Download Aristotelian Background I

PHI2391A:
Rise and
Fall of
Aristotelian
Science
2.0
Aristotle
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Science & Philosophy of
Science begin with Aristotle
Who was Aristotle?
384-322 BC Born: Stagira
(The Stagirite)
 Student of Plato
 Founder of the
Lyceum/Peripatetic school
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Who was Aristotle?
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First “systematic” thinker in the
philosophical tradition
Prior to Socrates/Plato (presocratics):
Various schools of learning
Parmenides, Zeno, Thales,
Heraclitus
Propose new ways of thinking
Explanations of the origins of
the universe
Nature of matter
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Nature of change
Who was Aristotle?
Ways of describing world
that are opposed to
 Myth/Religion
 Philosophy at its origin
irreligious
 Early consequence:
Socrates put to death by
Athenians
 We would say: seeks
“natural” explanations
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Who was Aristotle?
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Socrates, his student Plato,
initiate school of philosophy
- The Academy
 Central doctrines:
 Theory of Forms
 Theory of Recollection
Plato
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All beings have (participate in)
“forms”
Not spatio-temporal/material,
but unchanging
Material world consists of copies
of the forms
Knowledge consists in grasping
formal character of things
Material objects not real
Learning a kind of
“remembering” (mathematics)
Who was Aristotle?
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Aristotle rejects Plato’s
doctrine of forms (“School
of Athens”)
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Importance for us: theory of
change
The problem of
change
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Zeno’s paradox
“Eleatic” (Elea) paradox of
being and change
 In change a thing (a being)
becomes something different
 Since it is not what it becomes,
in change a being (what-is)
becomes a non-being (what-is-
not)
 Conclusion: there is no
change/becoming
 Being simply is
The problem of
change
Platonic “solution”: what is
is a form
 Material objects are
copies/shadows of forms
 As non-beings, they can
change, but forms - beings never change
 Material objects are not,
they merely appear
 They are seemings,
“phainomena”
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Aristotle on change
and forms
Aristotle rejects Plato’s
“other world” theory
 Beings have forms, but
these beings are in this
world:
 Animals, rocks, trees,
humans are all be-ings So
how can they change?
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Form & matter
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The beings of this world are not
just forms
 They are “informed matter”
 Matter (Gr. hylé - wood, Lat.
materia) is not what we think of
as matter
 Matter is that aspect of a thing
which is not its primary being
 Each thing has a primary being
that makes it “what it is” (later:
Lat.“essentia” from “essere” to
be”)
Form & matter
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So a horse has the
form/essence of “horseness”
(Plato would have said this)
 But it also has aspects of its
being that are not primary. For
instance qualities or properties
 Colour, height, weight, softness,
hardness
 The “total horse” is a composite
of its form (horseness) and the
material properties
How does this relate
to the problem of
change?
Aristotle: Two fundamental
species of change
 (1) Change of properties
 (2) Coming-to-be
[“generation”] and passingaway [“destruction”]
 In (1), the essence/being of
a thing remains the same (it
“be’s” what it is)
 But the matter changes (it
grows or shrinks, changes
colour, etc.)
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How does this relate
to the problem of
change?
