Aristotle
Aristotle
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Lived 384-323 BC.
He was a student of Plato.
Was the tutor of Alexander the Great.
Founded his own school: The Lyceum.
He wrote treatises on physics, cosmology, biology,
psychology, politics, ethics, language, and logic to name
just a few.
• Was influential well into the 1600s.
• Was as much a natural scientist has he was a
philosopher—made detailed observations of plant and
animal life and devised detailed theories of change and
motion in the physical world.
Background
Aristotle and Plato
Strategy for understanding ancient views
about the mind.
1. Metaphysics: their view about the nature
of the world.
2. Their understanding of the mind as it is
informed by that worldview.
3. Importance to the history of psychology.
Aristotle and Plato
• Recall, Plato thought the universe was
divided into two realms: the material world
of the senses and the eternal immutable
world of the Forms.
• This was shaped by his study of
mathematics and had an impact on his
view of the soul (mind).
• The body belonged to the material world,
while the soul belonged to the forms.
Aristotle and Plato
• Aristotle inherited the problem of
universals from Plato.
• Recall, universals are merely the various
Forms, which explain the nature of the
sensible world.
• But there is an enormous difficulty with
Plato’s theory.
• What do you think it is?
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Aristotle and Plato
• The problem is to explain the relationship
between the realm of the Forms and
material objects.
• Plato became aware of these difficulties
later in his life (the population problem;
and the third man argument).
• Aristotle was also aware of this difficulty
and attempted solutions.
Aristotle and Plato
Aristotle and Plato
• Aristotle’s excursions into botany led him
to believe that change and growth in the
natural world result from a force in the
material objects themselves.
• Aristotle rejected Plato’s theory of the
Forms.
• Instead, he believed universals to be part
of the natural world.
Aristotle and Plato
• Aristotle’s solution was to replace the idea of two
distinct realms with the idea that material things
have dual aspects: all objects are a composite of
matter and form.
• In this way universals (Forms) become part of
the material objects that make up the material
world.
• In order to better understand this view we need
to have an account of Aristotle’s notion of
substance.
Aristotle on Substance
Aristotle on Substance
• ‘Substance’ refers to the basic elements of the
world—it is the thing that remains constant
throughout the change we see (e.g. the growth of
plants and animals; the movement of the stars).
There are three different concepts that fall
under this term:
1. Substance as matter.
2. Substance as form (or essence).
3. Substance as the combination of 1 & 2.
• The distinction between matter and form
is, roughly, what something is made of
and what makes it the kind of thing it is.
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Matter and Form
Marble
Bronze
Matter and Form
• Insofar as they are the same kind of thing,
they have the same form.
• What makes these statues the kind of
thing they are is that they portray the same
subject—the thinker.
• This is given by the shape of the objects.
• So the shape is the form.
• But they are composed of different
material (marble and bronze).
Same form different matter.
Matter and Form
Matter and Form
• In this case, both these statues are the
same kind of thing—they have the same
form.
• But although they both come from bronze,
they are different pieces of bronze.
• The matter is what individuates them—its
what makes them two distinct objects.
Same form different matter.
Matter and Form
• The same holds true of the natural world.
• Plants and animals of the same species have
the same form (or essence)—it is what different
members of the group have in common.
• The matter is what differentiates them from one
another.
• But (confusingly) form is also responsible for the
uniqueness of each object (e.g. its particular
shape).
• E.g. Your form (or essence) is what makes you a
human being but also the unique person you
are.
Aristotle on Change
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For Aristotle change was a
transformation from potentiality to
actuality governed by the laws of
causation.
For example, an acorn is potentially an
oak tree.
If the right conditions are met the
potential oak tree (found in the acorn)
becomes an actual oak tree.
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Aristotle on Change
4 Causes
1.
2.
3.
4.
Potentiality
Material cause: the material that makes up the object
(e.g. marble).
Efficient cause: the agent of change or the means by
which change is induced (e.g. the sculptor).
Formal cause: the expression of what an object is (e.g.
the shape of the statue).
Final cause: the end or purpose for a thing—why it is
done (the idea of the statue in the sculptor’s mind; as a
tribute to thinking).
Actuality
Aristotle on the Soul
The Definition of the Soul
1. Natural bodies (e.g. rocks, trees, water,
animals…) are substances in the sense
of composites of form and matter.
2. Some natural bodies are living, and
some are not.
3. Because a living body is a body of a
particular kind (living!), the body cannot
be the soul.
