3. He was a Greek philosopher and polymath. Also a
student of Plato and teacher of Alexander the
His writings cover many subjects,
including physics, metaphysics, poetry, theatre,
music, logic, rhetoric, linguistics,
politics, government, ethics, biology,
Aristotle's writings were the first to create a
comprehensive system of Western philosophy,
aesthetics, logic, science, politics,
4. Empiricism is a theory of knowledge which
states that knowledge comes only or
primarily from sensory experience.
Aristotle is an empiricist because he thinks
that all knowledge comes to human beings
from and through sensation. Our minds start
out as blank slates and from sensation we get
our ideas or the so-called "contents" of our
5. Metaphysics (questions related to existence)
Epistemology (questions related to
Logic (theory of correct reasoning)
6. Metaphysics is the branch of philosophy
concerned with the study of "first principles"
and "being" In other words, Metaphysics is
the study of the most general aspects of
reality, such as substance, identity, the nature
of the mind, and free will. It is a study of
nature and the nature of the world in which
7. Aristotle’s Metaphysics has as its central
theme on an inquiry into how substance may
be defined as a category of being. According
to Aristotle, the being of any individual thing
is primarily defined by what it is, i.e. by its
substance. Substance is both essence (form)
and substratum (matter), and may combine
form and matter.
8. kinds of causes of things:
the formal cause (the form of the thing)
the material cause (what it is made of)
the efficient cause (what made it)
and the final cause (its purpose or end).
9. Aristotle divided his Metaphysics into three parts
Ontology: The study of being and existence; includes
the definition and classification of entities, physical
or mental, the nature of their properties, and the
nature of change.
Theology: The study of a God or gods; involves many
topics, including among others the nature of religion
and the world, existence of the divine, questions
about Creation, and the numerous religious or
spiritual issues that concern humankind in general.
Universal science: The study of first principles, such
as the law of noncontradiction (logic), which Aristotle
believed were the foundation of all other inquiries.
10. Ethics, also known as moral philosophy, is a
branch of philosophy that involves
systematizing, defending and recommending
concepts of right and wrong conduct.
Aristotle considered ethics to be a practical
rather than theoretical study, i.e., one aimed
at becoming good and doing good rather
than knowing for its own sake.
11. Aristotle taught that virtue has to do with the
proper function of a thing. An eye is only a
good eye in so much as it can see, because
the proper function of an eye is sight.
Aristotle reasoned that humans must have a
function specific to humans, and that this
function must be an activity of the soul in
accordance with reason.
12. The term "logic" came from the Greek
word logos, which is sometimes translated as
"sentence", "discourse", "reason", "rule", and
logic as the study of the principles of correct
actually quite a controversial matter.
13. Aristotle was the first to systematically study and
catalogue the rules of correct logical reasoning
His logic is important because it dominated all
western thought, including scientific thought, until
the 19th century CE; it also had enormous influence
on the development of Jewish, Christian and
Muslim philosophy. It is still influential today.
Although other types of logical systems exist,
Aristotelian logic is still a powerful tool used to
teach reasoning skills in numerous academic
14. In his logic, Aristotle explicitly established three
laws of logical thought.
Law # 1: law of identity: “each thing is inseparable
from itself and its being one just meant this” A
thing is just itself and not something else: e.g. a
soccer ball is a soccer ball and not a kitchen
* Sometimes this is expressed as A = A.
Note: the fact that we can use a book for a doorstop does
not mean it is not a book. Its use does not contradict the
law of identity. What a thing is and how it is used are two
15. Law # 2: the law of contradiction: “the same
attribute cannot at the same time belong and not
belong to the same subject and in the same
respect” . E.g. my cup cannot be blue and not-
blue at the same time
•A cannot be A and not-A at the same time in the
Note: things may have and not have the same attributes in
different ways: e.g. man is the most intelligent creature
compared to animals but he is not intelligent compared to
God. So man is both intelligent (compared to animals) and
not intelligent (compared to God). There is no contradiction
because ‘intelligent’ is being used in different ways.
16. Law # 3: the law of the excluded middle or
excluded third : “there cannot be an intermediate
between two contradictories, but of one subject
we must either affirm or deny any one predicate
•A statement about a topic must either be true or
false. It cannot be both, i.e. there is no middle
between them. It cannot be neither true nor false.
• Note: It is either true that Socrates is mortal or it is not
true that he is not mortal. He is not both. Nor can he be
neither mortal nor immortal.
• Another example: It is either true that there is a rubber
duck in my bath tub or it is not true. Nor can we say neither
of these choices is true.
17. Epistemology is derived from the two Greek
words “episteme “knowledge and “logos”
science, and means the science of knowledge.
As employed in philosophy the word means
the science of the certitude of human
18. Aristotle defines soul as the Form of a natural
body that has the potential to possess life. This
body then must be furnished with organs: lungs,
stomach etc. Life then is the process of growth
Sensation requires an external stimulus, to move
the potentiality to an actuality. In this case, the
perceptive organ, i.e. the eye, is potentially what
the object is actually. When having a sensation,
the eye, which is only logically distinct from the
“seeing” of the eye, is one in quality with the
object of sight. So when looking at a green wall,
the eye becomes qualitatively green.