Proposition 29. No individual thing, which is entirely different from our own nature, can help or check our power of activity, and absolutely nothing can do us good or harm, unless it has something in common with our nature. Proof: The power of every individual thing, and consequently the power of man, whereby he exists and operates, can only be determined by an individual thing (1.28), whose nature (2.6.) must be understood through the same nature as that, through which human nature is conceived.
Therefore our power of activity, however it be conceived, can be determined and consequently helped or hindered by the power of any other individual thing, which has something in common with us, but not by the power of anything, of which the nature is entirely different from our own; and since we call good or evil that which is the cause of pleasure or pain (4.8.), that is (3.11. note), which increases or diminishes, helps or hinders, our power of activity;
therefore, that which is entirely different from our nature can neither be to us good nor bad. Q.E.D.
Proposition 30. A thing cannot be bad for us through the quality which it has in common with our nature, but it is bad for us in so far as it is contrary to our nature. Proof: We call a thing bad when it is the cause of pain (4.8.), that is (by the Def., which see in 3.11 note), when it reduces or checks our power of action.
Therefore, if anything were bad for us through that quality which it has in common with our nature, it would be able itself to diminish or check that which it has in common with our nature, which (3.4) is absurd.
Wherefore nothing can be bad for us through that quality which it has in common with us, but, on the other hand, in so far as it is bad for us, that is (as we have just shown), in so far as it can diminish or check our power of action, it is contrary to our nature. Q.E.D.
Proposition 31. In so far as a thing is in harmony with our nature, it is necessarily good. Proof: In so far as a thing is in harmony with our nature, it cannot be bad for it.
It will therefore necessarily be either good or indifferent.
If it be assumed that it be neither good nor bad, nothing will follow from its nature (4. Def. 1), which tends to the preservation of our nature, that is (by the hypothesis), which tends to the preservation of the thing itself.
But this (3.6.) is absurd.
Therefore, in so far as a thing is in harmony with our nature, it is necessarily good. Q.E.D.
Corollary: It follows, that, in proportion as a thing is in harmony with our nature, so is it more useful or better for us, and vice versâ, in proportion as a thing is more useful for us, so is it more in harmony with our nature.
For, in so far as it is not in harmony with our nature, it will necessarily be different therefrom or contrary thereto.
If different, it can neither be good nor bad (4.29.).
if contrary, it will be contrary to that which is in harmony with our nature, that is, contrary to what is good—in short, bad.
Nothing, therefore, can be good, except in so far as it is in harmony with our nature;
and hence a thing is useful, in proportion as it is in harmony with our nature, and vice versâ. Q.E.D.
Proposition 32. In so far as men are a prey to passion, they cannot, in that respect, be said to be naturally in harmony. Proof: Things, which are said to be in harmony naturally, are understood to agree in power (3.7.), not in want of power or negation, and consequently not in passion (3.3. note); wherefore men, in so far as they are a prey to their passions, cannot be said to be naturally in harmony. Q.E.D. Note: This is also self-evident.
For, if we say that white and black only agree in the fact that neither is red, we absolutely affirm that the do not agree in any respect.
So, if we say that a man and a stone only agree in the fact that both are finite—wanting in power, not existing by the necessity of their own nature, or, lastly, indefinitely surpassed by the power of external causes—we should certainly affirm that a man and a stone are in no respect alike;
therefore, things which agree only in negation, or in qualities which neither possess, really agree in no respect.
Proposition 33. Men can differ in nature, in so far as they are assailed by those emotions, which are passions, or passive states; and to this extent one and the same man is variable and inconstant. Proof: The nature or essence of the emotions cannot be explained solely through our essence or nature (3. Def. 1., 2.), but it must be defined by the power, that is (3.7.), by the nature of external causes in comparison with our own;
hence it follows, that there are as many kinds of each emotion as there are external objects whereby we are affected (3.41), and that men may be differently affected by one and the same object (3.51.), and to this extent differ in nature.
