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\title {Descartes \\ Lecture 05}

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Lecture 05:

Descartes

[email protected]

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Descartes’ organising question is ...

How can we acquire knowledge about the essential nature of the bodies located outside us?

fundamental physical properties (e.g. extension)

So far ...

Not by sensory perception alone
- sensory perceptions do not resemble (The World)
- argument from doubt (Meditation 1)
There is a nonsensory route to knowledge that I exist,
which provides a ‘first principle’

why?

Doubt is necessary to establish ‘anything at all in the sciences that is stable and likely to last’

I think Descartes didn’t care about ordinary notions of knowledge. He was not arguing about whether you know where your pet tortiose is (student example). He is arguing about how you can know which are the fundamental physical properties of material bodies.

Last week on Tuesday, I said the aim was to understand this. I suggested it was because doubt shows us that we cannot know the essential nature of bodies by means of the senses. In explaining this, I contrasted two interpretations of Descartes’ position ...

In this lecture I want to go a little deeper ...

Two Interpretations

1. The sciences need a metaphysical foundation.

2. This foundation must include a refutation of scepticism.

‘I had seen many ancient writings by the Academics and Sceptics on this subject, and was reluctant to reheat and serve this precooked material’

Second Replies

Meditations (Synopsis)

The usefulness of extensive doubt ‘lies in freeing us from our preconceived opinions, and providing the easiest route by which the mind may be led away from the senses.’

1. What is it to be led away from the senses?

2. Why does Descartes want to lead us away from the senses?

So the important thing about doubt is that it leads us away from the senses.

This raises two questions, which are my concern today ...

Wax

\section{Wax}

Descartes makes a striking claim in the Second Meditation ...

‘even bodies are not strictly perceived by the senses or the faculty of the imagination but by the intellect alone’

(Meditation 2)

Let’s start by contrasting this claim with the view he opposes, that of the Aristotelians ...

recall from lecture 1 ...

How can we acquire knowledge about the essential nature of the bodies located outside us?

Each body has a form, which is its essential nature.

When a body is perceived, your sensory perception resembles the body’s form.

Thanks to this resemblance, your sensory perception acquaints you with the forms (essential natures) of bodies.

Which of these claim’s does Descartes claim about the proper purpose of sensory perceptions justify us in rejecting?

wax

‘I can grasp that the wax is capable of countless changes, yet I am unable to run through this immeasurable number of changes in my imagination… The nature of this piece of wax is in no way revealed by my imagination, but is perceived by the mind alone’

(Meditation 2).

Sensory perceptions change.

The essential nature does not.

Therefore the senses cannot inform us about its essential nature.

Argument sketch: \begin{enumerate} \item Sensory perceptions of the wax change. \item The essential nature of the wax does not. \item Therefore the senses cannot inform us about its essential nature. \end{enumerate}

‘The Stoics claimed that each of us has many cognitive impressions, typically sense impressions of a particular sort, and that these cognitive impressions are in one way or another the basis for everything that we can know. A cognitive impression is one that “[1] arises from what is and [2] is stamped and impressed exactly in accordance with what is, [3] of such a kind as could not arise from what is not.”’ (Sextus Empiricus, Against the Logicians 7.248 (1997, 132–33) cited by \citealp[p.~72]{broughton:2003_descartes}).

Is this argument convincing?

‘Something which I thought I was seeing with my eyes is in fact grasped solely by the faculty of judgement which is in my mind’

(Meditation 2).

recall from lecture 1 ...

How can we acquire knowledge about the essential nature of the bodies located outside us?

Each body has a form, which is its essential nature.

When a body is perceived, your sensory perception resembles the body’s form.

Thanks to this resemblance, your sensory perception acquaints you with the forms (essential natures) of bodies.

Which of these claim’s does Descartes claim about the proper purpose of sensory perceptions justify us in rejecting?

So the wax refutes the idea that we can gain knowledge of things through the senses?

‘even bodies are not strictly perceived by the senses or the faculty of the imagination but by the intellect alone’

Meditation 2

Descartes uses the example of seeing the hat of someone and saying that you have seen a man walk past.

