PHL105Y Introduction to Philosophy Wednesday, November 1, 2006

1
PHL105Y Introduction to Philosophy Wednesday,
November 1, 2006

• For Mondays class, read Descartes Second
  Meditation.
• See Live Theatre at UTM. Theatre Erindale
  presents Radium Girls, November 1-4. Details
  www.theatreerindale.com.
• Tutorials continue this Friday. For this week,
  answer one of the following two questions, in
  about 200-250 words (about one typed
  double-spaced page) hand in the hard copy to
  your TA at the beginning of Fridays tutorial.
• If I cant tell whether I am presently dreaming
  or awake, what sorts of things does Descartes
  think I couldnt know? What sorts of things
  might I still claim to know, even if I dont know
  whether Im dreaming?
• What purpose is served by the introduction of an
  evil genius, supremely powerful and clever at
  the end of the First Meditation?

2
Introduction to Descartes

• (René Descartes, 1596-1650)
• Meditations published in 1641

3
Background to the early modern period

• In the middle ages, European science is dominated
  by the intellectual tradition of Aristotle.
• The earth is thought to be at the centre of the
  universe the sun, moon, and planets are lodged
  in a series of clear celestial spheres which
  revolve around us
• Each of the four elements (earth, water, fire,
  air) has its own guiding principle. Earth tends
  to sink, fire tends to rise, and so on.
• The laws of nature are different for things on
  the earth and in the heavens

4
The pre-modern view

• Nature is a book, whose meaning may be read in
  the heavens (or macrocosm), or in the human (the
  microcosm) everything revolves around us, and
  can be understood in terms of us

5
The pre-modern view

• Paracelsus (1493-1541) The whole world surrounds
  man as a circle surrounds one point. From this
  it follows that all things are related to this
  one point, no differently from an apple seed
  which is surrounded and preserved by the fruit
  External nature moulds the shape of internal
  nature, and if external nature vanishes, the
  inner nature is also lost for the outer is the
  mother of the inner. Thus man is like the image
  of the four elements in a mirror if the four
  elements fall apart, man is destroyed. There
  are two kinds of created things heaven and the
  earth are of one kind, man is of the other.
  Everything that astronomical theory has
  profoundly fathomed by studying the planetary
  aspects and the stars .. can also be applied to
  the firmament of the body.
• -source Paracelsus Selected Writings, N.
  Guterman, trans., pp. 112-14

6
The pre-modern view

• An early 17th-century argument intended to refute
  Galileos announced discovery of the moons of
  Jupiter
• There are seven windows given to animals in the
  domicile of the head, through which the air is
  admitted to the tabernacle of the body, to
  enlighten, to warm, and to nourish it. What are
  these parts in the microcosmos? Two nostrils, two
  eyes, two ears and a mouth. So in the heavens,
  as in a macrocosmos, there are two favourable
  stars, two unpropitious, two luminaries and
  Mercury undecided and indifferent. From this and
  from many other similarities in nature, such as
  the seven metals, etc., which it were tedious to
  enumerate, we gather that the number of the
  planets is necessarily seven.
• source S. Warhafts introduction to Francis
  Bacon a selection of his works, Toronto, 1965,
  p.17

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What is at the centre of the universe?

• Note that our senses seem to tell us that the
  earth is standing still and everything is going
  around it this is the common sense position
• What speaks in favour of the idea that we are
  hurtling through space around the sun?

8
What is at the centre of the universe?

• New technology helps to shed light on this
  question (Galileos 1610 discovery of the moons
  of Jupiter give a clear example of something that
  isnt revolving around our planet)
• The motion of the planets is also crucial
  Copernicus publishes his On the Revolutions of
  the Heavenly Spheres 1543.
• Link to a discussion of some of the complex
  reasoning involved.

9
A choice between criteria

• The old geocentric theory seems to be supported
  by the senses and common sense
• The new heliocentric theory is simpler more
  conceptually elegant
• Which considerations provide a better guide to
  the truth?

