Most writers on the emotions and on human conduct seem
to be treating rather of matters outside nature than of natural
phenomena following nature's general laws. They appear to
conceive man to be situated in nature as a kingdom within a
kingdom: for they believe that he disturbs rather than follows
nature's order, that he has absolute control over his actions,
and that he is determined solely by himself. They attribute
human infirmities and fickleness, not to the power of nature
in general, but to some mysterious flaw in the nature of man,
which accordingly they bemoan, deride, despise, or, as
usually happens, abuse: he, who succeeds in hitting off
the weakness of the human mind more eloquently or more
acutely than his fellows, is looked upon as a seer. Still there
has been no lack of very excellent men (to whose toil and
industry I confess myself much indebted), who have written
many noteworthy things concerning the right way of life,
and have given much sage advice to mankind. But no one,
so far as I know, has defined the nature and strength of the
emotions, and the power of the mind against them for their
restraint.
I do not forget, that the illustrious Descartes, though he
believed, that the mind has absolute power over its actions,
strove to explain human emotions by their primary causes,
and, at the same time, to point out a way, by which the mind
might attain to absolute dominion over them. However,
in my opinion, he accomplishes nothing beyond a display
of the acuteness of his own great intellect, as I will show
in the proper place. For the present I wish to revert to
those, who would rather abuse or deride human emotions
than understand them. Such persons will, doubtless think
it strange that I should attempt to treat of human vice and
folly geometrically, and should wish to set forth with rigid
reasoning those matters which they cry out against as
repugnant to reason, frivolous, absurd, and dreadful.
However, such is my plan. Nothing comes to pass in nature,
which can be set down to a flaw therein; for nature is always
the same, and everywhere one and the same in her efficacy
and power of action; that is, nature's laws and ordinances,
whereby all things come to pass and change from one form
to another, are everywhere and always the same; so that
there should be one and the same method of understanding
the nature of all things whatsoever, namely, through nature's
universal laws and rules. Thus the passions of hatred, anger,
envy, and so on, considered in themselves, follow from this
same necessity and efficacy of nature; they answer to certain
definite causes, through which they are understood, and
possess certain properties as worthy of being known as
the properties of anything else, whereof the contemplation
in itself affords us delight. I shall, therefore, treat of the
nature and strength of the emotions according to the same
method, as I employed heretofore in my investigations
concerning God and the mind. I shall consider human
actions and desires in exactly the same manner, as though
I were concerned with lines, planes, and solids.