It is now some years since I
detected how many were the false beliefs that I
had from my earliest youth admitted as true, and
how doubtful was everything I had since
constructed on this basis; and from that time I
was convinced that I must once for all seriously
undertake to rid myself of all the opinions which
I had formerly accepted, and commence to build
anew from the foundation, if I wanted to
establish any firm and permanent structure in the
sciences. But as this
enterprise appeared to be a very great one, I
waited until I had attained an age so mature that
I could not hope that at any later date I should
be better fitted to execute my design. This
reason caused me to delay so long that I should feel
that I was doing wrong were I to occupy in
deliberation the time that yet remains to me for
action. To-day, then, since
very opportunely for the plan I have in view I
have delivered my mind from every care [and am
happily agitated by no passions] and since I have
procured for myself an assured leisure in a
peaceable retirement, I shall at last seriously
and freely address myself to the general upheaval
of all my former opinions. (Note 1)
Now for this object it
is not necessary that I should show that all of
these are false -- I shall perhaps never arrive at
this end. But inasmuch as reason already persuades
me that I ought no less carefully to withhold my
assent from matters which are not entirely certain
and indubitable than from those which appear to me
manifestly to be false, if I am able to find in each
one some reason to doubt, this will suffice to
justify my rejecting the whole. And for that end it
will not be requisite that I should examine each in
particular, which would be an endless undertaking;
for owing to the fact that the destruction of the
foundations of necessity brings with it the downfall
of the rest of the edifice, I
shall only in the first place attack those
principles upon which all my former opinions
rested. (Note 2)
All
that up to the present time I have accepted as
most true and certain I have learned either from
the senses or through the senses; but it is
sometimes proved to me that these senses are
deceptive, and it is wiser not to trust entirely
to anything by which we have once been deceived.
(Note 3)
But it may be that
although the senses sometimes deceive us concerning
things which are hardly perceptible, or very far
away, there are yet many others to be met with as to
which we cannot reasonably have any doubt, although
we recognise them by their means. For example, there
is the fact that I am here, seated by the fire,
attired in a dressing gown, having this paper in my
hands and other similar matters. And how could I
deny that these hands and this body are mine, were
it not perhaps that I compare myself to certain
persons, devoid of sense, whose cerebella are so
troubled and clouded by the violent vapours of black
bile, that they constantly assure us that they think
they are kings when they are really quite poor, or
that they are clothed in purple when they are really
without covering, or who imagine that they have an
earthenware head or are nothing but pumpkins or are
made of glass. But they are
mad, and I should not be any the less insane were
I to follow examples so extravagant. (Note
4)
At the same time I must remember that I am a man,
and that consequently I am in the habit of
sleeping, and in my dreams representing to myself
the same things or sometimes even less probable
things, than do those who are insane in their
waking moments. (Note 5)
How often has it happened to me that in the night I
dreamt that I found myself in this particular place,
that I was dressed and seated near the fire, whilst
in reality I was lying undressed in bed! At this
moment it does indeed seem to me that it is with
eyes awake that I am looking at this paper; that
this head which I move is not asleep, that it is
deliberately and of set purpose that I extend my
hand and perceive it; what happens in sleep does not
appear so clear nor so distinct as does all this.
But in thinking over this I remind myself that on
many occasions I have in sleep been deceived by
similar illusions, and in dwelling carefully on this
reflection I see so manifestly that there are no
certain indications by which we may clearly
distinguish wakefulness from sleep that I am lost in
astonishment. And my astonishment is such that it is
almost capable of persuading me that I now dream.
Now let us assume that
we are asleep and that all these particulars, e.g.
that we open our eyes, shake our head, extend our
hands, and so on, are but false delusions; and let
us reflect that possibly neither our hands nor our
whole body are such as they appear to us to be. At
the same time we must at least confess that the
things which are represented to us in sleep are like
painted representations which can only have been
formed as the counterparts of something real and
true, and that in this way those general things at
least, i.e. eyes, a head, hands, and a whole body,
are not imaginary things, but things really
existent. For, as a matter of fact, painters, even
when they study with the greatest skill to represent
sirens and satyrs by forms the most strange and
extraordinary, cannot give them natures which are
entirely new, but merely make a certain medley of
the members of different animals; or if their
imagination is extravagant enough to invent
something so novel that nothing similar has ever
before been seen, and that then their work
represents a thing purely fictitious and absolutely
false, it is certain all the same that the colours
of which this is composed are necessarily real. And
for the same reason, although these general things,
to wit, [a body], eyes, a head, hands, and such
like, may be imaginary, we are bound at the same
time to confess that there are at least some other
objects yet more simple and more universal, which
are real and true; and of these just in the same way
as with certain real colours, all these images of
things which dwell in our thoughts, whether true and
real or false and fantastic, are formed.
To such a class of
things pertains corporeal nature in general, and its
extension, the figure of extended things, their
quantity or magnitude and number, as also the place
in which they are, the time which measures their
duration, and so on.
