Transcript Slide 1

Epistemology and
Faith and Reason
MAYMESTER 2007
DAY 4
Rationalism
The main option to Empiricism is called
Rationalism
We will consider the rationalism of Descartes.
Read: Rauhut on Rationalism
Read: Descartes Discourse on Method Part 4
<http://www.earlymoderntexts.com/pdfbits/dd34.pdf>
Rationalism vs. Empiricism
Rationalists think that they can know about
REALITY by employing reason alone (i.e.
there are parts of reality knowable by
reason alone)…
Empiricists think that everything knowable
is known through the senses, and the
objects that motivate the rationalists are
really products of the mind (Hume’s
relations of ideas)
Rationalism (2)
Historically Rationalism has been associated with
figures such as:
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Plato – (Theory of Forms/Recollection)
Descartes – (Cogito/Clear and Distinct)
Spinoza – (More Geometrico)
Leibniz – (Truths of Reason)
Rationalism (3)
Making sense of Rationalism is difficult sometimes.
Rationalism usually emerges from either
1) Thinking that knowledge has a special status
(indubitable, innate, necessary)
2) Thinking that there are special objects of
knowledge (forms, necessary truths, numbers)
Different Rationalists emphasize these to different
degrees
Rationalism Defined
Rationalism =
Our fundamental knowledge of the
universe is provided by reason
Most Rationalists also admit that the senses
can color our rational knowledge, but that
the outlines are given by reason alone.
The main idea!
Rationalists (usually) do not reject sensory
perceptions, but…
They hold that either:
1) Knowledge is fixed and unchanging –
whereas the world of the sense is
changing, or…
2) (At least some) Objects of knowledge are
not given to the senses.
Unchanging Knowledge
Plato thought that knowledge required that the
state of knowing be such that if you know P
that cannot ever change.
The empirical world is limited and constantly
changing
So, we cannot have empirical knowledge—only
belief
Thus, if we have knowledge, it is not obtained
empirically – Plato thus adopts innate ideas
as the source of human knowledge
Special Objects of Knowledge
Plato’s Forms – Special Ideal Objects
Descartes/Leibniz:
Necessary Truths – Truths of Reason
How do we know them?:
Innate Ideas
Self-Evidence (C&D, Impossible to deny)
The Rationalism of Descartes
Descartes used the Principle of Hyperbolic
Doubt to limit what counts as knowledge to
those things which cannot be doubted.
His “foundation” for knowledge is:
Cogito ergo sum ; I think therefore I am.
Descartes: Cogito
• The “Cogito” is the claim that I cannot
doubt that there is doubt.
• If there is doubt, then there is thought
• If there is thought, then there is a
thinker.
• SO, if I doubt, then I think
• If I think, then I exist
• Thus, if I doubt, then I exist.
Descartes: Clear and Distinct
Ideas
• According to Descartes, the distinguishing
characteristic of the Cogito is that it is
“CLEAR AND DISTINCT” (CD)
• So, Descartes reasons that if a belief B is
CD, and God is not deceiving me, then I
know B is true, so I know B.
• The truths of Logic, Mathematics, and
Geometry are CD
• So are primitive sensory experiences (like
Hume’s impressions)
Descartes: Rebuilding Knowledge
Descartes argues that if God exists, then we
know that there is no Evil Demon
deceiving us.
The first step in reconstructing knowledge is
to prove that God exists. (We will get to
that later)
Rebuilding knowledge
Once this is done, then Descartes can start
to rebuild human knowledge by
constructing an experienced world out of
geometry and sense data.
Truths about this world, the world of science,
can be known by reason alone.
Rationalist examples
The idea of God.
R: I have an idea of God, but I cannot get it
through the senses.
E: You can make an idea of God using abstraction
and imagination
R: OK, but why do we all make basically the same
idea of God???
Rationalist examples (2)
The Pythagorean Theorem:
R: for all right triangles A2 + B2 = C2
E: I can discover this by trial and error, and others
can confirm it.
