Meditations on First Philosophy
Philosophy 1
Spring, 2002
G. J. Mattey
The Religious Crisis
• The Protestant Reformation destroyed the
universal intellectual authority of the
Roman Catholic Church
• Individual conscience was offered as a
higher authority
• One philosophical issue was how to
adjudicate this dispute
• Another was what role reason should play
The Scientific Crisis
• Natural philosophers such as Galileo
challenged the Aristotelian account of the
natural world
• Mathematical explanations appeared
preferable to teleological explanations
• Hobbes’s account of the natural world
seemed to exclude any role for God
The Skeptical Crisis
• The writings of the ancient skeptics had
been recovered during the Renaissance
• Powerful skeptical arguments were
mobilized by philosophers such as
Montaigne
• These arguments threatened religious as
well as scientific belief
The Problem of the Criterion
• This problem was posed by ancient
Pyrrhonian skeptics
• How can a dispute (e.g., authority vs.
conscience) be settled?
• One may not appeal to what is in dispute
• So a new criterion is needed
• If the new criterion is in dispute, the
problem arises once again
René Descartes
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Born 1596
French
Studied under the Jesuits
Invented analytic
geometry
• Pursued many scientific
investigations
• “Father of modern
philosophy”
• Died 1650
Descartes’s Contributions
• Produced a comprehensive mathematical
system of the world, with “laws of nature”
such as inertia
• Looked for new first principles of
philosophy in pure reason
• Tried to refute skepticism decisively
• Attempted to prove that the mind an
autonomous being, distinct from the body
Preconceptions
• The Aristotelian account of knowledge
began with notions acquired from senseperception
• Descartes held that these “preconceptions”
acquired in youth are the source of error
• He sought to overturn the preconceptions of
his youth, thus purging his mind of error
The “Method of Doubt”
• Descartes sought a method of removing all
at once his erroneous opinions
• He would treat as false any opinion that was
open to the slightest doubt
• Once all dubious opinions were removed,
he would see what survived
• He would build on this foundation an
edifice of knowledge free of preconceptions
Doubts About Specific Objects
• My opinions about specific objects are based on
sense-perception
• Opinions about obscure objects (e.g., small or
distant ones) are dubious because I am often
deceived by our sensory input
• Opinions about near and familiar objects (e.g., “I
am seated next to the fireplace”) are dubious
because I have no criterion for distinguishing my
waking states from my dreaming states
Doubts About General Objects
• My mistaken opinions about specific objects
depend on my opinions about general objects (e.g.,
shapes)
• People make errors regarding even the simplest
things (e.g., that 2+3=5)
• I may have been made so that I can be deceived
even about them
– A powerful God could have brought it about that the
natural universe does not exist
– A lesser cause or chance could easily have brought it
about that I am defective
Sustaining Doubt
• The method of doubt requires that for now I treat
my opinions about sensed specific and rationally
known general objects as false
• A uniform way of keeping my doubts in mind is
by assuming that there is a powerful evil genius
who is exerting its will to deceive me
• Still, it is difficult to sustain this doubt due to
laziness
If I Am Thinking, I Exist
• Is there anything left that is not subject to doubt?
• Perhaps it is some specific object that is not
perceived through the senses
• Such an object is myself, since I must exist in
order to doubt at all (Augustine)
• In the period of time when I think (cogito) I am
something, an evil genius cannot bring it about
that I am nothing
I Am a Thinking Thing
• What is the I which, necessarily, exists
when it is thinking?
• It is a thinking thing (res cogitans)
• It need not have any bodily characteristics,
since it has been assumed that there are no
bodies and no knowledge of general things
• So what I am is not known by imagination,
which simulates shapes
What a Thinking Thing Does
• Most characteristics of a thinking thing are
conditions that allowed me to reject my former
opinions
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Doubting
Understanding
Affirming
Denying
Willing
Refusing
Imagining and Sensing
• The same thing that doubts, understands, etc. also:
– Imagines many things, even when not willing to do so
– Notices many things that appear to arise from the
senses
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It imagines things as if bodies exist
It “senses,” i.e., seems to see, hear, feel, etc.
I cannot doubt that these are powers in me
They can all be classified as “thinking”
Intellectual Perception
• Suppose that bodies exist: how could they be
known?
