Corollary.--Hence it follows, that man is necessarily always a prey to his passions, that he follows and obeys the general order of nature, and that he accommodates himself thereto, as much as the nature of things demands.
PROP. V. The power and increase of every passion, and its persistence in existing are not defined by the power, whereby we ourselves endeavour to persist in existing, but by the power of an external cause compared with our own.
Proof.--The essence of a passion cannot be explained through our essence alone (III. Deff. i. and ii.), that is (III. vii.), the power of a passion cannot be defined by the power, whereby we ourselves endeavour to persist in existing, but (as is shown in II. xvi.) must necessarily be defined by the power of an external cause compared with our own. Q.E.D.
PROP. VI. The force of any passion or emotion can overcome the rest of a man's activities or power, so that the emotion becomes obstinately fixed to him.
Proof.--The force and increase of any passion and its persistence in existing are defined by the power of an external cause compared with our own (by the foregoing Prop.); therefore (IV. iii.) it can overcome a man's power, &e. Q.E.D.
PROP. VII. An emotion can only be controlled or destroyed by another emotion contrary thereto, and with more power for controlling emotion.
Proof.--Emotion, in so far as it is referred to the mind, is an idea, whereby the mind affirms of its body a greater or less force of existence than before (cf. the general Definition of the Emotions at the end of Part III.). When, therefore, the mind is assailed by any emotion, the body is at the same time affected with a modification whereby its power of activity is increased or diminished. Now this modification of the body (IV. v.) receives from its cause the force for persistence in its being; which force can only be checked or destroyed by a bodily cause (II.
vi.), in virtue of the body being affected with a modification contrary to (III. v.) and stronger than itself (IV. Ax.); wherefore (II. xii.) the mind is affected by the idea of a modification contrary to, and stronger than the former modification, in other words, (by the general definition of the emotions) the mind will be affected by an emotion contrary to and stronger than the former emotion, which will exclude or destroy the existence of the former emotion; thus an emotion cannot be destroyed nor controlled except by a contrary and stronger emotion. Q.E.D.
Corollary.--An emotion, in so far as it is referred to the mind, can only be controlled or destroyed through an idea of a modification of the body contrary to, and stronger than, that which we are undergoing. For the emotion which we undergo can only be checked or destroyed by an emotion contrary to, and stronger than, itself, in other words, (by the general Definition of the Emotions) only by an idea of a modification of the body contrary to, and stronger than, the modification which we undergo.
PROP. VIII. The knowledge of good and evil is nothing else but the emotions of pleasure or pain, in so far as we are conscious thereof.
Proof.--We call a thing good or evil, when it is of service or the reverse in preserving our being (IV. Deff. i. and ii.), that is (III. vii.), when it increases or diminishes, helps or hinders, our power of activity. Thus, in so far as we perceive that a thing affects us with pleasure or pain, we call it good or evil; wherefore the knowledge of good and evil is nothing else but the idea of the pleasure or pain, which necessarily follows from that pleasurable or painful emotion (II. xxii.). But this idea is united to the emotion in the same way as mind is united to body (II. xxi.); that is, there is no real distinction between this idea and the emotion or idea of the modification of the body, save in conception only. Therefore the knowledge of good and evil is nothing else but the emotion, in so far as we are conscious thereof. Q.E.D.
PROP. IX. An emotion, whereof we conceive the cause to be with us at the present time, is stronger than if we did not conceive the cause to be with us.
Proof.--Imagination or conception is the idea, by which the mind regards a thing as present (II. xvii. note), but which indicates the disposition of the mind rather than the nature of the external thing (II. xvi. Coroll. ii.). An emotion is therefore a conception, in so far as it indicates the disposition of the body. But a conception (by II. xvii.) is stronger, so long as we conceive nothing which excludes the present existence of the external object; wherefore an emotion is also stronger or more intense, when we conceive the cause to be with us at the present time, than when we do not conceive the cause to be with us. Q.E.D.
Note.--When I said above in III. xviii. that we are affected by the image of what is past or future with the same emotion as if the thing conceived were present, I expressly stated, that this is only true in so far as we look solely to the image of the thing in question itself; for the thing's nature is unchanged, whether we have conceived it or not; I did not deny that the image becomes weaker, when we regard as present to us other things which exclude the present existence of the future object: I did not expressly call attention to the fact, because I purposed to treat of the strength of the emotions in this part of my work.
Corollary.--The image of something past or future, that is, of a thing which we regard as in relation to time past or time future, to the exclusion of time present, is, when other conditions are equal, weaker than the image of something present; consequently an emotion felt towards what is past or future is less intense, other conditions being equal, than an emotion felt towards something present.
PROP. X. Towards something future, which we conceive as close at hand, we are affected more intensely, than if we conceive that its time for existence is separated from the present by a longer interval; so too by the remembrance of what we conceive to have not long passed away we are affected more intensely, than if we conceive that it has long passed away.