Lastly, that one and the same man may be differently affected towards the same object, and may therefore be variable and inconstant. Q.E.D.
Proposition 34. In so far as men are assailed by emotions which are passions, they can be contrary one to another. Proof: A man, for instance Peter, can be the cause of Paul's feeling pain, because he (Peter) possesses something similar to that which Paul hates (3.16), or because Peter has sole possession of a thing which Paul also loves (3.32. and note), or for other causes (of which the chief are enumerated in 3.55. note).
It may therefore happen that Paul should hate Peter (Def. of Emotions, 7), consequently it may easily happen also, that Peter should hate Paul in return, and that each should endeavour to do the other an injury, (3.39), that is (4.30), that they should be contrary one to another.
But the emotion of pain is always a passion or passive state (3.59)
Hence men, in so far as they are assailed by emotions which are passions, can be contrary one to another. Q.E.D.
Note: I said that Paul may hate Peter, because he conceives that Peter possesses something which he (Paul) also loves;
from this it seems, at first sight, to follow, that these two men, through both loving the same thing, and, consequently, through agreement of their respective natures, stand in one another's way;
If this were so, Props. 30 and 31 of this part would be untrue.
But if we give the matter our unbiased attention, we shall see that the discrepancy vanishes. For the two men are not in one another's way in virtue of the agreement of their natures, that is, through both loving the same thing, but in virtue of one differing from the other.
For, in so far as each loves the same thing, the love of each is fostered thereby (3.31.), that is (Def. of the Emotions, vi.) the pleasure of each is fostered thereby.
Wherefore it is far from being the case, that they are at variance through both loving the same thing, and through the agreement in their natures.
The cause for their opposition lies, as I have said, solely in the fact that they are assumed to differ.
For we assume that Peter has the idea of the loved object as already in his possession, while Paul has the idea of the loved object as lost. Hence the one man will be affected with pleasure, the other will be affected with pain, and thus they will be at variance one with another. We can easily show in like manner, that all other causes of hatred depend solely on differences, and not on the agreement between men's natures.
Proposition 35. In so far only as men live in obedience to reason, do they always necessarily agree in nature. Proof: In so far as men are assailed by emotions that are passions, they can be different in nature (4.33.), and at variance one with another.
But men are only said to be active, in so far as they act in obedience to reason (3.3.).
Therefore, what so ever follows from human nature in so far as it is defined by reason must (3. Def. 2) be understood solely through human nature as its proximate cause.
But, since every man by the laws of his nature desires that which he deems good, and endeavours to remove that which he deems bad (4.19) and further, since that which we, in accordance with reason, deem good or bad, necessarily is good or bad (2.41).
It follows that men, in so far as they live in obedience to reason, necessarily do only such things as are necessarily good for human nature, and consequently for each individual man (4.31. Coroll.).
In other words, such things as are in harmony with each man's nature.
Therefore, men in so far as they live in obedience to reason, necessarily live always in harmony one with another. Q.E.D.
Corollary 1: There is no individual thing in nature, which is more useful to man, than a man who lives in obedience to reason.
For that thing is to man most useful, which is most in harmony with his nature (4.31. Coroll.).
That is, obviously, man.
But man acts absolutely according to the laws of his nature, when he lives in obedience to reason (3. Def. 2), and to this extent only is always necessarily in harmony with the nature of another man (by the last Prop.).
Wherefore among individual things nothing is more useful to man, than a man who lives in obedience to reason. Q.E.D.
Corollary 2: As every man seeks most that which is useful to him, so are men most useful one to another.
For the more a man seeks what is useful to him and endeavours to preserve himself, the more is he endowed with virtue (4.20.), or, what is the same thing (4. Def. 8), the more is he endowed with power to act according to the laws of his own nature, that is to live in obedience to reason.
But men are most in natural harmony, when they live in obedience to reason (by the last Prop.).