Aristotle on the Soul
• The soul is a substance—a fundamental
element of the world.
• Thus, it must be either matter, form or a
combination.
• All living things are composites of matter
and form.
• So the soul must be one or the other.
• But it can’t be matter because matter is
only potentially a living thing.
Aristotle on Change
• In living things the principle of change is within
the object itself.
• For example, an acorn ‘wants to become an oak
tree.’
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Aristotle on the Soul
• E.g. the difference between a living body
and a dead one is that one possesses a
soul.
• Thus, the body (tissue, bone etc.) cannot
be the soul.
• The body is merely what makes life
possible.
Aristotle on the Soul
• Soul must be a substance in the sense of
the form of a natural body having life
potentially within it.
• The difference between a body that is
potentially alive and one that is actually
alive is the presence of a soul.
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Aristotle on the Soul
Soul as the Form of Living Things
• In living things the form is what makes a plant or
animal a member of one species or another.
• An acorn becomes an oak tree because it has
the form or soul of an oak.
• Same species = same soul.
• Since soul can only enliven matter with a
particular kind of organization (having the right
parts for living), the soul is the actuality of a
“natural organized body.”
Aristotle on the Soul
Aristotle on the Soul
• But the soul is more than just a principle of life.
• It is also responsible for the naturally organized
body functioning in the way that it does.
• In the natural world, what makes something the
kind of thing it is (its form) is a principle of growth
and movement within the thing itself.
• Life is growth and movement.
• It is the specific nature of this power that
determines the species to which something
belongs.
• Things belong to a species in virtue of
what they do rather than how they look.
• E.g. there are certain activities that are
natural for dogs.
• It is the capacity for this kind of activity that
makes something a dog.
• Physical organization of the dog make this
activity possible, but the soul is what
makes this possibility actual.
Aristotle on the Soul
Aristotle on the Soul
• Consider an axe (Aristotle’s example).
• If it were a natural thing, its soul would be what
makes it an axe.
• This would be its ability to cut wood.
• But an axe is not a natural thing, for if it were, it
would be able to cut wood by itself.
• Living things have the power in themselves to do
the kind of things that make them the thing they
are (e.g. growth, reproduction, perception…)
• Consider an eye.
• If an eye were a living thing, sight would be its
soul, since that’s what makes it what it is.
• Eyes of living creatures see, in contrast to the
eyes of statues.
• Similarly, the power of sense (sensibility) is what
gives form to the sensible organs of the body.
• Thus, the soul of a living thing is like a hierarchy
of forms, each contributing to the
powers/abilities that constitute life for that
species.
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Aristotle on the Soul
• What we get here is functional account of
the mind.
• The mind (or soul) is understood in part by
how it makes actual the functioning of a
living thing.
• Unlike Plato, Aristotle believed the soul
was inseparable from the body—it would
be like asking “whether the wax and its
shape are one.”
Faculties of the Soul
1. Nutritive Soul: all living things have the
power to feed and reproduce.
2. Sensitive Soul: some also have the
powers of locomotion and perception.
3. Rational Soul: only human beings have
the power reason and reflection.
• All three are present in humans.
Aristotle on Perception
• For Aristotle, colour is, by definition something
that changes this transparent substance.
• And as a result of this change things are made
visible to the eye.
• This transparent substance is either active or
inactive—only when it is active is colour visible
through it.
• Light is the active state of this substance and
darkness is the inactive state.
Faculties of the Soul
• For Aristotle the various species form a
hierarchy according to the nature of their
activities.
• All grow and reproduce.
• But not all forms of life possess sensory organs
to perceive the world around them.
• This led him to propose different faculties of the
soul whereby a species is categorized in
accordance with the faculties they possess.
Aristotle on Perception
Vision
• For Aristotle colour is what lies
on the surface of visible objects.
• We see other things through a
transparent medium/substance
that exists between our eyes and
the surface of coloured objects.
• It is not visible, but is to be found
in, e.g., air and water.
Aristotle on Perception
• Fire excites the activity of this substance (efficient
cause), which is why we can see in the presence
of candle-light, sunlight etc.
• Fire produces light (in Aristotle’s terms).
• This now active substance in water or air (and
the eye) can then transmit the colour from the
surface of the object to the soul through the eye.
• The soul literally takes on the colours of the
things we see around us.
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The Passive Intellect
Thinking
• Aristotle considers thinking to be in part a passive
enterprise, somewhat like sense perception.