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In (2) the being/essence of a
thing changes
But then Parmenides and Zeno
kick in:
If the being changes, the thing is
not (is no longer) so the change
is not a change
It is a destruction
Similarly, what is after the
change is new
It is a “coming-to-be” or a
generation
We will return to (1) - qualitative
change - below
Form, matter and
change
The form/matter composite
thus a theory fundamentally
addressed to problem of
change
 Theories of this sort theories that say what the
fundamental character of
being is are called
 Metaphysical theories
 Word does not exist for
Aristotle:
 “First philosophy” (Physics
194b14)
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Form/matter and
generality
There is a connection
between being and
language
 Culminates in mature
Aristotelian view (cf. Losee,
p. 12-13)
 What we call a
“correspondence theory of
truth”
 But is there in Plato’s theory
of forms
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Forms and language
A form makes a thing what it
is
 Plato’s forms are unique
 Each appears multiply in the
spatio-temporal world
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There are many horses,
each of which is a horse
(Compare: Hydrogen
atoms)
 For Plato, each individual
horse is a copy of the ideal
form of the horse
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Forms and language
The theory explains why we
- correctly - use one word to
refer to this class of
individuals
 They are all instances of the
same form
 And when we correctly call
something a horse
 We say of that individual
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that it partakes in/manifests
that form
Forms and laws
Use of formal language
allows the formation of
general laws
 “Horses nurture their
young”
 “Pie-O-My is a horse”
 “Pie-O-My will nurture its
young”
 It permits us to formulate
generally true propositions
 Propositions about kinds of
things
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Matter and
individuality
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In Plato’s theory, the horses are
copies of the ideal horse
Knowledge (philosophy/science)
is knowledge of forms
It is expressed in general term in
language
In this sense, language is
always about the general case
We do not have knowledge of
specific cases
Matter and
individuality
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In Aristotle’s theory, there are
no ideal forms
 There is just the group of
horses, which are form/matter
composites
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The matter individuates the
horses
 Each has different properties
 Each is in a different place, has
a different shape, size and
colour
 Remember: “matter” means all
kinds of properties
Knowledge in
Aristotle
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But just as in Plato, knowledge
is always of forms
 Even properties, like redness,
are considered formally when
we do science
 We never talk about this red
patch
 But about red patches
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For Aristotle, everything, even
properties, have being, or form
 But properties only have being
and form in a secondary sense
Change in Aristotle
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We said: aside from creation
and destruction, change for
Aristotle is qualitative
 Whenever a thing changes, its
primary form remains the same,
and the matter changes
 The primary form is the being,
essence, nature of the thing
(horseness)
 The matter is the set of
properties that individuates it
Change in Aristotle
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The various kinds of properties,
Aristotle calls categories
Include qualities like colour,
heaviness
Locations like above/below
(Being is also a special
category)
So a thing has a categorical
structure
And change is change of that
structure
For each category, there is a
corresponding kinds of change
(Physics 201a1-9)
Change in Aristotle
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Change is characterised by
a transition from potentiality
to actuality
“the actuality of that which
potentially is is … is
change”
 When the matter of a tree’s
leaves change from green
to red, what is potentially
red becomes actually red.
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Change in Aristotle
Matter, as the ground of
change, is potentiality
 When it takes on a form, it is
actualised
 Motions begin in potentiality
and end in actuality
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Change in Aristotle
The study of change is the
study of nature
 Greek physis, thus physics
 Aristotle: nature “a cause
and source of change”
(192a21)
 Physics is thus the science
that understands the causes
and sources of change
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Physics
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Remember the origins of
form/matter theory in Eleatic
paradoxes
 Would expect a connection to
the theory of motion
 Indeed, form and matter appear
as “causes” of motion
 Two other causes in addition
(Phys 195a20-27) :
 End (“final”, Lat. finis - end)
 Maker (“efficient”, Lat. facere to make, p.p. factum)
Change and causes
Let’s put together theory of
change and theory of
causes
 Change is a change within
categories
 The properties of a
being/form change, this is a
material change
 The causes of the change
are thus causes of the
alteration of properties
 While the thing remains the
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same (unless destroyed)
Change and causes
Question: Why does a
change take place?
 Because of the matter:
theory of elements
 Because of the form
 “…nature is the shape and
form of things which have in
them the source of their
changes” (Phys 193b1-5)
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Nature and techné
(art)
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Note that “source of their
changes” suggests what
Aristotle calls a cause
So the nature is the form of
a thing that has its causes
“in it”
 Aristotle distinguishes
between things “by art” and
“by nature”
 In both sort of thing, the
matter is there “for the sake
of” the form
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Nature and techné
(art)
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So the wood (remember
“matter” is the same word
as “wood” in Aristotle) of
the bed is for the sake of
sleeping on it
The bed has a form, but the
form was given to it by the
man who made it
 Thus matter and form are
un-naturally combined
 If you plant a bed, it sprouts
a tree, not a bed
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Nature and techné
(art)
Aristotle’s definition of
natural forms is deeply
influenced by understanding
of technical forms
 E.g. Phys 194a35f.
comparison of artificial and
natural objects
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“In the case, then, of
artefacts we make the
matter for the work to be
done, whilst in the case of
natural objects it is there
already.”
