8/10/2019 Prior, Rejoinder to Professor Lachs on Omniscience

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DISCUSSION

REJOINDER

TO

PROFESSOR

LACHS ON

OMNISCIENCE

A. N. PRIOR

1.

Knowing

what

does

not

seem

to me to

be

anything

different in

itself

from

knowing

that ;

it is

simply

how

knowing

that

may

appear

to

someone

who does

not

share the

piece

of

knowledge

in

question.

For

example,

my

own

knowing

what

2

and

2

are,

simply

is

my knowing

hat

2

and

2

are

4;

but a

person

who does

not himself know that

2

and

2

are

4,

and

who

therefore cannot

know

that

I

know that

2

and

2

are

4,

might

nevertheless know that I know what 2 and 2 are. (He would know that I

know what

they

are

without

knowing

what

I

know

them to

be.) Sym-

bolically

we

can

easily

do

it

all

in

terms

of

knowing

that

and

quantifiers,

as

follows:

(a)

I

know what

2

and

2

are

=

For

some

x,

I

know

that

2

and

2 are

x.

(b)

He

knows

that

I

know

what

2

and

2

are

=

He knows that for

some

x,

I

know

that

2 and 2

are

x .

(c)

He

knows what

I

know 2 and

2 to be

=

For

some

x,

he

knows

that

I

know that

2 and 2

are x .

2. I don t see

why

God shouldn t knowwhat

doubting

is without himself

experiencing

it.

For to doubt whether

p

is

simply

not

to know

that

p

and

not to

know

that

not

p;

at

least,

for all that Lachs

has

shown

to the con-

trary,

that is

what

doubting

whether

p

is;

and

anyone

can

understand

this

who

has

had

experience

of

knowledge.

3.

I

agree,

however,

that Lachs is on

to

something

here.

Knowing

whether

p,

and even

knowing

what it is to know

whether

p,

do

seem in

some cases to

presuppose

having

experiences,

e.g.

toothaches

and

sinking

feelings

and

dismay,

which

it

is difficult to

imagine

a

divine

being

as

having. I may, for example, mentally advert to a pain which I am experi-

encing,

and

ask

myself,

in

my

private

language,

whether God

knows

that

a

toothache feels to

me

like

this,

and

I

do not see how

God

can

know either

that or

anything

else

directly

involving

a sensation

of this

quality

without

actually having

one.

I

don t

know,

however,

of

any

proof

that

having

such

experiences

would be

incompatible

with

omniscience;

hat

emerges

here is

rather

a

question

as

to whether

omniscience

is

itself

compatible

with other attributes

traditionally

ascribed to

divine

beings.

4.

As

to

time,

Lachs is

right

in

suspecting

that

I

do not

admit

a

single

class

of true

propositions

to which the

same

propositions belong

at all

times. I don t think I can

even

swallow

his

super-class

S.

My

metalogic

at

this

point

has the

same essential

features as

my

logic.

Certainly

we

can

talk

sensibly

not

only

about

the set

of

propositions

which have

been

true and

the set of

those which are

true

now,

but also about the

set of those

which

will

be

true,

and

more

particularly

about,

say,

the

set of those

which will be true

tomorrow.

And

an

omniscient

being

must

know what

propositions

are in

the latter

sets

as

well

as

what

ones

are in

the

former.

This

follows

immedi-

ately

from

proposition

(9)

of

my

article,

together

with the reasonable

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8/10/2019 Prior, Rejoinder to Professor Lachs on Omniscience

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PHILOSOPHY

assumption

that It will be

the case

that

p

is true

when

and

only

when

the

plain

p

will

be true. But there s

a

point

here that

needs to be

carefully

stated if we are to avoid self-contradiction. The set of propositions that

are true

today

includes a few that

were

not

yesterday

in

the set

then

correctly

labelled

propositions

that will

be true

tomorrow

(because

yesterday

what

would

happen

was

still,

at

some

points,

undecided).

And

it will be true

omorrow

hat the set

of

propositions

then

rue includes

some

which were not the

day

before

(i.e.

the

day

we

now

call

today ) among

those

correctly

labelled

propositions

that will be true tomorrow .

But

we

cannot

say

now which

propositions

these

ones

will

be; indeed,

it isn t

yet

the

case with

respect

to

any specific

proposition

that

it

will

be

in

this

group (if

it

were,

we

wouldbe

landed

with

a

contradiction);

what

is the

case

now

is

just

the

generalpoint

enunciated

in the

last

sentence.

Here,

as

with

knowing

what ,

we must watch where

our

quantifiers go.

What we

have

is that it will be thecasetomorrowhat

certain

specific

propositions

are

of this

odd sort

(true

without

having

been

going-to-be-true

the

day

before);

what

we don t

have

is

that there now are

certain

specific

proposi-

tions which will be tomorrowf

that

sort.

