philosophy questions and summary 1 page

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

th

eory

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,

an

d

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,

exte

nsion,

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

Lock

e'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

exam

ple,

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

re

lationship

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

infini

tum.

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 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 material objects, that the essence of everything is in

being perceived. Although Bekeley denied material substance, he accepts that there are mental

substances.