Therefore (by the foregoing Coroll.) men will be most useful one to another, when each seeks most that which is useful to him. Q.E.D.
Note: What we have just shown is attested by experience so conspicuously, that it is in the mouth of nearly everyone: "Man is to man a God."
Yet it rarely happens that men live in obedience to reason, for things are so ordered among them, that they are generally envious and troublesome one to another.
Nevertheless they are scarcely able to lead a solitary life, so that the definition of man as a social animal has met with general assent; in fact, men do derive from social life much more convenience than injury.
Let satirists then laugh their fill at human affairs, let theologians rail, and let misanthropes praise to their utmost the life of untutored rusticity, let them heap contempt on men and praises on beasts.
When all is said, they will find that men can provide for their wants much more easily by mutual help, and that only by uniting their forces can they escape from the dangers that on every side beset them:
not to say how much more excellent and worthy of our knowledge it is, to study the actions of men than the actions of beasts.
But I will treat of this more at length elsewhere.
Proposition 36. The highest good of those who follow virtue is common to all, and therefore all can equally rejoice therein. Proof: To act virtuously is to act in obedience with reason (4.24.), and whatsoever we endeavour to do in obedience to reason is to understand (4.26.). Therefore (4.28.) the highest good for those who follow after virtue is to know God; that is (2.47. and note) a good which is common to all and can be possessed by all men equally, in so far as they are of the same nature. Q.E.D. Note: Someone may ask how it would be, if the highest good of those who follow after virtue were not common to all?
Would it not then follow, as above (4.34), that men living in obedience to reason, that is (4.35), men in so far as they agree in nature, would be at variance one with another?
To such an inquiry, I make answer, that it follows not accidentally but from the very nature of reason, that main's highest good is common to all, inasmuch as it is deduced from the very essence of man, in so far as defined by reason; and that a man could neither be, nor be conceived without the power of taking pleasure in this highest good.
For it belongs to the essence of the human mind (II. xlvii.), to have an adequate knowledge of the eternal and infinite essence of God.
Proposition 37. The good which every man, who follows after virtue, desires for himself he will also desire for other men, and so much the more, in proportion as he has a greater knowledge of God. Proof: Men, in so far as they live in obedience to reason, are most useful to their fellow men (4.35; Coroll. 1).
Therefore (4.19.), we shall in obedience to reason necessarily endeavour to bring about that men should live in obedience to reason.
But the good which every man, in so far as he is guided by reason, or, in other words, follows after virtue, desires for himself, is to understand (4.26).
Wherefore the good, which each follower of virtue seeks for himself, he will desire also for others.
Again, desire, in so far as it is referred to the mind, is the very essence of the mind (Def. of the Emotions, 1).
The essence of the mind consists in knowledge (2.11), which involves the knowledge of God (2.47), and without it (1.15), can neither be, nor be conceived.
Therefore, in proportion as the mind's essence involves a greater knowledge of God, so also will be greater the desire of the follower of virtue, that other men should possess that which he seeks as good for himself. Q.E.D.
Another Proof: The good, which a man desires for himself and loves, he will love more constantly, if he sees that others love it also (3.31).
He will therefore endeavour that others should love it also; and as the good in question is common to all, and therefore all can rejoice therein, he will endeavour, for the same reason, to bring about that all should rejoice therein.
This he will do the more (3.37), in proportion as his own enjoyment of the good is greater.
Note 1: He who, guided by emotion only, endeavours to cause others to love what he loves himself, and to make the rest of the world live according to his own fancy, acts solely by impulse, and is, therefore, hateful, especially, to those who take delight in something different, and accordingly study and, by similar impulse, endeavour, to make men live in accordance with what pleases themselves.
Again, as the highest good sought by men under the guidance of emotion is often such, that it can only be possessed by a single individual, it follows that those who love it are not consistent in their intentions, but, while they delight to sing its praises, fear to be believed.
But he, who endeavours to lead men by reason, does not act by impulse but courteously and kindly, and his intention is always consistent.