• The difference between it and sense perception
lies simply in what is perceived.
• Each sense is responsible for our awareness of
the particular qualities for which it is designed to
sense (the proper sensibles).
• Each quality acts on the sense organ in a way to
reproduce that quality (literally) in the soul.
The Passive Intellect
• The soul literally takes
on the form of the
objects it is thinking
about…passively.
The Passive Intellect
• Its like the way in which warm wax receives a
seal.
• Just as the warm wax can receive any
impression the mind can think about any
essence—take on any form.
• As a result, Aristotle thought the mind
did not have any essence of its own.
• E.g. eyes have there own nature—to become
coloured—this is why they can only perceive
colours.
The Passive Intellect
• Thinking then is the process by which the soul
acted upon by those things which are capable
of being thought.
• In thinking the soul takes on the nature of what
it is thinking about.
• What is capable of being thought about?
• The form (or essence) of the object.
The Passive Intellect
• Recall form is what makes an object the kind of
thing it is (essence).
• Imagine perceiving a galloping horse.
• We perceive it with our five senses…
• But how do we know it’s a horse (i.e. its
horseness)?
• We seem to take this for granted.
• There must be a faculty by which
we perceive the essences of things.
The Active Intellect
• Aristotle also though there was more to the mind
merely passively taking on forms.
• Recall the statue.
• For it to exist there must be material and
something that causes the material to become a
statue.
• In vision the analogue of matter is the faculty of
sight in the soul, which is potentially coloured.
• The cause of vision (taking on colour by the
soul) is fire.
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The Active Intellect
Aristotle on Memory
• The soul is the matter of thought—its potential to take on
different forms.
• But there must be an active cause to bring that about
(like fire in vision).
• But in this case there is no external cause—the mind is
its own cause of thinking.
• Thus, there must be an active mind that is the cause of
thinking.
• This accounts for the sense in which thought is a kind of
activity.
• The active intellect appears to be immortal since it is
separate from the body…controversial.
• Memory for Aristotle was the recall of
events that have passed—perception is of
the present.
• He presented the first associationist theory
of memory.
• Associationism: the doctrine that ideas
follow from one another in memory if they
were experienced in relation to one
another.
Aristotle on Memory
Aristotle on Memory
• Remembering for Aristotle, was the process of
following a chain of associated ideas to arrive at
the thing we want to recall.
• For Aristotle, associations are produced by
means of the law of association: similarity,
contrast, and contiguity.
• This idea still has force in modern psychology
(e.g. in behaviourism; protype theory…).
The laws of association
1. Similarity: we tend to be reminded of
something to the extent that it resembles what
we are currently experiencing (e.g.
AristotleÆPlato).
2. Contrast: sometimes we are reminded of
something to the extent that it means the
opposite of what we are currently experiencing
(e.g. blackÆwhite).
3. Contiguity: we will tend to be reminded of
things that were previously experienced with
what we are currently experiencing (e.g. salt
Æpepper).
Aristotle on Memory
Aristotle Summary
• Memory vs. recollection.
• Other animals have memory—which is a kind of
elementary matching of current sensations to
previous experiences (episodic memory?).
• It’s a kind of simple recall.
• Only humans have recollection—which is an of
inferential process. We don’t simply recall the
past we have to infer it on the basis of our
current experience (reconstructive).
• Aristotle continues a line of thinking that begins
with Pythagoras and is developed and changed
in Plato.
• The problem of universals motivated Aristotle’s
own view.
• The soul was (i) the source of life; and (ii) the
seat of the intellect.
• For Plato the soul is part of the Forms, but for
Aristotle the soul is part of the natural world of
material objects and living things.
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Aristotle Summary
• According to this new view, the principles by
which the soul operates are, in general, the
same as those that govern the change and
movement in other natural objects (e.g. rocks,
trees…).
• Even though there is some mention of the
eternal nature of the active intellect—the
operation of the intellect follows the same
pattern as that of sensory perception and
organic activity in general.
Aristotle Summary
• In making the mind part of the natural
world, Aristotle offers us the first great
naturalist theory—almost all modern
psychologists are naturalists.
• The natural world (as opposed to the
Forms) is the true object of study.
• His theory of sensory perception suggests
that perception gives us a direct and
reliable link to the world.
Aristotle Summary
Aristotle Summary
• Thus, our senses (observation!) provides the
best means of trying to understand the world.
• In this way, Aristotle is also the first great
empiricist/scientist—giving rise to what would
become the cornerstone of modern science.