10
Conflict between old theories and new ones how
to respond?

• We could be dogmatic about the old theory
• We could settle for scepticism
• We could search for a philosophical argument to
  support the new one

11
Scepticism

• Michel de Montaigne (1533-1592) For three
  thousand years the skies and the stars were all
  in motion everyone believed it then Cleanthes
  of Samos or, according to Theophrastus, Nicetas
  of Syracuse decided to maintain that it was the
  Earth which did the moving, revolving on its axis
  through the oblique circle of the Zodiac and in
  our own time Copernicus has given such a good
  basis to this doctrine that he can legitimately
  draw all the right astronomical inferences from
  it. What less are we to learn from that, except
  not to worry about which of the two opinions may
  be true?
• -source An Apology for Raymond Sébond, pub.
  1580

12
Scepticism

• Montaigne also wonders about our knowledge of
  God particularly, he is worried that God cannot
  be known because he is too great
• What can be more vain, for example, than trying
  to make guesses about God from human analogies
  and conjectures which reduce him and the universe
  to our own scale and our own laws, taking that
  tiny corner of intellect with which it pleases
  God to endow the natural Man and then employing
  it at the expense of his Godhead? (from
  Montaignes Apology)

13
Scepticism

• We wish to make God subordinate to our human
  understanding with its vain and feeble
  probabilities yet it is he who has made both us
  and all we know. Since nothing can be made from
  nothing God could not construct the world
  without matter. What! Has God placed in our
  hands the keys to the ultimate principles of his
  power? Did he bind himself not to venture beyond
  the limits of human knowledge? (Apology, p.94)
• We can notice the municipal laws God seems to
  display to us locally we cant tell the real
  laws of nature nature is in the hands of a
  mysterious Being God could have made it true
  that 1010 does not equal 20 our science cant
  pretend to grip the truth

14
Descartes challenge

• To explain why the new science is better than the
  old, and to fight scepticism
• we should not suppose that skeptical philosophy
  is extinct. It is vigorously alive today (he
  goes on to describe it as the leading
  philosophical position among those who would
  reject the scholastic approach) or find nothing
  to satisfy them in philosophy as it is ordinarily
  practiced.

15
Descartes First Meditation

• (René Descartes, 1596-1650)
• Meditations published in 1641

16
The motivation and the method

• Several years have now passed since I first
  realized how numerous were the false opinions
  that in my youth I had taken to be true, and thus
  how doubtful were all those that I had
  subsequently built upon them.

17
The motivation and the method

• I realized that once in my life I had to raze
  everything to the ground and begin again from the
  original foundations, if I wanted to achieve
  anything firm and lasting in the sciences.

18
The motivation and the method

• I realized that once in my life I had to raze
  everything to the ground and begin again from the
  original foundations, if I wanted to achieve
  anything firm and lasting in the sciences.
• Why should one need to clear away everything to
  achieve stable progress in science? What are the
  foundations here?

19
Destroying all ones opinions

• If Descartes decides that if he finds any reason
  to doubt an opinion, he will suspend his belief
  in it.
• Why withhold assent from all opinions that are
  less than perfectly certain? (Why not just try
  to weed out the beliefs that are obviously
  false?)

20
Destroying all ones opinions

• Descartes will not survey each opinion
  individually. Why not?
• What is the alternative to going through ones
  opinions one-by-one?

21
Destroying all ones opinions

• because undermining the foundations will cause
  whatever has been built upon them to crumble of
  its own accord, I will attack straightaway those
  principles which supported everything I once
  believed.
• Is it plausible that our beliefs are supported by
  principles in that way?

22
The first principle the senses

• Surely whatever I had admitted until now as most
  true I received either from the senses or through
  the senses.
• But Descartes points out that our senses
  sometimes deceive us.

23
The first principle the senses

• However, Descartes notes that sensory illusions
  tend to mislead us about very small and distant
  things thinking about sensory illusions cant
  yet give him a reason to doubt that he is sitting
  by the fire looking at a piece of paper right in
  front of him

24
The dreaming argument

• Descartes mentions a dream in which he is seated
  by the fire in his dressing gown why such a
  mundane dream?
• A dream so hard to distinguish from everyday life
  raises the deepest concerns about the reality of
  our regular waking life.

25
The dreaming argument

• Descartes concludes that there are no definitive
  signs by which to distinguish being awake from
  being asleep.