Again, whatsoever we desire and do, whereof we are the cause in so far as we possess the idea of God, or know God, I set down to Religion.
The desire of well-doing, which is engendered by a life according to reason, I call piety.
Further, the desire, whereby a man living according to reason is bound to associate others with himself in friendship, I call honour;
by honourable I mean that which is praised by men living according to reason, and by base I mean that which is repugnant to the gaining of friendship.
I have also shown in addition what are the foundations of a state; and the difference between true virtue and infirmity may be readily gathered from what I have said; namely, that true virtue is nothing else but living in accordance with reason; while infirmity is nothing else but man's allowing himself to be led by things which are external to himself, and to be by them determined to act in a manner demanded by the general disposition of things rather than by his own nature considered solely in itself.
Such are the matters which I engaged to prove in Prop. 18. of this Part, whereby it is plain that the law against the slaughtering of animals is founded rather on vain superstition and womanish pity than on sound reason.
The rational quest of what is useful to us further teaches us the necessity of associating ourselves with our fellow men, but not with beasts, or things, whose nature is different from our own; we have the same rights in respect to them as they have in respect to us.
Nay, as everyone's right is defined by his virtue, or power, men have far greater rights over beasts than beasts have over men.
Still I do not deny that beasts feel:
what I deny is, that we may not consult our own advantage and use them as we please, treating them in the way which best suits us; for their nature is not like ours, and their emotions are naturally different from human emotions (3.57. note).
It remains for me to explain what I mean by just and unjust, sin and merit.
On these points see the following note.
Note 2: In the Appendix to Part 1, I undertook to explain praise and blame, merit and sin, justice and injustice.
Concerning praise and blame I have spoken in 3.29. note.
The time has now come to treat of the remaining terms.
But I must first say a few words concerning man in the state of nature and in society.
Every man exists by sovereign natural right.
Consequently, by sovereign natural right performs those actions which follow from the necessity of his own nature.
Therefore by sovereign natural right every man judges what is good and what is bad, takes care of his own advantage according to his own disposition (4.19. and 4.20), avenges the wrongs done to him (3.40 Coroll. 2), and endeavours to preserve that which he loves and to destroy that which he hates (3.28).
Now, if men lived under the guidance of reason, everyone would remain in possession of this his right, without any injury being done to his neighbour (4.35. Coroll. 1).
But seeing that they are a prey to their emotions, which far surpass human power or virtue (4.6), they are often drawn in different directions, and being at variance one with another (4.33, 4.34), stand in need of mutual help (4.35. note).
Wherefore, in order that men may live together in harmony, and may aid one another, it is necessary that they should forego their natural right, and, for the sake of security, refrain from all actions which can injure their fellow-men.
The way in which this end can be obtained, so that men who are necessarily a prey to their emotions (4.4. Coroll.), inconstant, and diverse, should be able to render each other mutually secure, and feel mutual trust, is evident from 4.7. and 3.39.
It is there shown, that an emotion can only be restrained by an emotion stronger than, and contrary to itself, and that men avoid inflicting injury through fear of incurring a greater injury themselves.
On this law society can be established, so long as it keeps in its own hand the right, possessed by everyone, of avenging injury, and pronouncing on good and evil;
and provided it also possesses the power to lay down a general rule of conduct, and to pass laws sanctioned, not by reason, which is powerless in restraining emotion, but by threats (4.17. note).
Such a society established with laws and the power of preserving itself is called a State, while those who live under its protection are called citizens.
We may readily understand that there is in the state of nature nothing, which by universal consent is pronounced good or bad; for in the state of nature everyone thinks solely of his own advantage, and
According to his disposition, with reference only to his individual advantage, decides what is good or bad, being bound by no law to anyone besides himself.
In the state of nature, therefore, sin is inconceivable; it can only exist in a state, where good and evil are pronounced on by common consent, and where everyone is bound to obey the State authority.
