain with it, if a man be easy and content without it, there is no desire of it, nor endeavour after it ”

“ Things then are good or evil, only in reference to pleasure or pain. That we call good, which is apt to cause or increase pleasure, or diminish pain in us ; or else to procure or preserve us the possession of any other good or absence of any evil. And, on the contrary, we name that evil which is apt to produce or increase any pain, or diminish any pleasure in us : or else to procure us any evil, or deprive us of any good. By pleasure and pain, I must be understood to mean of body or mind, as they are commonly distinguished ”

“ Thus the being and welfare of a man’s children or friends, producing constant delight in him, he is said constantly to love them. But it suffices to note, that our ideas of love and hatred are but the dispositions of the mind, in respect of pleasure and pain in general, however caused in us. ”

“ For, to define them by the presence of good or evil, is no otherwise to make them known to us than by making us reflect on what we feel in ourselves, upon the several and various operations of good and evil upon our minds, as they are differently applied to or considered by us. ”

“ The passions too have most of them, in most persons, operations on the body, and cause various changes in it ; which not being always sensible, do not make a necessary part of the idea of each passion. For shame, which is an uneasiness of the mind upon the thought of having done something which is indecent, or will lessen the valued esteem which others have for us, has not always blushing accompanying it.
18. These instances to show how our ideas of the passions are got from sensation and reflection. I would not be mistaken here, as if I meant this as a Discourse of the Passions ”