26
The dreaming argument

• Let us suppose, for the sake of argument, that we
  are all dreaming. What can we still know?

27
The dreaming argument

• Let us suppose, for the sake of argument, that we
  are all dreaming. What can we still know?
• We cant know about particulars (I am looking at
  this very desk) we might still be able to know
  about something more general or abstract

28
The dreaming/painting analogy

• When he creates images of fantastic creatures,
  the painter needs to (1) take parts from real
  things he has seen, or, if not that, then at
  least (2) use real colours/ paint (so the raw
  materials of the painting are real, even if the
  painting represents something totally fictitious)
• Does representation in general have raw
  materials? What are the raw materials of
  imagination?

29
The dreaming/painting analogy

• What are the raw materials of imagination?
• corporeal nature in general, together with its
  extension, shape, size, number, place, time,
  etc.
• Even in dreams, you cant imagine a non
  spatio-temporal object, or a five-sided triangle
  there are rules for representation

30
The dreaming/painting analogy

• If there are rules for representation, then maybe
  we can know things in virtue of these rules, even
  if our representations are all depicting unreal
  objects (say, if we are dreaming).
• So perhaps we can know arithmetic, geometry,
  abstract sciences, even if we cant know physics,
  astronomy, medicine (Query why couldnt we
  know, say, astronomy if we were dreaming?)

31
Principle 2 the intellect

• Descartes now needs to find a reason to doubt
  even the abstract sciences
• Why is it hard to find a way to doubt that 224?

32
Principle 2 the intellect

• Descartes now needs to find a reason to doubt
  even the abstract sciences
• Why is it hard to find a way to doubt that 224?
• Suggestion its built into my nature to believe
  that sort of thing

33
The origin of my nature

• If its built into my rational nature to believe
  that squares have four sides or that 235, I can
  still worry

34
The origin of my nature

• If its built into my rational nature to believe
  that squares have four sides or that 235, I can
  still worry
• ..where does my rational nature come from? How
  do I know that the things I am built to believe
  really are true?

35
Where does my rational nature come from?

• My nature must come from one of these two
  sources
• 1. God
• - or -
• 2. Some source other than God

36
The argument concerning the origin of my nature

• God is either the source of my nature or he
  isnt.
• If he is, I have reason to doubt everything.
• If he isnt, I have reason to doubt everything.
• I have reason to doubt everything.

37
If God is the origin of my nature

• Couldnt an all-powerful God have brought it
  about that it just seemed to me that there was
  space, time, number, and so on, when really these
  things are not the way I think?

38
If God is the origin of my nature

• Couldnt an all-powerful God have brought it
  about that it just seemed to me that there was
  space, time, number, and so on, when really these
  things are not the way I think?
• Note that we cant just say a good God wouldnt
  let me go astray we do make mistakes, so if
  there is a God, he or she doesnt seem to mind
  that we make mistakes sometimes

39
If God is not the origin of my nature

• We havent (yet) proven that God exists for
  those who doubt that, is there also a reason to
  doubt the apparent deliverances of the intellect?

40
If God is not the origin of my nature

• We havent (yet) proven that God exists for
  those who doubt that, is there also a reason to
  doubt the apparent deliverances of the intellect?
• Lets say I was created by a series of accidents,
  or any cause less perfect than God surely I have
  all the more reason to doubt that my intellect is
  perfectly in tune with the truth

41
Widening doubts in the First Meditation

• Thinking about sensory illusions gives Descartes
  reason to doubt sense-based beliefs about small
  and distant things
• Thinking about dreams gives Descartes reason to
  doubt all his sense-based beliefs
• Thinking about the origin of his nature gives
  Descartes reason to doubt all his beliefs,
  including abstract/intellectual ones

42
The evil genius

• Descartes decides to suppose that he is facing an
  evil genius, supremely powerful and clever, who
  has directed his entire effort at deceiving me.
• Why?

43
The evil genius

• Before the evil genius comes on the stage,
  Descartes claims that he has found reason to
  doubt all of the things I once believed to be
  true.
• So the evil genius, supremely powerful and
  clever, who has directed his entire effort at
  deceiving me does not give us any new reasons to
  doubt.
• What does this strange figure contribute, then?