Main characteristics of Aristotle's thought

1. Aristotle
Stagira 384 B.C. – Chalcis 322 B.C.

2. Life
:Aristotle was born in Stagira in 384 B.C. When he was 17 years old he went to Athens
and entered the Plato’s Academy; he attended Plato’s school for twenty years
(however , Aristotle’s philosophy differs from the one of Plato).
Then, Philip II of Macedon invited him to become Alexander’s (his son, then called ‘the
Great’) tutor. Because of being Alexander’s teacher, Aristotle got big economical
resources with which he opened a school in Athens, called ‘Lyceum’.
Alexander’s death forced him to run away (an anti-Macedonian sentiment was spreading
in Athens) to Chalcis, where he died in 322 B.C.
Raphael: The school of
Athens;
On the left: Plato
On the right: Aristotle

4. Aristotle’s writing are divisible in two groups:
• Esoteric works: directed to his pupils
•Exoterics works : popular works, directed to
people who didn’t study in his Lyceum
His writings are about:
• Logic
• Metaphysics
• Physics
• Psychology
• Ethics, politics, rhetoric and poetics

5. Metaphysics
• also called‘first philosophy’; it’s the knowledge of
immaterial being. It studies the being in general.
Aristotle wondered: what is the being?
He thought that the being can’t be defined in a single way,
because it has a multiplicity of meanings. Among this the
most importants are:
1. The being as accident
2. The being as truth
3. The being as action and ability
4. The being as categories

6. Aristotle and the
categories
The categories, in Aristotle’s opinion, are the fundamental and structural
caracteristic of the being. They are:
 SUBSTANCE
 QUALITY
 QUANTITY
 RELATION
 TO ACT
 TO SUFFER
 PLACE
 TIME
 TO OWN
 TO LIE
The most important category is, however, the one of
substance and the others refer to it. Substance is
what is and keep being, what lasts and doesn’t
change. The substance is characterized by three
principles:

7. 1.No
contradiction:A can‟t be different from A. There‟s no
possibility that an object different
from A has the same properties of A
2.
Identity
3. Tertium non
datur
A=A
Every object is equal to
itself.
To know the reality we need to know the causes
of events. There are four types of cause in a
event:
1. Material
2. Formal
3. Final
4. Efficient

8. Aristotle also classifies the
knowledge:
knowledg
e
theoretic
al
practica
l
poetical
art
technique
ethics
politics
metaphysics
physics
maths
They study what is
necessary, what is in a
certain way and can‟t
be different
They study and
represent what is
optional and
possible, but not
essential
Ex: 1. A triangle, to be so, must have three angles and three sides. (NECESSARY)
2. Dante wrote: ‘Nel mezzo del cammin di nostra vita..’, but he could have written this in a
different way or could haven’t written it at all. (OPTIONAL)

9. Logic
Aristotle is also considered the founder of logic, which is the theory of
reasoning; the science of valid reasoning. The logic is formal, like maths,
for it has to be valid for everyone.
A = B
B = C
A = C Classic example of logic reasoning,
universally acknowledged
He differentiates in a concept:
Intension: word which is used by Aristotle as synonymous of
comprehension; fundamental characteristic that joins things present in the
group of extension
Extension: number of element which are joined in the group of
intension
“Intension is inversely proportional to
extension”
(called by Aristotle „organon‟: the fundamental vehicle of
phylosophy)

10. ARISTOTLE ALSO DIFFERENTIATES BETWEEN
REASONING:
Inductive: Deductive:
≠particular general general particular
example: induction
1. Almost all people are taller than 1.40 metres
2. Sally is a person
3. Sally is almost certainly taller than 1.40 metres
example: deduction
1. All men are mortal
2. Aristotle is a man
3. therefore, Aristotle is mortal Me
n Aristotle

11. When Aristotle talks about reasoning he refers to syllogist reasoning which is the
deduction had from the union of two sentences.
We can have a syllogism only if in the two sentences there’s a middle term, a term in
common. No deduction if there’s not any middle term.
The syllogism consists of three parts:
1. Major premise All men are mortal
2. Minor premise Socrates is a man
3. Conclusion Socrates is mortal
There can be four types of syllogism:
M=middle term
P= predicate
S= subject

12. *What kind of sentence can we
have in our reasoning?We can have four kinds of different sentence
1.Universal and affermative = A
Every man is mortal
2. Universal and negative = E
No man is mortal
3. Particular and affermative = I
Some men are mortal
4. Particular and negative = O
Some men are not mortal

13. square of
opposition
A and E are contraries: they’re quantitatively equals but qualitatively differents; one
of them may be true
E and I/ A and O are contradictories: quantitatively differents; one excludes the
other
I and O are subcontraries: quantitatively equals, they both can be true, because,
though partially contraries, they don’t exclude each other.
A and I/ E and O are subalterns: they don’t contradict each other because I and O
are included in A and E
A
D
F
I
R
M
O
N
E
G
O
Omne S est P Nullum S est P
Quoddam S est
P
Quoddam S non est P

14. Phys
icsAristotle‟s physiscs was the official science until Galileo.
He distinguishes between the the physics of:
TERRESTRIAL BODIES which are subject to changes; they‟re imperfect and made up of the four elements
(air, water, fire, soil)
CELESTIAL BODIES considered perfect by Aristotle; they‟re not subject to any change and are made of
the fifth essence (called „etere‟). The quintessence is conceived as a divine and perfect element which
is similar to the air (as physic state)
The movement of celestial bodies is perfectly circular
The one of the terrestrial bodies is only vertical because the
movement of the four elements can be only perpendicular, and
Aristotle said that by observing some event:

15. The air in the water shapes some
bubbles, so there’s a vertical
movement.
When we pour some
water in a glass we can
see that it falls down.

16. By observing the fire
you can see that it
goes up
If you put some soil in
a receptacle of water,
you’ll see that the soil
settle on the bottom.

17. Aristotle was also interested in the fall of bodies
He thought that
• the velocity of the fall was directly proportional to
its weigh; he didn’t acknowledge the existence of the
vacuum.
• the earth doesn’t move, because if it did:
1. It would be windy all the time
2. The fall of bodies wouldn’t be vertical
3. Birds wouldn’t arrive to their destination
In Aristotle‟s opinion:
F=mv
Second law of motion
(Newton‟s):
F=ma

18. In his writing of physics, Aristotle talks about becoming
meant as movement and change.
Aristotle defines the becoming as a transfer from the power to the deed.
Capacity of substance
to assume another form Fulfillment of
the power
Nicole Montis 3^E