Outline of Descartes’ Meditations 6
I. Descartes primary goal in Meditations VI is to prove the existence of material objects. He
has two secondary goals:
a. To show that the mind is distinct from the body. This is essential to show that the
Intellect – which gives us clear and distinct knowledge – is distinct from Sense
Perception. The Intellect is an as aspect of us as thinking things –minds. Sense
Perception is part of the body.
b. To show that, if we are careful, we can rely on sense perception to give us
knowledge of material objections.
II. Para 1: Descartes already believes he has established that it is possible that material objects
could exist. He has a clear and distinct idea of what it is for a material object – an extended
thing (a thing taking up space) – to exist. See the Wax Example. All he needs for this is
geometry, which he knows a priori. Now he needs to show that these things actually exist.
III. Para 2 and 3: Digression on the distinction between the Intellect and the Imagination.
The main point is that, though we may not be able to imagine something clearly (like a
thousand sided figure), we can conceive of it clearly and distinctly using our Intellect. (n.b.
One of the reasons we cannot imagine a thousand sided figure is that it is nearly impossible
to distinguish one from a perfect circle just by looking at it, unless it is very big.) Descartes
ends this section by supposing that the imagination is effect the ideas in his mind have on
his body.
a. Is he right that we can clearly and distinctly conceive of a figure like this?
b. Can we do it without the imagination?
IV. Para 4: Descartes acknowledges that mathematics gives him knowledge of possible material
objects – objects that could exist. But it is only through sense perception that he has
knowledge of actual objects. That is why he must investigate sense perception in order
to prove that material objects exist. As he says, “I want to know whether the things that
are perceived through the senses provide me with any sure argument for the [actual]
existence of bodies.”
V. Para 5: The Strategy of the Chapter: The rest of the chapter has three parts, the first two a
review of his initial naiveté about his senses and then his doubts. The third is a discussion
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is an argument that sense perception does reveal facts about material objects, but it is often
mistaken. Thankfully, we can avoid its errors if we are very careful. Here is how he explains
the three steps:
a. Part 1 - “…[I will g]o back over everything that I originally took to be perceived by
the senses, and reckoned to be true; and I will go over my reasons for thinking this.”
b. Part 2 - “… [I will s]et out my reasons for later doubting these things.”
c. Part 3 - “… [I will c]onsider what I should now believe about [things perceived by
the senses].
VI. Para 6: Part 1 Sense perceptions happen to us involuntarily – we do not choose to have
them happen – and are more vivid than those we imagine. So it seemed the best explanation
of why we have them is that something external to us – material objects – were causing
them.
VII. Para 7: Part 2 Now Descartes goes over his doubts from Meditations 1:
a. My sense perceptions can be mistaken, for example about the size of a tower.
b. I could be dreaming.
c. I could be “so constituted” as to always make mistakes about what I am perceiving.
VIII. Para 8: Part 3 Here he announces that he will argue for the conclusion that we should not
reject everything from the senses, but we also should not accept everything from them
either. We will look at his argument step by step to see why we should accept anything
from the senses at all, and what exactly we should not accept from them. This argument
runs from Paragraph 9 – End.
IX. Para 9 – Mind-Body Dualism:
a. If I can conceive of myself independently of x, then it is logically possible that x be
separated from me. (For Descartes, God could do the separating. But all we need to
suppose is that it be possible for me to exist separately from x).
b. If x can be separated from me, then x is not a necessary part of me.
c. I can conceive of myself without my body.
d. Therefore, it is logically possible that I can be separated from my body.
e. Therefore, my body is not a necessary part of me.
