The Modern philosophers starting with Rene Descartes were mostly concerned with how one can know and reach truth. The theory of knowledge is known as "epistemology". There were two branches in epistemology, rationalism and empiricism. Rationalism is the theory according to which reason is the only source of knowledge, everything else is opinion or belief. Empiricism is the theory according to which the source of human knowledge is experience.  Rene Descartes was a rationalist, who doubted everything (method of doubt) in order to reach an absolute indubitable foundation of from which to build up knowledge. The foundation is called "Cogito Ergo Sum", "I think therefore I am" that is the existence of an absolute rational being from which he derived the existence of mind and matter.  According to Locke human beings are not born with any innate ideas, all ideas are learned either via sense experience or via reflection. Sense experience gives us ideas about the external world, while reflection gives us ideas about our own mind. According to Locke, there are two types of ideas that we acquire from sense experience, simple and complex. Simple ideas are those that are acquired via one sense, say touch, and cannot be broken down further. Complex ideas are made up of several simple ideas, such as, the idea of a red cloth. Further, each object has primary and secondary qualities. Primary qualities are those which are inseparable from the object, such as, extension, solidity, motion, while secondary qualities such as color are separable from matter. Locke assumes that there is a material substance as an underlying support of primary qualities, which he describes as "unknown and unknowable". Bekeley refutes Locke's idea of a material substance. According to Berkeley if we assume that there is a material substance underlying the primary qualities, then we should be able to explain the relationship between the quality and the underlying material substance, for example, extension and the substance. Now, if the relationship is one of spreadness, that is extension is spread on the material substance, then we need to explain is "spreadness" is a substance or a quality, If it is a substance then we need to explain the relationship between spreadness, as a substance and the quality of extension, if it is a quality, then we need to explain the relationship between the quality "spreadness" and the underlying substance, for which we need another spreadness and so on ad infinitum. Further, the materiality of the substance as "out there" does not hold, as the size of the substance depend upon the location of the perceiver, a car appears small from a plane and large when I stand by it. Moreover, we experience things in a series, a, b, c, d... and store them in memory, such that when we experience a, we expect b to come and so forth. For a person born blind who has no such memory, if given vision will experience things in blotches. These show that there is are no mater ...

1. The Modern philosophers starting with Rene Descartes were
mostly concerned with how one can know and reach truth. The
theory of knowledge is known as "epistemology". There were
two branches in epistemology, rationalism and empiricism.
Rationalism is the theory according to which reason is the only
source of knowledge, everything else is opinion or belief.
Empiricism is the theory according to which the source of
human knowledge is experience.
Rene Descartes was a rationalist, who doubted everything
(method of doubt) in order to reach an absolute indubitable
foundation of from which to build up knowledge. The
foundation is called "Cogito Ergo Sum", "I think therefore I
am" that is the existence of an absolute rational being from
which he derived the existence of mind and matter.
According to Locke human beings are not born with any innate
ideas, all ideas are learned either via sense experience or via
reflection. Sense experience gives us ideas about the external
world, while reflection gives us ideas about our own mind.
According to Locke, there are two types of ideas that we
acquire from sense experience, simple and complex. Simple
ideas are those that are acquired via one sense, say touch, and
cannot be broken down further. Complex ideas are made up of
several simple ideas, such as, the idea of a red cloth. Further,
each object has primary and secondary qualities. Primary
qualities are those which are inseparable from the object, such
as, extension, solidity, motion, while secondary qualities such
as color are separable from matter. Locke assumes that there is
a material substance as an underlying support of primary
qualities, which he describes as "unknown and unknowable".
Bekeley refutes Locke's idea of a material substance. According
to Berkeley if we assume that there is a material substance
underlying the primary qualities, then we should be able to

