Department of History
University of California, Irvine
 Instructor:    Dr. Barbara J. Becker


Lecture 2.  Aristotle

Treatises Attributed to Aristotle (384-322 BCE)
Logic -- What, how and why of reason
  • Categories
  • On Interpretation
  • Prior and Posterior Analytics...
Inanimate things -- What, how and why of the material world
Animate things -- What, how and why of living things
Philosophy -- What, how and why of social interaction
  • Metaphysics
  • Ethics
  • Politics...

Aristotle's Critique of Plato

Postulating the existence of two worlds (Real and Ideal) --

  • does not resolve the Parmenidean conundrum
  • it only doubles the problem by giving us two ontological systems to explain

The Form (Idea, blueprint) of a thing (its user's manual for achieving its function, purpose or goal) --

  • is not an abstract representation that exists in some inaccessible thought-space
  • it is embedded in the thing's tangible natural world being....
The form of an oak resides in the acorn -- the future roots, trunk, branches, leaves and even acorns are all there:  all potential just waiting to be actualized.

Mathematics --

  • is not the sole path to scientific knowledge
  • is a model for reasoning, but is limited in its usefulness when applied to the natural world
  • is useful in gaining knowledge of the heavens, optics, perspective...
  • is not useful for investigating living things

Living things --

  • do not adhere to rigid patterns of behavior
  • require a new model for reasoning, one based on what is probable, not just what is certain
  • this kind of reasoning also is scientific (beautiful), as is the study of animals

Aristotle's Argument for Biology as a Scientific Study
excerpt from
Parts of Animals
(Book I, Chapter 5; compare this translation with William Ogle's)

Of things constituted by nature some are ungenerated, imperishable, eternal; others subject to generation and decay.  The former are excellent beyond compare and divine, but less accessible to knowledge.  The evidence that might throw light on them, and on the problems which we long to solve respecting them, is furnished but scantily by our senses.

On the other hand, we know much of the perishable plants and animals among which we dwell.  We may collect information concerning all their various kinds, if we but take the pains.

Yet each department has its own peculiar charm.  The excellence of celestial things causes our scanty conceptions of them to yield more pleasure than all our knowledge of the world in which we live; just as a mere glimpse of those we love is more to us than the grandest vista.  On the other side we may set the certitude and completeness of our knowledge of earthly things.  Their nearness and their affinity to us may well balance the loftier interest of the things of heaven, that are the object of high philosophy.

But of a truth every realm of nature is marvellous.  It is told that strangers, visiting Heraclitus and finding him by the kitchen fire, hesitated to enter.  "Come in, come in," he cried, "there are gods even here."

So we should venture on the study of every kind of creature without horror, for each and all will reveal something that is natural and therefore beautiful.  Absence of haphazard and conduciveness of all things to an end are ever to be found in nature's works.  And her manner of generating and combining in ever changing variety is of the highest form of the Beautiful.

If any person thinks the examination of the rest of the animal kingdom an unworthy task, he must hold in like disesteem the study of man. For no one can look at ... blood, flesh, bones, [and] vessels ... without much repugnance....  Moreover, when any one of the parts or structures ... is under discussion, it must not be supposed that it is its material composition to which attention is being directed ... but the relation of such part to the total form....

[T]he true object of architecture is not bricks, mortar, or timber, but the house; and so the principal object of natural philosophy is not the material elements, but their composition, and the totality of the form, independently of which they have no existence.

Fundamentals of Aristotle's Natural Philosophy
All matter is made of two parts:

    hyle (HOO-lee)--basic fundamental stuff
    qualities--characteristics superimposed on hyle

Terrestrial Elements
Cold and Dry
Cold and Wet
Warm and Wet
Warm and Dry

Tension and balance generated by opposing qualities (wet vs. dry; cold vs. warm) is behind all change observed in terrestrial world.

Celestial Element
Quintessence, or aether
Arché motion (not a material substance)
    • change of state (growth, decay, death, size, shape...)
    • change of position
Physis opposition
    • cold vs hot
    • wet vs dry

Physics of the Celestial realm

The celestial element (quintessence) has no opposing qualities.

