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.

PROP. XXXIII. 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 (III. Deff. i., ii.), but
it must be defined by the power, that is (III. vii.), 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 (III. lvi.), and
that men may be differently affected by one and the same
object (III. li.), 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.

PROP. XXXIV. 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 (III. xvi.), or because Peter has sole
possession of a thing which Paul also loves (III. xxxii. and
note), or for other causes (of which the chief are enumerated in
III. lv. note); it may therefore happen that Paul should hate
Peter (Def. of Emotions, vii.), consequently it may easily happen
also, that Peter should hate Paul in return, and that each should
endeavour to do the other an injury, (III. xxxix.), that is (IV.
xxx.), that they should be contrary one to another. But the
emotion of pain is always a passion or passive state (III. lix.);
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 Pete