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X. The Argument for Dualism, A Criticism:
a. The argument relies on the principle that: If x can be conceived of without y, then
x can be separated from y (and so is not a necessary part of y).
b. Consider the Guitar Objection: I can clearly and distinctly conceive of a
(standardly-tuned, 6-string acoustic) guitar as a stringed musical instrument with
a certain range of tones produced by reverberations in a hollow body. I can also
clearly and distinctly conceive of a piece of wood as something carved from the
remains of a tree. So, I can conceive of a guitar and a piece of wood independently
of each other. But it does not follow that they are different things. If I try to separate
my guitar from its wood by smashing the wood, my guitar won’t survive, even in
some non-physical form. If I burn my guitar to destroy it (as an offering to Elvis,
say), I also destroy the wood. If this objection is right, then Descartes cannot rely
on the principle in (a). [Note, this objection comes from Plato. There is a nice
version in the Rae Langton. I’ve added detail.]
XI. Para 10 The Argument that Material Things Exist (Remember this was the goal of this
Meditation)
a. I have ideas of material things.
b. The Causal Adequacy Principle: A Cause must have at least as much reality as its
effect.
c. Argument by elimination: The ideas cannot come from me because they are
produced without my co-operation and often against my will, not by God otherwise
he would be a deceiver, so they must be produced by material things.
d. Therefore, material things exist
e. (Since the evidence for this conclusion came through my senses, my senses must
be able to give some knowledge of material things.)
XII. Step 2: Show what kind of knowledge we can have of material things through our senses.
a. God is not a deceiver.
b. Therefore, we will not go fundamentally wrong in our knowledge of the world if we
form our clearest and most distinct perception of it. Only the Mind can provide
knowledge of the world. The body gives us images of the world that resemble
nothing in it.
c. The only clear and distinct conception we can have of things is that given by
geometry, a conception of things as extended in space (See the Wax Example).
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d. Sense perception gives us a mistaken image of the world as containing many more
features than this – colours, feels, smells, what will later be called secondary
qualities. These, Descartes argues, are the effects of how material things affect our
Body, our sense organs. We must use the Mind, Reason, to strip away these qualities
from our judgments about the world because those qualities are not actually in the
objects themselves. If we did say things like, “The grass is green,” we would say
something false.
e. The actual features of material objects – for Descartes just the objects extension in
space – will be called their primary qualities. If we constantly use our God-given
reason to correct our senses, we won’t make false judgments. Instead of “The grass
is green,” we need to “The Grass is such as to appear green to me” if we are to say
something true.
f. Other examples:
i. Not “That cheese reeks” but “That Cheese is such as to cause an unpleasant
sensation in me.”
ii. Also, we should use our memory to correct for optical illusions. Not “That
tower is small.” But “That tower appears small but my memory reminds me
that it is just lower down in the city.”
g. Why would God give us sense organs that produced images of the world that
resemble nothing in it? Descartes answer: The sense organs are for determining
what is good or bad for our bodies, not for giving us knowledge of how the world
actually is. (N.b. Since Descartes thinks non-human animals are only bodies, they
have no knowledge of the world. Only humans and God have that.)
XIII. Problems with Conclusion
a. Is being able to say “That grass, which is only an extended substance, appears green,
fragrant and sharp to me” enough of a victory over the Demon? This might depend
on whether you think Descartes is out to (a) put common sense on a firm
foundation or (b) put the New Science on a firm foundation. Physics still describes
a world very unlike our experience of it, and explains how our experience is so
different that the world itself in terms of how that world affects our senses. So, does
Descartes win? Or the Demon triumph?
b. There is a debate over how to understand primary and secondary qualities. The
SQA knows about this, so you should. Here are two versions:
i. The qualities are in us not the object. The greenness of the grass is simply
the experience we have on being confronted with the grass.
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ii. The qualities are actually in the object. A green object is an object whose
surface is such as to cause the experience of greenness in the right
circumstances (say, in the light).
c. It might be possible to get rid of the distinction altogether. Suppose we said that
green just was the wavelength of light that caused people to see green. Then we say
that grass is green when it reflects this light (in normal circumstances). Then, we
have defined greenness in terms of the primary qualities of the object, not in terms
of how green things appear to us. We could do the same thing for the reek of Stilton.
But many people feel this would leave out the unpleasantness of the smell, the
greenness of the experience of green, etc. Those things happen in us, not in the
object.
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