Benedict de Spinoza (1632-1677)
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Defends a monistic
metaphysics in which God
and Nature are identified.
God is no longer the
transcendent creator of the
universe who rules it via
providence, but Nature itself,
understood as an infinite,
necessary, and fully
deterministic system of
which humans are a part.
Humans find happiness only
through a rational
understanding of this system
and their place within it.
Baruch Spinoza
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Method: Begin with
self-evident
metaphysical truths
and deduce
theorems implied
implied by those
truths, producing an
absolutely certain
science of reality.
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…[T]here cannot be
conceived one
substance different
from another,- that is,
there cannot be several
substances, but one
only.
Extension and
consciousness are
modes of one infinite
substance, God.
G.W. Leibniz July 1, 1646 –
November 14, 1716
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Mathematician and
philosopher.
There are also two kinds of
truths: truth of reasoning
and truths of fact. Truths of
reasoning are necessary and
their opposite is impossible;
those of fact are contingent
and their opposite is
possible.
Leibniz
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The concept of extension is derivative, the building
blocks of reality are psychic particles, monads.
Extension is a property of a collection of particles,
each of which is unextended.
Each monad is designed by God to mirror the
universe. They do not interact causally, but a preestablished harmony governs their behavior.
A human is composed of monads, the chief of which
is the soul.
Principle of sufficient reason. This is the best of all
possible worlds.
An Essay Concerning Human Understanding (1690)
John Locke’s Empiricism
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If by this inquiry into the
nature of the understanding,
I can discover the powers
thereof; how far they
reach;…and where they fail
us, I suppose it may be of
use with the busy mind of
man, to be more cautious in
meddling with things
exceeding its
comprehension; to stop
when it is at the utmost
extent of its tether; and to
sit down in quiet
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ignorance of those things,
which, upon Examination,
are found beyond the reach
of our Capacities.
To ask, at what time a man
has first any ideas, is to ask,
when he begins to perceive;
having ideas and perception
being the same things.
He that would not deceive
himself ought to build his
hypothesis on matter of fact.
Locke’s Causal Theory of Perception,
Truth, and Knowledge
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The perception of external objects and
events causes images (ideas) in the
mind; reflection on how the mind
responds to this data causes ideas of
another sort (belief, hope, fear).
A tabula rasa (without innate ideas)
acquires and sorts images, creates
abstractions, and utters propositions.
The Production of Ideas
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An apple has qualities
that produce the simple
ideas of red, sweet,
crisp; from which we
form the complex idea
of apple, which, when
compared with other
ideas, gives rise to even
more abstract ideas of
fruit, taste, and
nutrition.
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Only primary qualities
(extension, number,
figure, motion, solidity)
are real, inseparable
properties of objects.
Secondary qualities
(color, taste, smell,
sound) are produced in
our minds but do not
really exist out there.
Options in Modern Philosophy
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Dualism (Descartes)
Materialism (Locke*)
Occasionalism (Malebranche)
Idealism (Berkeley): Esse est percipi;
to be is to be perceived. There is no
such thing as (what philosophers call)
material substance.
The materialist world view.
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Physical objects
would continue to
exist even if there
were no minds.
Physical objects
cause ideas to arise
in our minds.
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Physical objects have
primary qualities and
secondary qualities.
It is impossible to prove
beyond all doubt that
the physical world
exists. Skepticism is
irrefutable (but it may
be ignored)
George Berkeley (1685-1753)
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My endeavors tend only to unite, and place in
a clearer light, that truth which was before
shared between the vulgar and the
philosophers: the former [holding] that those
things they immediately perceive are the real
things; and the latter that the things
immediately perceived, are ideas which exist
only in the mind. Which two notions put
together constitute...what I advance.
Idealism
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Things we call
substances are
really just collections
of ideas which
depend for their
existence on the
mind. Reality is a
community of
spirits.
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We perceive ideas,
so if we perceive
objects, objects are
ideas. If they
weren’t ideas, we
couldn’t perceive
them. Since ideas
are mind dependent,
so must objects be.
Refutation of Secondary
Quality Realism.
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Intense heat = pain. Pain is minddependent. \ Intense heat is minddependent.
Place cold left hand and warm right
hand in water. Is the water cool or
warm?
Reducing sound to vibrations implies
that sound is not heard.
Against Primary Quality
Realism
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Red and purple sunsetis the color in the
clouds? What is the
real color? Sunlight?
candlelight? Under the
microscope? Reducing
color to matter and
motion makes real color
invisible.
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Perceptual relativity
affects primary quality
perception as well.
How large is a Perseae
mite’s foot?
To a mite----medium.
To us------ tiny.
To a Sub-mite---HUGE!
David Hume (1711-1776)
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We find in our minds
impressions (direct
sensations) and ideas
(copies of impressions).
Meaningful ideas can be
traced back to the
impressions that
produced them. Ideas
without impressions are
meaningless (e.g.
substance, self, cause).
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Legitimate ideas refer
either to relations
among ideas (math,
logic) or to matters of
fact (always possibly
false).
The gazing populace
receive greedily,
without examination,
whatever soothes
superstition, and
promotes wonder.
Cause and effect.
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Reasoning about matters of fact assumes
causal connections. But there are no
impressions of causality. Sensation discovers
only constant conjunction of event pairs (fire,
heat). Hence, custom or habit (not
knowledge) is the source of our belief in
causal connections. Experience only teaches us
how one event constantly follows another, without
instructing us in the secret connexion which binds
them together.
Immanuel Kant (1724-1804)
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What has hitherto been called metaphysics
cannot satisfy any critical mind, but to forego
it completely is impossible; therefore, a
critique of pure reason must be attempted.
All knowledge begins with experience, but not
all knowledge arises out of experience.
Impressions supplied by sensation are
structured by cognition. A Copernican
revolution in Philosophy.
Is Synthetic apriori knowledge
possible?
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Analytic statements:
Content of the predicate
is contained in the
subject. (Nuns are
female)
Synthetic statements:
Content of the predicate
goes beyond content of
the subject. (Nuns are
nice)
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Apriori knowledge:
Independent of sense
experience.
Aposteriori knowledge:
Dependent on sense
experience.
Noumena: Perceiver
independent reality.
Phenomena: Reality as
it appears to us.
Midterm Review
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Pt I. Matching. Match the
philosopher with his quote:
Thales, Democritus,
Parmenides, Heraclitus (wk
1),Socrates (wk 2), Aquinas,
(wk 3) Hume, Mill, Pascal,
James (wk 4)
Part II. Short answer.
1.Objection to piety definition
(Euthyphro)(2)
2. The Socratic Mission (2)
3.James- skeptical balance (4)
4.Religious ambiguity(3,4)
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Pt. III. Essay (a) teleological
(design) argument or (b)
problem of evil.
Part IV. Multiple choice
1. Definitions- libertarianism,
hard determinism,
compatibilism. 2. Problem of
evil as objection to argument
for God’s existence. 3. Why
Plato opposes prayer/sacrifice
piety. 4. Definition of “rational
agent.” 5. Why Mill thinks God
is finite. 6. Heraclitus’ main
point. 7. Famous Socrates
quote.