2. explain the relationship between the quality and the underlying
material substance, for example, extension and the substance.
Now, if the relationship is one of spreadness, that is extension
is spread on the material substance, then we need to explain is
"spreadness" is a substance or a quality, If it is a substance then
we need to explain the relationship between spreadness, as a
substance and the quality of extension, if it is a quality, then we
need to explain the relationship between the quality
"spreadness" and the underlying substance, for which we need
another spreadness and so on ad infinitum. Further, the
materiality of the substance as "out there" does not hold, as the
size of the substance depend upon the location of the perceiver,
a car appears small from a plane and large when I stand by it.
Moreover, we experience things in a series, a, b, c, d... and
store them in memory, such that when we experience a, we
expect b to come and so forth. For a person born blind who has
no such memory, if given vision will experience things in
blotches. These show that there is are no material objects, that
the essence of everything is in being perceived. Although
Bekeley denied material substance, he accepts that there are
mental substances.
The
Modern
philosophers
starting
with
Rene
Descartes

3. were
mostly
concerned
with
how
one
can
know
and
reach
truth.
The
theory
of
knowledge
is
known
as

4. "epistemology".
There
were
two
branches
in
epistemology,
rationalism
and
empiricism.
Rationalism
is
the
th
eory
according
to
which

5. reason
is
the
only
source
of
knowledge,
everything
else
is
opinion
or
belief.
Empiricism
is
the
theory
according

6. to
which
the
source
of
human
knowledge
is
experience.
Rene
Descartes
was
a
rationalist,
who
doubted
everything

7. (method
of
doubt)
in
order
to
reach
an
absolute
indubitable
foundation
of
from
which
to
build
up
knowledge.

8. The
foundation
is
called
"Cogito
Ergo
Sum",
"I
think
therefore
I
am"
that
is
the
existence
of
an

9. absolute
rational
being
from
which
he
derived
the
existence
of
mind
and
matter.
According
to
Locke
human

10. beings
are
not
born
with
any
innate
ideas,
all
ideas
are
learned
either
via
sense
experience
or
via

11. reflection.
Sense
experience
gives
us
ideas
about
the
external
world,
while
reflection
gives
us
ideas
about
our
own

12. mind.
According
to
Locke,
there
are
two
types
of
ideas
that
we
acquire
from
sense
experience,
simple
and

13. complex.
Simple
ideas
are
those
that
are
acquired
via
one
sense,
say
touch,
an
d
cannot
be
broken
down

14. further.
Complex
ideas
are
made
up
of
several
simple
ideas,
such
as,
the
idea
of
a
red
cloth.

15. Further,
each
object
has
primary
and
secondary
qualities.
Primary
qualities
are
those
which
are
inseparable
from
the
object,

16. such
as,
exte
nsion,
solidity,
motion,
while
secondary
qualities
such
as
color
are
separable
from
matter.
Locke
assumes

17. that
there
is
a
material
substance
as
an
underlying
support
of
primary
qualities,
which
he
describes
as
"unknown

18. and
unknowable".
Bekeley
refutes
Lock
e's
idea
of
a
material
substance.
According
to
Berkeley
if
we
assume
that
there

19. is
a
material
substance
underlying
the
primary
qualities,
then
we
should
be
able
to
explain
the
relationship
between

20. the
quality
and
the
underlying
material
substance,
for
exam
ple,
extension
and
the
substance.
Now,
if
the
relationship

21. is
one
of
spreadness,
that
is
extension
is
spread
on
the
material
substance,
then
we
need
to
explain

22. is
"spreadness"
is
a
substance
or
a
quality,
If
it
is
a
substance
then
we
need
to
explain

23. the
re
lationship
between
spreadness,
as
a
substance
and
the
quality
of
extension,
if
it
is
a
quality,
then

24. we
need
to
explain
the
relationship
between
the
quality
"spreadness"
and
the
underlying
substance,
for
which
we
need

25. another
spreadness
and
so
on
ad
infini
tum.
Further,
the
materiality
of
the
substance
as
"out
there"
does

26. not
hold,
as
the
size
of
the
substance
depend
upon
the
location
of
the
perceiver,
a
car
appears

27. small
from
a
plane
and
large
when
I
stand
by
it.
Moreover,
we
experience
things
in
a
series,

28. a,
b,
c,
d...
and
store
them
in
memory,
such
that
when
we
experience
a,
we
expect
b

