I. "Desire" is the actual essence of man, in so far as it is conceived, as determined to a particular activity by some given modification of itself.
^^^^^Explanation--We have said above, in the note to Prop. ix. of this part, that desire is appetite, with consciousness thereof; further, that appetite is the essence of man, in so far as it is determined to act in a way tending to promote its own persistence. But, in the same note, I also remarked that, strictly speaking, I recognize no distinction between appetite and desire. For whether a man be conscious of his appetite or not, it remains one and the same appetite. Thus, in order to avoid the appearance of tautology, I have refrained from explaining desire by appetite; but I have take care to define it in such a manner, as to comprehend, under one head, all those endeavours of human nature, which we distinguish by the terms appetite, will, desire, or impulse. I might, indeed, have said, that desire is the essence of man, in so far as it is conceived as determined to a particular activity; but from such a definition (cf. II. xxiii.) it would not follow that the mind can be conscious of its desire or appetite. Therefore, in order to imply the cause of such consciousness, it was necessary to add, "in so far as it is determined by some given modification," &c. For, by a modification of man's essence, we understand every disposition of the said essence, whether such disposition be innate, or whether it be conceived solely under the attribute of thought, or solely under the attribute of extension, or whether, lastly, it be referred simultaneously to both these attributes. By the term desire, then, I here mean all man's endeavours, impulses, appetites, and volitions, which vary according to each man's disposition, and are, therefore, not seldom opposed one to another, according as a man is drawn in different directions, and knows not where to turn.
II. "Pleasure" is the transition of a man from a less to a greater perfection.
III. "Pain" is the transition of a man from a greater to a less perfection.
^^^^^Explanation--I say transition: for pleasure is not perfection itself. For, if man were born with the perfection to which he passes, he would possess the same, without the emotion of pleasure. This appears more clearly from the consideration of the contrary emotion, pain. No one can deny, that pain consists in the transition to a less perfection, and not in the less perfection itself: for a man cannot be pained, in so far as he partakes of perfection of any degree.
Neither can we say, that pain consists in the absence of a greater perfection. For absence is nothing, whereas the emotion of pain is an activity; wherefore this activity can only be the activity of transition from a greater to a less perfection--in other words, it is an activity whereby a man's power of action is lessened or constrained (cf. III. xi. note).
I pass over the definitions of merriment, stimulation, melancholy, and grief, because these terms are generally used in reference to the body, and are merely kinds of pleasure or pain.
IV. "Wonder" is the conception (imaginatio) of anything, wherein the mind comes to a stand, because the particular concept in question has no connection with other concepts (cf. III. lii. and note).
^^^^^Explanation--In the note to II. xviii. we showed the reason, why the mind, from the contemplation of one thing, straightway falls to the contemplation of another thing, namely, because the images of the two things are so associated and arranged, that one follows the other. This state of association is impossible, if the image of the thing be new; the mind will then be at a stand in the contemplation thereof, until it is determined by other causes to think of something else.
Thus the conception of a new object, considered in itself, is of the same nature as other conceptions; hence, I do not include wonder among the emotions, nor do I see why I should so include it, inasmuch as this distraction of the mind arises from no positive cause drawing away the mind from other objects, but merely from the absence of a cause, which should determine the mind to pass from the contemplation of one object to the contemplation of another.
I, therefore, recognize only three primitive or primary emotions (as I said in the note to III. xi.), namely, pleasure, pain, and desire. I have spoken of wonder simply because it is customary to speak of certain emotions springing from the three primitive ones by different names, when they are referred to the objects of our wonder. I am led by the same motive to add a definition of contempt.
V. "Contempt" is the conception of anything which touches the mind so little, that its presence leads the mind to imagine those qualities which are not in it rather than such as are in it (cf. III. lii. note).
The definitions of veneration and scorn I here pass over, for I am not aware that any emotions are named after them.
VI. "Love" is pleasure, accompanied by the idea of an external cause.