• This is the first big move away from rationalism.
• His laws of causation provide the foundation for
later scientific thinking—influential well into
medieval times.
As in Plato we get…
• A theory of learning.
• A theory of memory.
• A theory of cognition.
• Anticipation of the nature/nurture debate—
movement towards the nurture side.
• Teleological explanation—is the beginning
of a kind of psychological explanation—
things done for reasons/purposes.
Thomas Aquinas
Thomas Aquinas
• Lived 1225-1274AD.
• The Catholic church came to prominence
around 500AD—1500AD.
• Christianity was the dominant religion.
• Aquinas was one of the greatest
interpreters of Aristotle’s work.
• He showed that Aristotle’s views could be
reconciled with Christianity.
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Thomas Aquinas
• For example, Aquinas’s 5 ways (arguments for the
existence of God) were developed on the basis of
Aristotle’s model of causation.
E.g. The argument from Motion.
1) Nothing can move itself.
2) If every object in motion had a mover, then the first
object in motion needed a mover.
3) This first mover is the Unmoved Mover, called God.
• This also made use of Aristotle’s cosmology and it’s
dependence on the Prime Mover.
The Scala Natura—The Great
Chain of Being
• Pure Actuality (Prime Mover)
– Humans (Rational)
– Animals (Sensitive)
– Plants (Nutritive)
– Non-living natural objects (e.g. rocks, bone..)
– The elements (earth, air, fire, water)
• Pure substance/Pure Potentiality
Thomas Aquinas
• The Scala Natura—The Great Chain of
Being.
• In Aristotle we see a division amongst the
animals by way of the kind of soul they
possess—nutritive, sensitive, rational.
• This is a hierarchical ordering.
The Scala Natura—The Great
Chain of Being
• For Aquinas, things were ordered in the world
according to their perfection and reflecting God’s
plan.
• Humans are close to the top of the chain of
being, with God at the very top.
• Everything has a purpose (teleology)—God is
the Final Cause of all in the world.
• The Great Chain of Being reflects God’s plan.
• Thus, the Aristotelian world-view is consistent
with Christianity.
The Scala Natura—The Great
Chain of Being
• This had an important influence on Taxonomy in
biology—e.g. the Three Kingdoms (animal,
vegetable and mineral) that made up Linnaeus’s
taxonomic system).
• The idea was still influential on Shakespeare
and up to 1667—Milton’s Paradise Lost.
• In fact, it is still present in some versions of
Christianity today—that God has a purpose for
all things—a master plan.
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The
Scientific
Revolution
Nicolas Copernicus (1473-1543)
Nicolas Copernicus
Nicolas Copernicus
• Up until Copernicus’ publication of On the
Revolutions of the Heavenly Bodies, the
Ptolemaic (90-168AD) model of the
universe was dominant theory.
• Ptolemy’s model was a detailed
mathematical account of the orbits of the
planets that was geocentric (earth at the
center).
• Aristotle also had a geocentric cosmology.
• Copernicus revolutionized the way we
viewed the planetary system by proposing
that the sun was the center of the (known)
universe—heliocentric model of the
universe.
• This upset a great deal of traditional
thinking.
• Cosmology was tied to the notion of the
Great Chain of Being.
Nicolas Copernicus
Francis Bacon (1561-1626)
• The Earth was the focus of God’s creation an as
such was held to be the center universe—God’s
plan.
• As such his view was rejected by the Church.
• But it inaugurated an enormous shift in our
thinking about the world.
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Francis Bacon
• Bacon ushered in a new way of thinking about how we
ought to go about understanding the world.
• It was the first articulation of the scientific method—in his
Novum Organon—a play on Aristotle’s Organon.
• Bacon was deeply critical of the ancients and challenged
the fundamental form of reasoning they used in the
acquisition of knowledge—the deductive method.
• He argued that there had been little progress to our
understanding of the world and that a reform was
required.
Francis Bacon
• In outline, this is an articulation of the
basic tenets of the scientific method—
observation, experimentation and
generalization.
Francis Bacon
• In the place of deduction, he argued for an
inductive method of inquiry.
• Scientific reasoning is still held to be a form of
inductive reasoning.
• The goal was, through experience, to collect
facts in an unbiased way.
• Then on the basis of an analysis of these facts
we proceed to make modest generalizations
about the nature of the world—inductive
generalizations!
Next Class
• Galileo, Descartes, Newton and the British
Empiricists.
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