29. to
come
and
so
forth.
For
a
person
born
blind
who
has
no
such
memory,
if
given
vision

30. will
experience
things
in
blotches.
These
show
that
there
is
are
no
material
objects,
that
the
essence
of

31. everything
is
in
being
perceived.
Although
Bekeley
denied
material
substance,
he
accepts
that
there
are
mental
substances.
The Modern philosophers starting with Rene Descartes were

32. mostly concerned with how one can
know and reach truth. The theory of knowledge is known as
"epistemology". There were two
branches in epistemology, rationalism and empiricism.
Rationalism is the theory according to
which reason is the only source of knowledge, everything else is
opinion or belief. Empiricism is
the theory according to which the source of human knowledge is
experience.
Rene Descartes was a rationalist, who doubted everything
(method of doubt) in order to reach an
absolute indubitable foundation of from which to build up
knowledge. The foundation is called
"Cogito Ergo Sum", "I think therefore I am" that is the
existence of an absolute rational being
from which he derived the existence of mind and matter.
According to Locke human beings are not born with any innate
ideas, all ideas are learned either
via sense experience or via reflection. Sense experience gives
us ideas about the external world,
while reflection gives us ideas about our own mind. According
to Locke, there are two types of
ideas that we acquire from sense experience, simple and
complex. Simple ideas are those that are
acquired via one sense, say touch, and cannot be broken down
further. Complex ideas are made
up of several simple ideas, such as, the idea of a red cloth.
Further, each object has primary and
secondary qualities. Primary qualities are those which are
inseparable from the object, such as,
extension, solidity, motion, while secondary qualities such as
color are separable from matter.
Locke assumes that there is a material substance as an
underlying support of primary qualities,

33. which he describes as "unknown and unknowable".
Bekeley refutes Locke's idea of a material substance. According
to Berkeley if we assume that
there is a material substance underlying the primary qualities,
then we should be able to explain
the relationship between the quality and the underlying material
substance, for example,
extension and the substance. Now, if the relationship is one of
spreadness, that is extension is
spread on the material substance, then we need to explain is
"spreadness" is a substance or a
quality, If it is a substance then we need to explain the
relationship between spreadness, as a
substance and the quality of extension, if it is a quality, then we
need to explain the relationship
between the quality "spreadness" and the underlying substance,
for which we need another
spreadness and so on ad infinitum. Further, the materiality of
the substance as "out there" does
not hold, as the size of the substance depend upon the location
of the perceiver, a car appears
small from a plane and large when I stand by it. Moreover, we
experience things in a series, a, b,
c, d... and store them in memory, such that when we experience
a, we expect b to come and so
forth. For a person born blind who has no such memory, if given
vision will experience things in
blotches. These show that there is are no material objects, that
the essence of everything is in
being perceived. Although Bekeley denied material substance,
he accepts that there are mental
substances.
1. Weekly summaries: A brief summary of what you learned
during the week will be due every Sunday by midnight.

34. Summaries should briefly describe everything the student
learned during the week. Upload the summary in the
“assignment” area, not the “comment” area. A sample summary
will be provided on which the students can model their
summaries. Total point 15.
Example Summary.
This week we learned about the two trends in epistemology (or
the theory of knowledge that inquires into how we know),
rationalism and empiricism. According to rationalism all our
knowledge come from reason, while according to empiricism all
our knowledge come from senses. The first theorist we learned
about is a rationalist, Rene Descartes. Descartes wanted to
model metaphysical knowledge on natural sciences, for the
latter is objective and universal. He thought that the reason for
the objectivity in the sciences is due to its rigorous method,
which is absent in metaphysical knowledge. So he proposed the
methodological doubt by which he doubted everything till he
reached an absolute truth that is indubitable from which he
would build his entire metaphysical theories. Descartes doubted
his senses, all that he learned so far, and even mathematical
knowledge and reached the one thing that he could not doubt
that he exists as a thinking being "Cogtio Ergo Sum". From his
Descartes derived the existence of matter having extension as
its essential attribute and mind. Next we studied the
philosophies of two empiricist thinkers, John Locke and George
Berkeley. According to Locke the mind at birth is a tabula rasa
or clean slate and all our ideas come to us via experience,
sensations, that give us ideas about the external world and
reflection that give us ideas about our own mind. A child is not
born with the idea that 2+2=4, but learns it, agrees with it, and
stores it in his memory and it becomes part of his knowledge.
According to Locke there are simple ideas (those that cannot be
broken down further), and complex ideas (those which the mind
forms from simple ideas). The mind is passive in receiving

