1.
Methods of
Philosophy
J O U R N E Y T O
T R U T H
An Introduction to the Philosophy of
the Human Person
Prepared by:
WILFREDO DJ P. MARTIN IV | SHS SETA

2.
Is Opinion
Knowledge
?

3.
Jens
Martensson
Doxa and Episteme
Understanding Opinion and Knowledge
► There is a variety of sources whenever views
are discussed.
► Illusions should then be distinguished from
what is reality.
► When we talk about knowledge (episteme),
we are not concerned with mere belief or
opinion (doxa).
► To know then is to be able to give rational
justification

4.
Jens
Martensson
P L AT O
Ancient Roots
Plato’s Views on Knowledge and Opinion
► He was often considered as the first to
differentiate knowledge from opinion.
► For him, knowledge is certain whereas
opinion is uncertain.
■ We remain ignorant when we rely on opinions for
they are based on appearance and not reality.
■ Appearances are unreliable and deceptive
► His dialogues are activities directed toward
discovering truths and acquiring knowledge.
► He performed dialectics as learned from his
teacher Socrates.

5.
Jens
Martensson
A R I ST OT L E
Ancient Roots
Aristotle’s Syllogism
► In demonstrating truth claim and opinion he
developed SYLLOGISM: .
► A systematic representation of a single
logical inference. It has three parts: a major
premise, a minor premise, and a conclusion.
The parts are defined this way:.
■ The major premise contains a term from
the predicate of the conclusion
■ The minor premise contains a term from
the subject of the conclusion
■ The conclusion combines major and minor premise
with a “therefore” symbol (∴)
► When all the premises are true and the
syllogism is correctly constructed, a
syllogism is an ironclad logical argument..

6.
Jens
Martensson
Syllogism
► The most famous syllogism in
philosophy is this:
■ All men are mortal (major premise)
■ Socrates is a man (minor premise)
■ ∴Socrates is mortal (conclusion)
► Notice that the major premise
provides the predicate, while the
minor premise provides the
subject. As long as both premises
are true, the conclusion must be
true as well.

7.
Jens
Martensson
Syllogism
► That first syllogism was pretty easy, since
no one would ever argue with its
premises. But syllogisms become more
difficult when the premises are more
complicated or debatable. For example:
■ Cats make good pets (major premise)
■ Dogs and cats are equally good as pets (minor
premise)
■ ∴ dogs make good pets (conclusion)
► Is this argument true? It depends! Some people might disagree
with the premises, or with the conclusion. It’s a matter of
opinion. However, the logical validity of the syllogism is not a
matter of opinion, because the conclusion really does follow
from the premises.That is, if the premises are true, then the
conclusion must be true as well.That makes it a logically valid
syllogism regardless of whether or not you agree with the
premises or the conclusion!

8.
Jens
Martensson
Syllogism
► You can also have cases where a
syllogism is logically sound,
but factually incorrect. For
example:
■ This car is expensive (minor premise)
■ All expensive cars are Ferraris. (major
premise)
■ ∴ this car is a Ferrari. (conclusion)
► The major premise in this syllogism, of course,
is wrong. In terms of its logical structure, there’s
nothing wrong with the syllogism. But it’s based on a
faulty assumption, and therefore the argument
doesn’t work. If the major premise were true, then
the conclusion would follow, which means the
syllogism is perfectly logical. It just so happens that
the premise isn’t true.

9.
Jens
Martensson
R e n e D e s c a r t e s
Modern Legacy
DesCartes’ Views on Knowledge and Opinion
► He is considered as the Father of Modern
Philosophy.
► For him, statements that are false, doubtful,
or uncertain cannot be used as basis for
knowledge.
► Dubito, ergo cogito, ergo sum.
► Clear and distinct ideas alone can become the
foundation of all knowledge.
► Opinions are those that can be doubted and
their lack of clarity makes them dubious
whereas Knowledge is indubitable hence,
certain.

10.
Jens
Martensson
J a c q u e s D e r r I d a
Contemporary Period
Derrida’s Views on Knowledge and Opinion
► He developed the theory of deconstruction.
► For him, non-essential elements or
appearances is the basis of everything that
can be spoken or written. (opposing Plato’s
concept of essence as knowledge)
► Derrida's approach consisted of conducting
readings of texts looking for things that run
counter to the intended meaning or
structural unity of a particular text. Clear and
distinct ideas alone can become the
foundation of all knowledge.
► The purpose of deconstruction is to show
that the usage of language in a given text,
and language as a whole, are irreducibly
complex, unstable, or impossible.

11.
Jens
Martensson
Questions of
Truth and
Opinion
Understanding Correspondence
Theory, LinguisticTurn,
Phenomenology and Existentialism

12.
Jens
Martensson
Correspondence Theory
► An idea is true if and only if it corresponds to
the facts or events of the world
► The truth or falsity of a statement is
determined only by how it relates to the
world and whether it accurately describes
that world.
► For example, "A cat is on a mat" is true if,
and only if, there is in the world a cat and a
mat and the cat is related to the mat by
virtue of being on it.

13.
Jens
Martensson
Linguistic Term
Context Principle
► According to this principle, it is only in the
context of a sentence that a word has
meaning.
■ Sense- the meaning (connotation)
■ Reference- the extension (denotation)
► For example, the sense of “The Solar System
is four billion years old” is different from “The
Solar System is in existence for billions of
years”
► Thus, the meaning of any given word (truth)
must be derived from the context of whole
sentences.

14.
Jens
Martensson
Phenomenology
► The study of structures of experience, or
consciousness. Literally, phenomenology is
the study of “phenomena”: appearances of
things, or things as they appear in our
experience, or the ways we experience
things, thus the meanings things have in our
experience.
► Studies conscious experience as experienced
from the subjective or first person point of
view.
► Experience is directed toward—represents or
“intends”—things only through particular
concepts, thoughts, ideas, images, etc.These
make up the meaning or content of a given
experience, and are distinct from the things
they present or mean.

15.
Jens
Martensson
► Existentialism is a European philosophy that
started in the mid-1800s and hit its stride in the
years aroundWorld War II. It has two parts:
► Life has no inherent meaning. Nothing we do
matters in an absolute sense.There is no God,
no objective morality, and no cosmic “purpose”
in life.
► That’s OK. Or even better than okay, because it
means that life can have the meaning that we
give it—that we are more important than any
pre-conceived notions about our lives.

16.
Jens
Martensson
► If you have only the first part and not the
second, you’d be considered a nihilist; with
both parts, you become an existentialist.The
reason it’s called existentialism is the idea that
our actual existence—what we’re doing or
experiencing at any given moment, is primary,
rather than some absolute reality, like god,
behind the scenes. So, existentialism is a
positive alternative to nihilism. Existentialism
also grew out of phenomenology, a philosophy
which attempted to make a new firmer
foundation for philosophy by only making
statements about what you know to be true,
100%, without a doubt, which turns out to
be only that you are having such-and-such an
experience, right now.

17.
Jens
Martensson
► phenomenologists strongly justified the idea
that your individual experience here and now is
more real than any gods or abstract ideals.
► So, existentialists focus on individual
experience and freedom; for existentialists, it’s
OK that the universe has no inherent meaning,
because that leaves us free to create our own
meanings, which are more real, and may even
turn out to be more beautiful and inspiring than
the old universal certainties of religion and
traditional philosophy. On the other hand, the
risks are considerable; if meaning in life is
entirely up to us, then what do we say to
people who make their meaning by harming
others?
►

18.
Thank
You