Proof.--In so far as we conceive a thing as close at hand, or not long passed away, we conceive that which excludes the presence of the object less, than if its period of future existence were more distant from the present, or if it had long passed away (this is obvious) therefore (by the foregoing Prop.) we are, so far, more intensely affected towards it. Q.E.D.
Corollary.--From the remarks made in Def. vi. of this part it follows that, if objects are separated from the present by a longer period than we can define in conception, though their dates of occurrence be widely separated one from the other, they all affect us equally faintly.
PROP. XI. An emotion towards that which we conceive as necessary is, when other conditions are equal, more intense than an emotion towards that which possible, or contingent, or non--necessary.
Proof.--In so far as we conceive a thing to be necessary, we, to that extent, affirm its existence; on the other hand we deny a thing's existence, in so far as we conceive it not to be necessary (I. xxxiii. note. i.); wherefore (IV. ix.) an emotion towards that which is necessary is, other conditions being equal, more intense than an emotion that which is non--necessary. Q.E.D.
PROP. XII. An emotion towards a thing, which we know not to exist at the present time, and which we conceive as possible, is more intense, other conditions being equal, than an emotion towards a thing contingent.
Proof.--In so far as we conceive a thing as contingent, we are affected by the conception of some further thing, which would assert the existence of the former (IV. Def. iii.); but, on the other hand, we (by hypothesis) conceive certain things, which exclude its present existence. But, in so far as we conceive a thing to be possible in the future, we there by conceive things which assert its existence (IV. iv.), that is (III. xviii.), things which promote hope or fear: wherefore an emotion towards something possible is more vehement. Q.E.D.
Corollary.--An emotion towards a thing, which we know not to exist in the present, and which we conceive as contingent, is far fainter, than if we conceive the thing to be present with us.
Proof.--Emotion towards a thing, which we conceive to exist, is more intense than it would be, if we conceived the thing as future (IV. ix. Coroll.), and is much more vehement, than if the future time be conceived as far distant from the present (IV.
x.). Therefore an emotion towards a thing, whose period of existence we conceive to be far distant from the present, is far fainter, than if we conceive the thing as present; it is, nevertheless, more intense, than if we conceived the thing as contingent, wherefore an emotion towards a thing, which we regard as contingent, will be far fainter, than if we conceived the thing to be present with us. Q.E.D.
PROP. XIII. Emotion towards a thing contingent, which we know not to exist in the present, is, other conditions being equal, fainter than an emotion towards a thing past.
Proof.--In so far as we conceive a thing as contingent, we are not affected by the image of any other thing, which asserts the existence of the said thing (IV. Def. iii.), but, on the other hand (by hypothesis), we conceive certain things excluding its present existence. But, in so far as we conceive it in relation to time past, we are assumed to conceive something, which recalls the thing to memory, or excites the image thereof (II. xviii. and note), which is so far the same as regarding it as present (II.
xvii. Coroll.). Therefore (IV. ix.) an emotion towards a thing contingent, which we know does not exist in the present, is fainter, other conditions being equal, than an emotion towards a thing past. Q.E.D.
PROP. XIV. A true knowledge of good and evil cannot check any emotion by virtue of being true, but only in so far as it is considered as an emotion.
Proof.--An emotion is an idea, whereby the mind affirms of its body a greater or less force of existing than before (by the general Definition of the Emotions); therefore it has no positive quality, which can be destroyed by the presence of what is true; consequently the knowledge of good and evil cannot, by virtue of being true, restrain any emotion. But, in so far as such knowledge is an emotion (IV. viii.) if it have more strength for restraining emotion, it will to that extent be able to restrain the given emotion. Q.E.D.
PROP. XV. Desire arising from the knowledge of good and bad can be quenched or checked by many of the other desires arising from the emotions whereby we are assailed.
Proof.--From the true knowledge of good and evil, in so far as it is an emotion, necessarily arises desire (Def. of the Emotions, i.), the strength of which is proportioned to the strength of the emotion wherefrom it arises (III. xxxvii.). But, inasmuch as this desire arises (by hypothesis) from the fact of our truly understanding anything, it follows that it is also present with us, in so far as we are active (III. i.), and must therefore be understood through our essence only (III. Def. ii.); consequently (III. vii.) its force and increase can be defined solely by human power. Again, the desires arising from the emotions whereby we are assailed are stronger, in proportion as the said emotions are more vehement; wherefore their force and increase must be defined solely by the power of external causes, which, when compared with our own power, indefinitely surpass it (IV. iii.); hence the desires arising from like emotions may be more vehement, than the desire which arises from a true knowledge of good and evil, and may, consequently, control or quench it.
Q.E.D.
PROP. XVI. Desire arising from the knowledge of good and evil, in so far as such knowledge regards what is future, may be more easily controlled or quenched, than the desire for what is agreeable at the present moment.
Proof.--Emotion towards a thing, which we conceive as future, is fainter than emotion towards a thing that is present (IV. ix.
Coroll.). But desire, which arises from the true knowledge of good and evil, though it be concerned with things which are good at the moment, can be quenched or controlled by any headstrong desire (by the last Prop., the proof whereof is of universal application). Wherefore desire arising from such knowledge, when concerned with the future, can be more easily controlled or quenched, &c. Q.E.D.