  • quintessence is perfect and immutable 
  • a celestial body moves forever according to its perfect nature in a perfect circle at constant speed 
  • any sensory evidence to the contrary is illusory

Physics of the Terrestrial realm

Each terrestrial element (earth, water, air, fire) has a natural place or state.

  • some amount of each element is present in every body
  • therefore, opposing qualities are always at work
  • if a body (animate or inanimate) is removed from the natural place or state of its predominant element (violent change), it will naturally strive to return where it belongs (natural change)
  • if a body's natural qualities become imbalanced (violent change), it will naturally seek a more suitable place or state for itself given its new nature (natural change)

An animate body is constantly appropriating and organizing resources from its environment in order to actualize its potential as defined by its Form.

It must become what it is to be.

To know a thing is to understand four basic things which cause it to be as it is:

material cause ingredients what a thing is made of
[table: wood, glue, nails...]
[tree: wood, sap, leaves...]
[human: flesh, blood, bones...]
formal cause blueprint pattern into which it fits
[table: stable legs supporting a sturdy flat surface]
[tree: root structure; trunk; branches...]
[human: symmetrically arranged limbs, trunk, head...]
efficient cause instructions how it is made, or happens
[table: carpenter; tools; physical labor]
[tree: seed; gardener; planting]
[human: sperm; father; copulation]
final cause purpose why it is made; its purpose
[table: to provide a space for working, eating, storing...]
[tree: to offer shade, fruit, nesting space for birds...]
[human: to sense; to reason; to reproduce...]
Aristotle's Definition of Life
excerpt from
On the Soul
(Book II, Chapter 2; compare this translation with J. A. Smith's)
The term life is used in various senses. If life be present in but a single one of these senses, we speak of a thing as alive. Thus, there is intellect, sensation, motion from place to place and rest, the activity concerned with nutrition, and the processes of decay and growth.

Plants have life, for they have within themselves a faculty whereby they grow and decay. They grow and live so long as they are capable of absorbing nutriment.

In virtue of this principle [the vegetative soul] all living things live, whether animals or plants, but it is sensation which primarily constitutes the animal and justifies us in speaking of an animal soul. For, provided they have sensation, creatures, even if incapable of movement, are called animals....

Aristotle's Classification of Animals
based on his History of Animals
Things without Soul
All potential, no actuality, inanimate
Things with Soul
Lower Plants
Jellyfish           Sponges
Higher Plants
Jointed Shellfish
Octopuses and Squids
Reptiles and Fish
Theophrastus (c. 372 - 287 BCE)
On Aristotle's death in 322 BCE, his student, colleague and friend, Theophrastus took charge of the Lyceum, Aristotle's school in Athens.  He wrote lengthy and detailed treatises on plants.  His efforts at categorizing the plants he observed and recorded earned him the title of "father of taxonomy."  His treatise, On Stones, influenced the thinking of natural historians, medical practitioners, and miners well into the Renaissance.
Hellenistic Period (323-31 BCE)
  • Greek language and culture spread throughout the known world
  • Commerce became international
  • Greek learning influenced by Babylonian science
  • Museum established in Alexandria
    • intellectual center of known world
    • literature, mathematics, astronomy, medicine
    • library containing over 400,000 scrolls
The Alexandrians
(Hellenistic Period--Greek influence)
Euclid 330-260 BCE Mathematics
·wrote The Elements
Aristarchos 310-230 Astronomy
Archimedes 287-212 Engineering
Eratosthenes 276-194 Math/Astronomy
·librarian at Alexandrian Museum
·measured size of earth
Hipparchus 190-120 Astronomy
·mapped the heavens
·studied Babylonian records
·discovered Earth's precession

(Roman Empire--Greeks)

Hero fl. 62 CE Optics
· studied reflection and refraction
· constructed automated gadgets
Ptolemy fl. 125 Astronomy/Cartography
· wrote Almagest; The Geography
Galen 131-201 Medicine
· wrote On the Natural Faculties
Go to:
  • "Vulcan's Marvels," from The Iliad, Book XVIII (6th c. BCE?) attributed to Homer (?)
Readings for Week
Lecture Notes for