That is possibly why our reasoning is not unjust when
we conclude from this that Physics, Astronomy,
Medicine and all other sciences which have as
their end the consideration of composite things,
are very dubious and uncertain; but that
Arithmetic, Geometry and other sciences of that
kind which only treat of things that are very
simple and very general, without taking great
trouble to ascertain whether they are actually
existent or not, contain some measure of certainty
and an element of the indubitable. For whether I
am awake or asleep, two and three together always
form five, and the square can never have more than
four sides, and it does not seem possible that
truths so clear and apparent can be suspected of
any falsity [or uncertainty]. (Note
6)
Nevertheless I have long had fixed in my mind
the belief that an all-powerful God existed by
whom I have been created such as I am. But how do
I know that He has not brought it to pass that
there is no earth, no heaven, no extended body, no
magnitude, no place, and that nevertheless [I
possess the perceptions of all these things and
that] they seem to me to exist just exactly as I
now see them? And, besides, as I sometimes imagine
that others deceive themselves in the things which
they think they know best, how do I know that I am
not deceived every time that I add two and three,
or count the sides of a square, or judge of things
yet simpler, if anything simpler can be imagined?
But possibly God has not desired that I should be
thus deceived, for He is said to be supremely good.
If, however, it is contrary to
His goodness to have made me such that I
constantly deceive myself, it would also appear to
be contrary to His goodness to permit me to be
sometimes deceived, and nevertheless I cannot
doubt that He does permit this. (Note
7)
There may indeed be
those who would prefer to deny the existence of a
God so powerful, rather than believe that all other
things are uncertain. But let us not oppose them for
the present, and grant that all that is here said of
a God is a fable; nevertheless in whatever way they
suppose that I have arrived at the state of being
that I have reached -- whether they attribute it to
fate or to accident, or make out that it is by a
continual succession of antecedents, or by some
other method -- since to err and deceive oneself is
a defect, it is clear that the greater will be the
probability of my being so imperfect as to deceive
myself ever, as is the Author to whom they assign my
origin the less powerful. To these reasons I have
certainly nothing to reply, but at the end I feel constrained to confess that
there is nothing in all that I formerly believed
to be true, of which I cannot in some measure
doubt, and that not merely through want of thought
or through levity, but for reasons which are very
powerful and maturely considered; so that
henceforth I ought not the less carefully to
refrain from giving credence to these opinions
than to that which is manifestly false, if I
desire to arrive at any certainty [in the
sciences]. (Note 8)
But
it is not sufficient to have made these remarks,
we must also be careful to keep them in mind. For
these ancient and commonly held opinions still
revert frequently to my mind, long and familiar
custom having given them the right to occupy my mind
against my inclination and rendered them almost
masters of my belief; nor will I ever lose the habit
of deferring to them or of placing my confidence in
them, so long as I consider them as they really are,
i.e. opinions in some measure doubtful, as I have
just shown, and at the same time highly probable, so
that there is much more reason to believe in than to
deny them. That is why I
consider that I shall not be acting amiss, if,
taking of set purpose a contrary belief, I allow
myself to be deceived, and for a certain time
pretend that all these opinions are entirely false
and imaginary, until at last, having thus balanced
my former prejudices with my latter [so that they
cannot divert my opinions more to one side than to
the other], my judgment will no longer be
dominated by bad usage or turned away from the
right knowledge of the truth. For I am assured
that there can be neither peril nor error in this
course, and that I cannot at present yield too
much to distrust, since I am not considering the
question of action, but only of knowledge. (Note
9)
I
shall then suppose, not that God who is supremely
good and the fountain of truth, but some evil
genius not less powerful than deceitful, has
employed his whole energies in deceiving me; I
shall consider that the heavens, the earth,
colours, figures, sound, and all other external
things are nought but the illusions and dreams of
which this genius has availed himself in order to
lay traps for my credulity; I shall consider
myself as having no hands, no eyes, no flesh, no
blood, nor any senses, yet falsely believing
myself to possess all these things; I shall remain
obstinately attached to this idea, and if by this
means it is not in my power to arrive at the
knowledge of any truth, I may at least do what is
in my power [i.e. suspend my judgment], and with
firm purpose avoid giving credence to any false
thing, or being imposed upon by this arch
deceiver, however powerful and deceptive he may
be. (Note 10)
But this task is a laborious one, and insensibly a
certain lassitude leads me into the course of my
ordinary life. And just as a captive who in sleep
enjoys an imaginary liberty, when he begins to
suspect that his liberty is but a dream, fears to
awaken, and conspires with these agreeable illusions
that the deception may be prolonged, so insensibly
of my own accord I fall back into my former
opinions, and I dread awakening from this slumber,
lest the laborious wakefulness which would follow
the tranquillity of this repose should have to be
spent not in daylight, but in the excessive darkness
of the difficulties which have just been discussed.
last update: Jun 19 2003