The

theory

of sets of

propositions,

in

short,

must be

handled

with the

same

circumspection

at this

point

as

the

theory

of

everything

else.

ManchesterUniversity.

ON POINTING

E. C. EVANS

ON

page

218

of his article The

Theory

f

Translation

n

the issue for

July

1962,

Mr

Haas

argues against

the

possibility

of

establishing

a

language

by means of rules of reference alone. Pointing is found to be ambiguous

when

not

accompanied

by

other

language:

this

shows that

if

it were the

only

language

it

couldn t

be used to

establish

another.

By

itself it

would

be

hopelessly

ambiguous. (At

a

race,

how

do

we

point

at the

track,

at a

horse,

its

rider,

his

number.

. .

?) (My

dots.)

Now in

fact,

I

maintain,

pointing-gestures

are

usually

quite

unam-

biguous

whether

or

not

they

are

accompanied by

other

language.

Mr

Haas

may

not

believe

this,

but

I

suspect

he acts as

if

he

did,

like

every-

body

else. For

example,

I

drop

my

pocket-book

and

someone

taps

me on

the

shoulder and

points

to

where

it

lies.

Where

is

the

ambiguity?

An indicative movement is not really very like a word-for one thing

it is

already being

used-but

given

that one

thinks

it is

(see

p.

218,

second

paragraph)

the idea that

by

itself

it

must

be

ambiguous

follows

quite

naturally.

One asks oneself what it

means,

and

the answer

comes

to

mind

that it

means,

near

enough,

that

the other

person

should look. It

is then

rather

easy

to

suppose

that the function of

an

indicative

movement

is

always

or

nearly always

to

say

look.So

attendance

at a

spectacle,

such

as

a

horse-race,

presents

itself

as

a

typical

context of

use,

and

searchlight-

366

PHILOSOPHY

assumption

that It will be

the case

that

p

is true

when

and

only

when

the

plain

p

will

be true. But there s

a

point

here that

needs to be

carefully

stated if we are to avoid self-contradiction. The set of propositions that

are true

today

includes a few that

were

not

yesterday

in

the set

then

correctly

labelled

propositions

that will

be true

tomorrow

(because

yesterday

what

would

happen

was

still,

at

some

points,

undecided).

And

it will be true

omorrow

hat the set

of

propositions

then

rue includes

some

which were not the

day

before

(i.e.

the

day

we

now

call

today ) among

those

correctly

labelled

propositions

that will be true tomorrow .

But

we

cannot

say

now which

propositions

these

ones

will

be; indeed,

it isn t

yet

the

case with

respect

to

any specific

proposition

that

it

will

be

in

this

group (if

it

were,

we

wouldbe

landed

with

a

contradiction);

what

is the

case

now

is

just

the

generalpoint

enunciated

in the

last

sentence.

Here,

as

with

knowing

what ,

we must watch where

our

quantifiers go.

What we

have

is that it will be thecasetomorrowhat

certain

specific

propositions

are

of this

odd sort

(true

without

having

been

going-to-be-true

the

day

before);

what

we don t

have

is

that there now are

certain

specific

proposi-

tions which will be tomorrowf

that

sort.

The

theory

of sets of

propositions,

in

short,

must be

handled

with the

same

circumspection

at this

point

as

the

theory

of

everything

else.

ManchesterUniversity.

ON POINTING

E. C. EVANS

ON

page

218

of his article The

Theory

f

Translation

n

the issue for

July

1962,

Mr

Haas

argues against

the

possibility

of

establishing

a

language

by means of rules of reference alone. Pointing is found to be ambiguous

when

not

accompanied

by

other

language:

this

shows that

if

it were the

only

language

it

couldn t

be used to

establish

another.

By

itself it

would

be

hopelessly

ambiguous. (At

a

race,

how

do

we

point

at the

track,

at a

horse,

its

rider,

his

number.

. .

?) (My

dots.)

Now in

fact,

I

maintain,

pointing-gestures

are

usually

quite

unam-

biguous

whether

or

not

they

are

accompanied by

other

language.

Mr

Haas

may

not

believe

this,

but

I

suspect

he acts as

if

he

did,

like

every-

body

else. For

example,

I

drop

my

pocket-book

and

someone

taps

me on

the

shoulder and

points

to

where

it

lies.

Where

is

the

ambiguity?

An indicative movement is not really very like a word-for one thing

it is

already being

used-but

given

that one

thinks

it is

(see

p.

218,

second

paragraph)

the idea that

by

itself

it

must

be

ambiguous

follows

quite

naturally.

One asks oneself what it

means,

and

the answer

comes

to

mind

that it

means,

near

enough,

that

the other

person

should look. It

is then

rather

easy

to

suppose

that the function of

an

indicative

movement

is

always

or

nearly always

to

say

look.So

attendance

at a

spectacle,

such

as

a

horse-race,

presents

itself

as

a

typical

context of

use,

and

searchlight-

366