35. ideas but active in combining them and forming complex ideas.
Further, matter has two types of qualities, primary and
secondary. A primary quality is a permanent feature of matter
like extension, solidity, motion, while a secondary quality is
sometimes in matter and sometimes not there, depending on
conditions. For example, color, taste, smell, etc. As an
empiricist Locke could not accept the idea of "substance",
nonetheless, he theorized that he has a vague idea of a
substance as the unknown and unknowable support of primary
qualities. Berkeley rejected Locke's idea of the substance as the
support of primary qualities. For Berkeley, the question is what
is the relationship between the primary quality extension and
the underlying mysterious substance. If the relationship is one
of spreadness (that is extension is spread on the substance),
then Locke has to explain what is "spreadness", is it a quality or
is it substance itself. If it is a quality then one needs to posit
another spreadness to explain the relationship between
substance and the underlying substance. If it is substance itself,
then what is the relationship between extension and this
substance called spreadness, either way the theory of substance
does not hold. For Berkeley the essence of everything is
perception, for example, a tree appears big if someone is
standing beside it, small if one looks at it from the top of a
mountain, which shows that even the sizes of things are not
objective but depends on human perception. Further, when we
experience something we experience them in a series, x, then y,
and then Z and so on and store them in our memories, such that
next time when we experience x, we expect y to come and so
forth. A person born blind has no such memory as he has not
experienced the series, so when he experience things, he will
experience them in blotches and not as a series. This shows that
the external world is not material but constructed by our
perception. Although Berkeley did not agree with material
substances of Locke, he agreed with mental substances as the
support of mental qualities like thinking, doubting, believing,
etc.

36. 1.. What was the purpose of Descartes's "methodological
doubt"? What are the things he doubted?
2. The "cogito" is a disembodied universal rationality that
Descartes reached at the end of his methodological doubt. In
addition he also reasoned that there must be another thing that
is real. What is it, how did he reach that conclusion?
[Hint: Descartes used his methological doubt to reach an
absolute "truth", meaning a truth that is objective and that will
force him to accept it. He reached "Cogito" from which he built
his entire philosoph. Then, via his "wax experiment" he reached
the truth (only via reason, not via experimentation), that if he
holds a fresh piece of wax near the fire, all its previous
qualities will transform, but something extended, "waxy"
"waxness" will remain, as extended in space. Matter is
something extended in space; so for him there are two ultimate
substances, mind and matter].
3. According to Locke human beings are not born with innate
ideas, they acquire ideas via sensation and reflection. State
clearly, with examples, in your own words Locke's argument for
stating the above.
[Hint: S, a child, is not born with the idea that 2+2=4, but
learns it, agrees with it, and stores it in his memory and it
becomes part of his knowledge. Do NOT use this example in
your answer].
4. Do you have any idea in your mind that you did not learn
from someone or somewhere and that you never had an
experience before. State "yes" or "no". If "yes" say how did
you get that idea in your mind? ( For example, sometimes you
go to some place and have a feeling you know that place, but
you have never been there, nor heard, read, or been told about
that place, nor does it resemble anything you are familiar with
and you start wondering if it was in your mind and where it
came from).

37. 5. Locke was an empiricist and could only rely on sense
perception and reflection to assert that certain things exist.
Nonetheless, he asserted the existence of "material substance"
as the unknown "substrate" that holds the primary qualities. Do
you think in doing that Locke showed some inconsistencies in
his philosophy.
According to Berkeley, the sizes of things change with location,
which shows that things are not "out there" or lack objectivity.
7. Describe one experience you had where the size and shape of
a thing changed with the change in your location.