The point isn’t that you might be wrong. The point is that the senses do not get you to the person.

Sensory impressions of wax

Judgement that this is wax

Seeing hats and coats

Judgement that those are people

‘But then if I look out of the window and see men crossing the square, as I just happen to have done, I normally say that I see the men themselves, just as I say that I see the wax. Yet do I see any more than hats and coats which could conceal automatons? I judge that they are men. And so something which I thought I was seeing with my eyes is in fact grasped solely by the faculty of judgement which is in my mind’ \citep[p.~21; AT VII: 32]{descartes:1985_csm2}.

Meditations (Synopsis)

The usefulness of extensive doubt ‘lies in freeing us from our preconceived opinions, and providing the easiest route by which the mind may be led away from the senses.’

1. What is it to be led away from the senses?

2. Why does Descartes want to lead us away from the senses?

Led away from the senses ...

2. Sensory perceptions do not carry information about the essential natures of bodies (argument from Wax)

Does any of this imply that the senses deceive us?

Led away from the senses ...

1. Sensory perception alone does not enable you to know you are drinking coffee (argument from cosmic doubt).

2. Sensory perceptions do not carry information about the essential natures of bodies (argument from Wax)

Does any of this imply that the senses deceive us?

Does any of this depend on a demand for certainty?

Error

\section{Error}

‘I know by experience that I am prone to countless errors’

\citep[p.~38; AT VII: 54]{descartes:1985_csm2}

‘my errors ... are the only evidence of some imperfection in me’

\citep[p.~39; AT VII: 56]{descartes:1985_csm2}

Fourth Meditation

‘So what then is the source of my mistakes?

It must be simply this: the scope of the will is wider than that of the intellect; but instead of restricting it within the same limits, I extend its use to matters which I do not understand’

\citep[p.~40; AT VII: 58]{descartes:1985_csm2}

Fourth Meditation

What are these?

\emph{The intellect} is the faculty of representation. \emph{The will} is what affirms or denies something represented \emph{Judgement} occurs when the intellect represents something which the will affirms (or denies). \emph{Error} occurs when will affirms (or denies) incorrectly.

The intellect is the faculty of representation.

The will is what affirms or denies something represented

Judgement occurs when the intellect represents something which the will affirms (or denies).

Here is a representation. You cannot say that I have misled you until I tell you that it represents the route from your hotel to the metro station.

So the picture is this: the intellect passes images to the will. And the will decides what to do with them. Some it affirms or denies. Others it just hangs on a wall.

The intellect is the faculty of representation.

The will is what affirms or denies something represented

Judgement occurs when the intellect represents something which the will affirms (or denies).

‘So what then is the source of my mistakes?

It must be simply this: the scope of the will is wider than that of the intellect; but instead of restricting it within the same limits, I extend its use to matters which I do not understand’

\citep[p.~40; AT VII: 58]{descartes:1985_csm2}

Fourth Meditation

Ok, so now we get the picture?

The intellect is incapable of error (it merely represents).

Error occurs when the will affirms (or deines) incorrectly.

What should the will not affirm?

Now I hope you can see more clearly why there’s no implication that the senses deceive us.

Led away from the senses ...

1. Sensory perception alone does not enable you to know you are drinking coffee (argument from cosmic doubt).

2. Sensory perceptions do not carry information about the essential natures of bodies (argument from Wax)

Does any of this imply that the senses deceive us?

Meditations (Synopsis)

The usefulness of extensive doubt ‘lies in freeing us from our preconceived opinions, and providing the easiest route by which the mind may be led away from the senses.’

1. What is it to be led away from the senses?

2. Why does Descartes want to lead us away from the senses?

conclusion

In conclusion, ...

\section{Error and The Wax} The claim that bodies are ‘not strictly perceived by the senses’ plays an essential role in Descartes account of error. Since the senses do not strictly perceive bodies, they cannot be the cause of errors about bodies.

The Wax

‘even bodies are not strictly perceived by the senses or the faculty of the imagination but by the intellect alone’

Second Meditation

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Lecture 05:

Descartes

[email protected]

Wax

Error

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