PROP. XVII. Desire arising from the true knowledge of good and evil, in so far as such knowledge is concerned with what is contingent, can be controlled far more easily still, than desire for things that are present.
Proof.--This Prop. is proved in the same way as the last Prop.
from IV. xii. Coroll.
Note.--I think I have now shown the reason, why men are moved by opinion more readily than by true reason, why it is that the true knowledge of good and evil stirs up conflicts in the soul, and often yields to every kind of passion. This state of things gave rise to the exclamation of the poet:[12]---- "The better path I gaze at and approve, The worse--I follow."
[12] Ov. Met. vii.20, "Video meliora proboque, Deteriora sequor."
Ecclesiastes seems to have had the same thought in his mind, when he says, "He who increaseth knowledge increaseth sorrow." I have not written the above with the object of drawing the conclusion, that ignorance is more excellent than knowledge, or that a wise man is on a par with a fool in controlling his emotions, but because it is necessary to know the power and the infirmity of our nature, before we can determine what reason can do in restraining the emotions, and what is beyond her power. I have said, that in the present part I shall merely treat of human infirmity. The power of reason over the emotions I have settled to treat separately.
PROP. XVIII. Desire arising from pleasure is, other conditions being equal, stronger than desire arising from pain.
Proof.--Desire is the essence of a man (Def. of the Emotions, i.), that is, the endeavour whereby a man endeavours to persist in his own being. Wherefore desire arising from pleasure is, by the fact of pleasure being felt, increased or helped; on the contrary, desire arising from pain is, by the fact of pain being felt, diminished or hindered; hence the force of desire arising from pleasure must be defined by human power together with the power of an external cause, whereas desire arising from pain must be defined by human power only. Thus the former is the stronger of the two. Q.E.D.
Note.--In these few remarks I have explained the causes of human infirmity and inconstancy, and shown why men do not abide by the precepts of reason. It now remains for me to show what course is marked out for us by reason, which of the emotions are in harmony with the rules of human reason, and which of them are contrary thereto. But, before I begin to prove my Propositions in detailed geometrical fashion, it is advisable to sketch them briefly in advance, so that everyone may more readily grasp my meaning.
As reason makes no demands contrary to nature, it demands, that every man should love himself, should seek that which is useful to him--I mean, that which is really useful to him, should desire everything which really brings man to greater perfection, and should, each for himself, endeavour as far as he can to preserve his own being. This is as necessarily true, as that a whole is greater than its part. (Cf. III. iv.)
Again, as virtue is nothing else but action in accordance with the laws of one's own nature (IV. Def. viii.), and as no one endeavours to preserve his own being, except in accordance with the laws of his own nature, it follows, first, that the foundation of virtue is the endeavour to preserve one's own being, and that happiness consists in man's power of preserving his own being; secondly, that virtue is to be desired for its own sake, and that there is nothing more excellent or more useful to us, for the sake of which we should desire it; thirdly and lastly, that suicides are weak--minded, and are overcome by external causes repugnant to their nature. Further, it follows from Postulate iv., Part II., that we can never arrive at doing without all external things for the preservation of our being or living, so as to have no relations with things which are outside ourselves. Again, if we consider our mind, we see that our intellect would be more imperfect, if mind were alone, and could understand nothing besides itself. There are, then, many things outside ourselves, which are useful to us, and are, therefore, to be desired. Of such none can be discerned more excellent, than those which are in entire agreement with our nature. For if, for example, two individuals of entirely the same nature are united, they form a combination twice as powerful as either of them singly.
Therefore, to man there is nothing more useful than man--nothing, I repeat, more excellent for preserving their being can be wished for by men, than that all should so in all points agree, that the minds and bodies of all should form, as it were, one single mind and one single body, and that all should, with one consent, as far as they are able, endeavour to preserve their being, and all with one consent seek what is useful to them all.
Hence, men who are governed by reason--that is, who seek what is useful to them in accordance with reason, desire for themselves nothing, which they do not also desire for the rest of mankind, and, consequently, are just, faithful, and honourable in their conduct.
Such are the dictates of reason, which I purposed thus briefly to indicate, before beginning to prove them in greater detail. I have taken this course, in order, if possible, to gain the attention of those who believe, that the principle that every man is bound to seek what is useful for himself is the foundation of impiety, rather than of piety and virtue.
Therefore, after briefly showing that the contrary is the case, I go on to prove it by the same method, as that whereby I have hitherto proceeded.
PROP. XIX. Every man, by the laws of his nature, necessarily desires or shrinks from that which he deems to be good or bad.
Proof.--The knowledge of good and evil is (IV. viii.) the emotion of pleasure or pain, in so far as we are conscious thereof; therefore, every man necessarily desires what he thinks good, and shrinks from what he thinks bad. Now this appetite is nothing else but man's nature or essence (Cf. the Definition of Appetite, III. ix. note, and Def. of the Emotions, i.).