R: OK, but I said “for all” not “for all up until now”
There is a difference! I know that the theorem
will hold in cases not yet tried, you don’t.
Rationalist Justification
A Rationalist might say:
A Belief in P is justified just in case P is a
neccesary truth, or is deducible from a
necessary truth.
Empiricists tend to be inductive reasoners
Rationalists tend to be deductive reasoners
Leibniz vs. Hume
(Some similarities)
Leibniz (a rationalist/nativist) distinguishes
between:
Truths of Fact (truths about the world)
Truths of Reason (truths about ideas)
Hume (an empiricist) distinguishes between:
Matters of Fact (what we know in experience)
Relations of Ideas (what we know about ideas)
Four Kinds of Knowledge? (Kant)
A Priori
All Squares have
Analytic
(Relations of Idea) 4 sides.
(Truths of Reason) All fathers are
A Posteriori
NO NEED
male.
Synthetic
(Matters of Fact)
(Truths of Fact)
2 + 2 = 4 (?)
2 + 2 = 4 (?)
Tom is 6 ft tall.
It is 68 degrees
outside.
Knowledge as Justified True Belief
If Knowledge is Justified True Belief, then
a) Empiricist knowledge is true belief that is
obtained through reliable sense
experience.
b) Rationalist knowledge is true belief that
is either necessary, deducible from a
necessary truth, or innate.
A Summary of sorts…
View
K. is
Possible
K. Can be
had by
reason alone
K. is innate
K. Comes from the
senses
NO
_
_
_
Empiricism
YES
NO
NO
YES
Rationalism
YES
YES
Some
times
Sometimes
(must also
use reason)
Skepticism
Philosophy of Religion Slides
2006
© Robert Barnard 2006
Philosophy and Religion
Historically Philosophy and Religion have
been closely related.
Classical and Medieval Philosophers were
often also religious thinkers or theologians
Augustine, Anslem, Aquinas, Plotinus,
Duns Scotus, William Ockham, etc.
Some Issues in the Philosophical
Approach to Religion:
1. Analysis of Religious Concepts
2. The role of Faith vs. Reason in Religion
Is Belief Rational?
3. How we can know God/Religious Truths
(Religious Epistemology)
4. The existence of God
Proofs for God
…by Faith alone?
• Tertullian – Credo Quia Absurdum
“I believe because it is absurd”
• Kierkegaard – “The Leap of Faith”
But what do they believe?
And, how should we understand them?
Stances toward ‘God’
• THEISM – Affirms that God exists.
• ATHEISM – Denies that God exists.
• AGNOSTICISM – Neither affirms nor
denies the existence of God. (Usually
wants more evidence or a proof)
What do we mean by God?
We can use a single word to denote many
ideas or objects.
Do we all mean the same thing by “God”?
What is God like?
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IS GOD ETERNAL?
DOES GOD KNOW THE FUTURE?
IS GOD MALE OR FEMALE (OR SEXLESS)?
DOES GOD HAVE A PHYSICAL BODY?
IS GOD ALL POWERFUL (OMNIPOTENT)?
IS GOD ALL KNOWING (OMNISCIENT)?
IS GOD ALL-GOOD (OMNIBENEVOLENT)?
IS GOD THE GREATEST CONCIEVABLE
BEING?
• ARE GOD AND JESUS THE SAME PERSON?
• IS GOD EVERYWHERE (OMNIPRESENT)?
(After Rauhut, p. 172)
What is God like? (Part 2)
• DOES GOD HELP THOSE IN NEED?
• DOES GOD CAUSE MIRACLES?
• DOES GOD GET MAD AT HUMANS AND
PUNISH THEM?
• DOES GOD LOVE ALL HUMAN EQUALLY?
• IS GOD SO DIFFERENT FROM US THAT WE
HAVE NO CONCEPTION OF GOD?
• IS GOD INFINITE?