• The senses reveal nothing constant in them
• The imagination cannot comprehend their infinite
possible variations
• They are perceived only through inspection by the
intellect, which understands their constant
features: extension, flexibility, mutability
• The intellectual inspection that reveals the nature
of bodies even more clearly reveals the nature of
mind
Clear and Distinct Perception
• I now know a number of things about myself
• To know these things, I must know what it is for
me to know them
• The condition for knowledge is clarity and
distinctness in the perception of what I affirm
• It seems a general rule that whatever I perceive
very clearly and very distinctly is true
The Return of Doubt
• When I turn my attention to what I perceive very
clearly and distinctly, I believe that I cannot be
deceived about them
• But when I turn my attention to my preconceived
notion of God, I believe that I might have been
made so that I can be deceived about them
• To dispel this “very tenuous and, so to speak,
metaphysical” doubt, it must be determined
whether God exists and can be a deceiver
Truth and Falsity
• Truth and falsity reside in judgments
• Judgment embraces in thought something beyond
the subject judged
• The primary subjects of judgment are ideas
• Ideas in themselves are neither true nor false (nor
are acts of will)
• Error arises most commonly when the idea is
taken to be a likeness of something outside me
Grounds for Judgment
• Why do I take it that my ideas are likenesses of
things outside me?
– I seem to have been taught so by nature: I
spontaneously believe this
• Natural impulses can give rise to error
• But the “light of nature” always yields true judgments (e.g.,
“from the fact that I doubt, it follows that I am”)
– The ideas come to me against my will
• But they might be produced by something in me
• Even if the ideas come from things outside me, they might not
be likeness of them (e.g., the small image of the sun)
A Hierarchy of Ideas
• Ideas as modes of thought are equal: one idea is no
more an idea than another
• But they are not equal in the objects they
represent
• An idea of a substance has more “objective”
reality than that of an accident
• An idea of an infinite substance has more
objective reality than that of a finite substance
Cause and Effect
• We know by the light of nature that the
efficient cause of a thing has at least as
much reality as its effect
• This holds for objective reality as well as
the “formal” reality of existing things
• The cause of the objective reality of an idea
must have at least as much reality as it does:
it cannot get this reality from nothing
The Cause of Ideas
• There must be a formal reality which is the cause
of the objective reality of ideas
• This formal reality might be an idea itself
• But the causal chain cannot be infinite: there must
be a non-idea causing the first idea
• This is “a sort of archetype that contains formally
all the reality that is in the idea merely
objectively”
Escape from the Circle of Ideas?
• Suppose there is an idea in me whose
objective reality is so great that I cannot be
the formal reality that is its cause
• Then I am not alone in the world: the cause
of that idea exists as well
• Are there any ideas of this sort?
• Different classes of ideas will have to be
examined
Ideas of Finite Beings
• I could be the cause of ideas of other men,
animals or angels: they are like me
• And I could be the cause of ideas of
physical objects
– Their sensory qualities are very obscure, and
even if accurate, they are no more real than I
– Their greatest objective reality is as substances,
but I am a substance as well
The Idea of God
• God is an “infinite, independent, supremely
intelligent and supremely powerful” substance
who created me and all else
• The idea of God is not “materially false,” like that
of heat or cold, because of its clarity and
distinctness
• I do not have the degree of reality needed to
produce an idea of God
• There is much in me that is merely potential and
not actual
The Cause of Myself
• Since it is easy to be blinded by preconceptions, I
will ask whether I could exist without God
• I did not get my being from myself, since I would
have given myself all the perfections
• I have not always existed, since I need something
to sustain my existence over each moment of time,
and I cannot perpetuate my own existence
• I did not get my being from my parents, since they
could not be the ultimate source of my idea of God
The Existence of God
• The only way I can have an idea of God is
by God’s causing me to have the idea
• Since I and my idea exist, God exists
• The idea of God in my mind is like a
signature on a painting
• The idea I have of God precludes God’s
being a deceiver, since deception implies an
imperfection
The Possibility of Error
• God did not give me a faculty of judgment
that would lead me to error if I did not use it
properly
• So error is the result of my improper use of
my judgment
• This is possible because of my finitude, the
fact that I partake to some extent of nothing
The Cause of Error
• Why do I err, since it seems that it would be better
for me not to?
• I cannot know what is best based on what appears
to my mind
• Error is the result of my faculty of choosing overreaching my faculty of knowing
• Will is infinite, but my understanding is limited
• I resemble God most through the infinitude of my
will
Willing
• Willing is to be able to do or not to do the
same thing, e.g., to affirm or deny it
• A better account: willing is the mind’s
movement toward or away from what is
proposed by the intellect, in a way that we
sense we are determined by no external
force
Freedom of the Will
• Freedom is the inclination to choose the course
that appears to be good and true
• This inclination may be based on clear
understanding or an impulse implanted in me by
God
• In my judgment that I truly exist, “a great light
gave way to a great inclination of my will”
• Therefore, indifference is the lowest degree of
freedom, since the intellect sees no reason to
prefer one course to another
Using and Abusing Free Will
• The indifference of the will extends to that about
which we know nothing
• It even extends to what is probable
• My knowledge that it is not certain (e.g., whether I
have a body) pushes me away from judging it as
true
• This diffidence is a proper use of judgment
• But making an assertion or denial in such a case is
abuse of my free will
• If I am right, it is only through luck
No Complaints Against God
• The ability to err might be thought to be grounds
for complaint against God, but:
– I should thank God for my limited intellect, since God
owes me nothing
– My will must be unlimited (and hence subject to error)
because it is unitary
– Error is privation, and hence not a thing
– Even though God could have made me error-free, it was
for the best that I was made as I was
– I can still avoid error through self-restraint
So Do External Things Exist?
