Revised, 1/7/07. René Descartes (1596-1650 AD). Meditations on First Philosophy (1641). (Text, pp. 283-306). Anthem. Background. Descartes’ Problem. The problem of skepticism (D concentrates on 2 types of skepticism)
(Med. I) (Med. II)
God (no deceiver)
External 1. My idea of God (III)
World 2. My contingent
(Meds. III-VI) existence (III)
3. The ontological
argument (again) (V)
(That piece of wax)
Radical (General) Skepticism
False Foundational Belief
False Foundational Belief
False Foundational Belief
If the underlying foundations of our beliefs are false, then it is possible that all of our beliefs are false too!
What are the underlying foundations of my beliefs?
Descartes’ Refutation of Radical Skepticism
“Cogito ergo sum!”
What does this mean?
“I think; therefore I am.”
Discourse on Method (1637)
I cannot doubt the truth of the statement, “I exist.”
I can't think that I am not thinking because then I am thinking; and if I am thinking, then I must exist. To doubt my own existence, I must exist!
Radical (general) skepticism is refuted.
The Mind-Body Problem &
Descartes’ Psycho-Somatic Dualism
Metaphysical Dualism: Reality is two-dimensional, partly material and partly non-material (minds, ideas, souls, spirits, consciousness, etc.).
Metaphysical Materialism: Reality is nothing but matter-in-motion-in-space-and-in-time. There are no non-material realities.
Metaphysical Idealism: Reality is nothing but Mind, Idea, Soul, Spirit, Consciousness, etc. Matter does not exist (it’s an illusion?).
Can you doubt the existence of your body (as well as other physical things)?
Why or why not?
Bryan Magee, The Great Philosophers (Oxford 1987)
Descartes' piece of wax
(What is this about?)
D' piece of wax is a physical object.
How is it known? Through the senses? Through the power of imagination? Through the intellect (judgment, intuition)?
(1) skepticism concerning the existence & nature of the “external world”
(2) the existence of God
“I must, as soon as possible, try to determine (1) whether or not God exists and (2) whether or not He can be a deceiver. Until I know these two things, I will never be certain of anything else” (Text, 289).
Why does Descartes say this?
Reasons for believing (1) that there are things outside myself, (2) that these external things cause my ideas of those things in my mind, and (3) that my ideas of external things “resemble” (accurately represent) the things themselves*:
*The epistemology represented by (1), (2), & (3) is known as “Representationalism.”
I have a strong natural inclination to believe the preceding three propositions.
(Do these reasons “clearly & distinctly” prove that Representational Realism is true?) (See 289-90)
And isn’t it obvious that substance is more real than mode or accident?
must be caused to be in the mind, and
the cause of any effect must be sufficient to produce its effect, i.e.,
there must be at least as much reality in a cause as is represented in its effect.
He also believes that ideas cannot represent more reality (anything greater or more perfect) than is in the things the ideas represent.
But is this last point true? Suppose I perceive an automobile with a dented fender &, from my perception, an idea of the car arises in my mind. Why can’t I think of the car as NOT having a dented fender?
How might Descartes respond to this criticism?Descartes thinks of ideas as
Could be composed from my ideas of myself, physical objects, and God (how?)
What about physical objects?
these are only modes of existence, and, as a substance,
“I” have more reality than these modes and “I” am therefore sufficient to cause my ideas of them.
I could be the cause of my ideas of both the primary and secondary qualities
of physical objects.
to produce the idea of God (an infinite substance)
from within myself (a finite substance).
for the existence of God . . . .
an infinite and independent SUBSTANCE, all-knowing and all-powerful, who created me and everything else . . . . ” (Text, 291)
This idea represents more reality than there is in myself (since I am finite, limited in knowledge & power, etc.). Thus, the idea of God must be caused to be in my mind by something other than myself. And . . . .
it follows necessarily that my idea of God must be caused by God Himself; and if God is the cause of my idea of God, then
God must exist!
since God is a being more perfect than myself.
How could I, merely from within myself, form the idea of a being more perfect than myself?
In that case, my idea would represent more reality than there is in its cause.Descartes’ main point here is
Only God is a sufficient cause of the idea of God in my mind.
1. All events are caused.
2. A cause must be sufficient to produce its effects.
3. My idea of a perfect being is a mental event.
4. Only a perfect being is a sufficient cause of my idea of a Perfect being.
5. If a perfect being is the cause of my idea of a perfect being, then a perfect being exists.
6. A perfect being (God) exists.
but my existence is not necessary -- it is contingent (i.e., my non-existence is conceivable, logically possible) -- which means
that I must be caused to exist (at every moment of my existence) by something other than myself (292-3).
whose existence is necessary (rather than contingent).
Furthermore . . . ,
1. All contingent beings must be caused to exist.
2. I exist as a contingent and thinking being, with the idea of a perfect being in my mind [and as contingent, I must be caused to exist--premise 1].
3. If something causes existence only if it is itself caused to exist, then its causal series is infinitely long.
4. An infinite (or infinitely regressing) series of causes leading up to my present existence is logically impossible, since, in that case, I could never begin to exist [i.e., I would have no existence at all].
5. A cause must be sufficient to produce its effects.
6. To be a sufficient cause of my existence, the "first cause" of my existence must be a necessarily existing [premises 4 and 5] and thinking being possessing the idea of perfection [premise 2].
7. The "first cause" of my existence is the cause of its own idea of perfection and is therefore, itself, a perfect being [otherwise it would not be "first"].
8. A perfect being (God) exists.
On the Problem of Error
Free will &
Slides on Meditation IV under construction – but see next slide for a brief summary….
Meditations V & VI
the existence of the external world
for the existence of God
(the ontological argument again)
being) were possible, then existence would not be
part of God’s essence (that is, existence would not
be a property of the divine nature).
2. If existence were not part of God’s essence (that is,
a property of the divine nature), then God would be
a contingent (rather than necessary) being.
3. The idea of God as a contingent being (that is, the
idea of an infinitely perfect being with contingent
rather than necessary existence) is self-contradictory.
4. It is impossible to think of God as not existing.
5. The nonexistence of God is impossible.
is the basis of certainty about everything else.
(There's a lot more in the 6th Meditation than is covered in this presentation…so far.)