Nature and techné
(art)
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Note preceding distinction: the
nature of a rudder
There is the knowledge of what
it is for (the steersman)
There is the question of how it is
to be made
When both are combined, we
get a form/matter composite
where
The matter is in a form, for the
sake of an end
Causal structure
So the causal structure of
the rudder is:
 Material cause: wood
 Formal cause: shape
 Efficient cause: carpenter
 Final cause: steering
 Aristotle: in natural objects,
“the last three often
coincide” 198a24
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Natural entities and
change
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So the science of nature is
the science of things whose
form and matter are for the
sake of an end
 Primary example: animals,
plants
 Entities with organic
structure
 Aristotle calls the
form/nature of living things a
“psyché” (soul - principle of
life)
 But theory not restricted to
living things
Natural entities and
change
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Aristotle explains motion of
“inanimate” objects finally
as well
 Rocks fall because they
“tend” downwards
 It is in their “nature” to
move downward (change in
the category of position)
 (But not all change is
“natural” in this sense)
Natural entities and
change
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In an organic being, the matter
is organised for the form
 And the formal and final causes
coincide: organisms exists for
the sake of continuing to be
what they are
 And to reproduce (the end of
creating a new form)
 Grounds key notion: “essential
properties”
Essential properties
Different kinds of animals
have different forms, ways
of life
 In each case, the form and
matter of the animal
adapted to way of life
 Ultimate final causes:
nutrition, locomotion,
perception, intellection
 We have teeth “in order to”
eat
 We have eyes “in order to”
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see
Essential properties
and natural motions
Certain aspects of a thing
are essential
 “For its being”
 Those organisational and
material properties which
make it the kind of thing it is
 And motions that occur for
these essential ends are
“natural”
 Holds even for rock
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Essential properties
and natural motions
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Natural motion of rock:
falling downwards
 Forced motion: rock thrown
at bird by hunter
 The motion is for the sake of
something external to the
nature of the rock
 Rock will fall to ground once
the forced motion “wears
off”
Essential properties
and natural motions
Aristotle’s theory of physics
restricted
 Only a small subset of what
happens qualifies as natural
motion
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“Why should not everything
be like the rain?” (199a17)
 Aristotle speaks of
“necessary”, “automatic”,
“coincidental” motions
 These are things that “just
happen”
 For no reason (with no
cause)
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Essential properties
and natural motions
Among these are motions
due to impact,
displacement, etc.
 “Forced motions” (the
thrown rock)
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In general, motions not
directed towards an
essential (natural) end
The Platonic
Remnant
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Aristotle’s conception of science
retains Platonic elements
Knowledge (philosophy/science)
is knowledge of forms
So scientific knowledge unavoidably - becomes
knowledge of essential
properties of things
Particularly: knowledge of
natural forms which govern finally - natural motions
Where these are conceived
teleologically (Gr. telos - end,
goal)
Problems for Aristotle
Modern perspective:
Aristotle “unscientific”.
Why?
 No mathematics
 Final causes
 Large mass of “random”
events
 How would Aristotle defend
himself against these
charges?
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The status of
mathematics
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Mathematician is not a
natural scientist
 But: natural science can use
mathematics (Astronomy,
Phys 193b26)
 Why is he not a natural
scientist?
 What is mathematics about?
The status of
mathematics
Mathematics concerned
with forms, but not with
essential forms
 Mathematical forms are
shapes
 These fall under the
categories of size, position,
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direction
 So they are “accidental”
(non-essential) or, simply,
“material” aspects of things
 But they are considered
“separately” of any specific
thing
The status of
mathematics
Mathematics studies formal
characteristics of matter
 Not all such characteristics
 Those that are spatial
 Formally, because without
regard to specifics
 But material, because not
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concerned with essential
properties of individuals
The status of
mathematics
But - obviously - most
material properties, e.g.
colours, are not
mathematical
 And, “Odd and even,
straight and curved … can
be defined without change
but flesh, bone and man
cannot.” (Phys 194a4)
 I.e. they are not about
change
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Final causes and
random events
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Paul Feyerabend: Think of
Aristotle’s universe as one
which is “pulled forwards”
 Events are the material changes
of primary substances
(form/matter composites)
 Among the events, there are
some that happen “for” the form
of substances (independent
form/matter composites)
 So natural motions are forward
directed
Final causes and
random events
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Recall: motions begin in
potentiality and end in
actuality
 The universe consists of a
sequence of transitions from
potential to actual states
 But this sequence is
disrupted
Final causes and
random events
Automatic, coincidental
events coexist with the
natural motions
 May interfere with them
 Automatic motions - the
tripod collapsing (197b17) happen on a purely material
level
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But such purely material
events are scientifically
ungraspable
Random events
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Recall: Science is about general
forms and laws
Laws reflect the action of
essential forms on matter
They are general because they
are formal
Matter is the ground of
potentiality and change
Automatic events happen
spontaneously, i.e. there is no
reason why they should happen
In this sense, there can be no
science of matter for Aristotle