• Some remaining issues about the nature of
God and myself will be postponed
• The main question is whether the doubts
about the existence of external objects can
be overcome?
• The first step is to examine the ideas of
external things for clarity and distinctness
• This will reveal what they must be
Extension and Duration
• I have clear ideas of two continuous
quantities, extension and duration
• Shapes and positions are understood
through extension, and motion through
extension and duration
• They apply to true and immutable natures,
whether or not external objects exist
Knowledge of Natures
• Natures are not fabricated by me, as can be
seen through geometrical demonstrations
• I cannot refrain from assenting to judgments
about them while perceiving them clearly
• Even when my attention was on the senses,
I still regarded mathematical demonstration
as certain
Another Proof of God’s Existence
1. What I clearly and distinctly perceive to
belong to a thing really does
2. I clearly and distinctly perceive that God’s
nature is that of a supremely perfect being
3. It belongs to the nature of a supremely
perfect being to exist always
4. So, God always exists
A Sophism?
• We do not suppose that because a mountain
is inseparable from a valley, a mountain
exists: they may both fail to exist
• So it seems possible to think of all God’s
properties without God’s existing
• But to reason this way is fallacious: it is
existence itself that cannot be separated
from God’s nature as a perfect being
Knowing God’s Nature
• God’s nature, like that of a geometrical
object, is not fabricated by me
– God is the only being I can think of whose
essence includes its existence
– When I see that God now exists, I also
perceived clearly that God has existed eternally
– There are other features in God that I perceive
and cannot remove or change
The Most Certain Knowledge
• The main way in which we can tell that we
know God’s nature is through the clarity
and distinctness of the perception of it
• This is revealed even if it was obscured
initially by prejudice.
• Once it is known, nothing is more certain,
or known more easily than that God exists
Removing a Slight Doubt
• The remaining “tenuous” doubt was about
things which are no longer clearly perceived
• God is not a deceiver, so if I remember that
I had clearly perceived them, I can count on
my memory
• Errors in memory occur when the original
perception was not clear
• This holds even if I am always dreaming
Imagination
• It seems that it follows from my use of the
imagination that material objects exist
• Use of the imagination requires more
exertion than that of the pure intellect
• I could exist as a pure understanding even
without imagination
• So a probable conjecture is that imagination
depends on something else—a body
Sense
• Some things are better known through sense
than through the intellect
• These include colors, sounds, tastes, pains
• Can an argument for the existence of
material things be based on the
contributions of the mode of thinking called
“sense”?
• I must rehearse what caused doubt initially
Naïve Beliefs About Sense
• Bodies—my own and others—seem to be the
objects of sense
• Associated with my body are ideas of pain and
pleasure
• Many other ideas are also associated with bodies
• They come to me against my will, and so do not
seem to come from me
• “My body” seems particularly related to me
Doubts About Bodies
• There are numerous perceptual illusions, even
with respect to pain
• I have no reason to believe that ideas in my
dreams come from bodies, but I can dream
anything I think I receive from bodies
• I might be constituted by nature to be deceived
about what is true
• What is against my will could originate in me
Separating Mind from Body
• God can make me without a body
• So my essence consists entirely of my being
a thinking thing
• I am really distinct from my body
• Imagination and sense depend on my mind
as modes
• But I can exist without them
Bodies Exist
1. My passive faculty of sensing requires an active
faculty producing what is sensed
2. This faculty requires no act of understanding and
it operates against my will
3. So, the active faculty is not in me
4. So, the active faculty is in another substance:
God, a super-human spirit, or body
5. If it were not in body, God would be a deceiver
6. God is no deceiver
7. So, bodies exist
The Teachings of Nature
• Nature is the handiwork of God
• It teaches me about the relation of my mind and
my body
• I and my body form a single intermingled thing
• It also teaches me which other bodies should be
pursued or shunned
• Anything else belongs exclusively to mind or to
body
• Nature does not teach me that there is a likeness
between ideas and bodies
A Final Problem
• God, through nature, teaches me what to
avoid as harmful or pursue as useful
• I am sometimes mistaken in this, yet God is
no deceiver
• Attention to what is clear and distinct does
not solve the problem, because in matters of
utility, everything is obscure and confused
Natural Errors
• The mind is a simple thing, while the body
is a composite with many parts
• The interface of mind and body is in a
“common” sense in the brain
• What is communicated to the mind is the
last motion reaching the common sense
• But the motion from a remote part of the
body could be corrupted on the way
Coherence
• The final doubts have been dispelled
• A new argument against the dream
hypothesis is given
• One can notice a considerable difference
between waking and dreaming
• Waking life is connected without
interruption, while dreaming life is not