• DOES GOD HEAR YOU WHEN YOU SPEAK
TO GOD?
• IS THERE ONE GOD OR MANY?
(After Rauhut, p. 172)
Varieties of Theism
• Classical Theism – Judaism,
Christianity, Islam
• Pantheism – Shinto, Hinduism
• Pan-en-theism “everything is a divinity”
• New Age Theism
• Dualism – Zoroastrianism /
Manicheanism
Classical Theism
According to Classical Theism:
• God is a Person / Agent.
• God is capable of thought, desire,
creativity, emotion.
• God acts in the world and can be in
relations with humans.
The “Classical” Picture
GOD IS (at least):
Omnipotent
Omniscient
Omnibenevolent
Omnipresent
Rational
Eternal
Arguments for Theism
• Arguments for the existence of God
If God exists, then denying God is embracing a
falsehood
• Arguments for the rationality of belief in God.
Despite the fact that we cannot directly
demonstrate the existence of God, there are still
reasons to believe rather than remain agnostic.
Arguments for the existence of God
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Argument from Religious Experience
Cosmological Argument
Design Arguments
Ontological Arguments
Argument from Religious
Experience
1. I have experiences that seem to be
caused by God.
2. Every effect has a cause.
-------------------------------------3. Therefore, God Exists.
Argument from Religious
Experience (2)
Is the Inference Valid?
1. I have experiences that seem to be
caused by the Easter Bunny
2. Every effect has a cause
-------------------------------------------3. Therefore, the Easter Bunny exists
Is this a counter-example? (too external?)
Argument from Religious Experience (3)
1. I have experiences that seem to be caused by
a monster in my closet
2. Every effect has a cause.
------------------------------------------3. Therefore there is a monster in my closet.
There are other possible causes of the
experiences
Calling them Religious experiences is prejudicial
Cosmological Arguments
• In General, a COSMOLOGICAL argument
argues from the fact that the world exists
or has certain general features to the
conclusion that GOD’s Existence is
necessary to explain these facts.
• Aristotle and Aquinas are well known for
making Cosmological Arguments of this
kind.
Cosmological Arguments (2)
• The Key Assumption:
The Principle of Sufficient Reason:
For every event or object that exists there
must be an explanation for that event or
object.
Cosmological Arguments (3)
1. The Cosmos Exists (Observation)
2. There must be a reason for the existence
of the Cosmos (PSR)
3. It is possible that the cosmos didn’t exist,
so its cause must be necessary.
4. SO, if the cosmos exists a necessary
being exists.
(1st conclusion)
5. God is that necessary being (definition?)
6. Therefore, God (necessarily) exists.
Cosmological Arguments (4)
•
This version of the CA depends upon
premise (3) that the cause of the
universe is necessary.
To get (3) you must eliminate two
possibilities
1. The cosmos is caused by a contingent
physical event (e.g. Big Bang)
2. The cosmos itself exists necessarily
(Brute Fact view)
Cosmological Arguments (5)
Possible Prima Facie replies:
1. If the cosmos was caused by the big bang,
what caused the big bang? – causal regress is
extended
2. If the existence of the universe is necessary by
itself, why is that so?
- Do we reject PSR? (Ad Hoc, we still apply it
in other places)
- Why does the necessary universe have these
features and not others? (feeds the design
argument)
Cosmological Arguments (6)
Worries about the CA
1. CA assumes PSR
2. CA assumes that the cosmos is contingent (not
a brute fact)
3. CA assumes that God is the only possible
necessary being (must a necessary being be
God?)
4. Doesn’t rule out plural necessary beings
Conclusion: CA is not definitive
Next Time
The Argument from Design
The Ontological Argument
The Rationality of Theism
-andThe Problem of Evil
Read: Rauhut Chapter 7
Read: Descartes Meditations Meditation 3
(Reading: Http://www.earlymoderntexts.com/pdfbits/dm3.pdf )