Sin, then, is nothing else but disobedience, which is therefore punished by the right of the State only.
Obedience, on the other hand, is set down as merit, inasmuch as a man is thought worthy of merit, if he takes delight in the advantages which a State provides.
Again, in the state of nature, no one is by common consent master of anything, nor is there anything in nature, which can be said to belong to one man rather than another:
all things are common to all. Hence, in the state of nature, we can conceive no wish to render to every man his own, or to deprive a man of that which belongs to him; in other words, there is nothing in the state of nature answering to justice and injustice.
Such ideas are only possible in a social state, when it is decreed by common consent what belongs to one man and what to another.
From all these considerations it is evident, that justice and injustice, sin and merit, are extrinsic ideas, and not attributes which display the nature of the mind.
But I have said enough.
Proposition 38. Whatsoever disposes the human body, so as to render it capable of being affected in an increased number of ways, or of affecting external bodies in an increased number of ways, is useful to man; and is so, in proportion as the body is thereby rendered more capable of being affected or affecting other bodies in an increased number of ways;
Contrariwise, whatsoever renders the body less capable in this respect is hurtful to man.
Proof: Whatsoever thus increases the capabilities of the body increases also the mind's capability of perception (2.14).
Therefore, whatsoever thus disposes the body and thus renders it capable, is necessarily good or useful (4.26, 4.27) and is so in proportion to the extent to which it can render the body capable.
Contrariwise (2.14, 4.26. 4.27), it is hurtful, if it renders the body in this respect less capable. Q.E.D.
Proposition 39. Whatsoever brings about the preservation of the proportion of motion and rest, which the parts of the human body mutually possess, is good; contrariwise, whatsoever causes a change in such proportion is bad. Proof: The human body needs many other bodies for its preservation (2 Post. 4).
But that which constitutes the specific reality (forma) of a human body is, that its parts communicate their several motions one to another in a certain fixed proportion (Def. before Lemma 4 after 2.13).
Therefore, whatsoever brings about the preservation of the proportion between motion and rest, which the parts of the human body mutually possess, preserves the specific reality of the human body, and consequently renders the human body capable of being affected in many ways and of affecting external bodies in many ways; consequently it is good (by the last Prop.).
Again, whatsoever brings about a change in the aforesaid proportion causes the human body to assume another specific character, in other words (see Preface to this Part towards the end, though the point is indeed self-evident), to be destroyed, and consequently totally incapable of being affected in an increased numbers of ways;
Therefore it is bad. Q.E.D.
Note: The extent to which such causes can injure or be of service to the mind will be explained in Part 5.
But I would here remark that I consider that a body undergoes death, when the proportion of motion and rest which obtained mutually among its several parts is changed.
For I do not venture to deny that a human body, while keeping the circulation of the blood and other properties, wherein the life of a body is thought to consist, may none the less be changed into another nature totally different from its own.
There is no reason, which compels me to maintain that a body does not die, unless it becomes a corpse; nay, experience would seem to point to the opposite conclusion.
It sometimes happens, that a man undergoes such changes, that I should hardly call him the same.
As I have heard tell of a certain Spanish poet, who had been seized with sickness, and though he recovered therefrom yet remained so oblivious of his past life, that he would not believe the plays and tragedies he had written to be his own: indeed, he might have been taken for a grown—up child, if he had also forgotten his native tongue. If this instance seems incredible, what shall we say of infants?
A man of ripe age deems their nature so unlike his own, that he can only be persuaded that he too has been an infant by the analogy of other men.
However, I prefer to leave such questions undiscussed, lest I should give ground to the superstitious for raising new issues.
Proposition 40. Whatsoever conduces to man's social life, or causes men to live together in harmony, is useful, whereas whatsoever brings discord into a State is bad. Proof: For whatsoever causes men to live together in harmony also causes them to live according to reason (4.35), and is therefore (4.26, 4.27) good, and (for the same reason) whatsoever brings about discord is bad. Q.E.D.