Descartes’ Ontological Argument

Born: 31 March 1596 in La Haye (now Descartes), Touraine, France Died: 11 Feb 1650 in Stockholm, Sweden

Terminology of the OA

Descartes was primarily concerned with God’s essence , or nature .

God’s essence is described by showing his attributes , or predicates , or perfections

Put Descartes into context

Anselm’s 11 th c. argument: 1. God is that than which nothing greater (more perfect) can be conceived 2. Ttwngcbc must exist, since an imaginary being twngcbc would be less perfect than a real being twngcbc.

Why was Anselm turned to stone?

- because he could see into the future, and had seen the work of 14,999 A level candidates who all wrote that his ontological argument was a

“reductio ad absurdum”.

Then he saw what the 15,000 th had written: candidate

Anselm’s argument was a “rectum ad absurdum”

Aquinas’ rejection (13

th

c.)

The OA only works if we know God’s essence.

We do not know God’s essence.

So God’s existence can be known only by our sense experience of the universe (hence Aquinas’ 5 ‘Ways’).

Is that true

Ttwngcbc seems a reasonable place to start. Also, we could also say that we can have an ‘adequate’ idea of an all-powerful / perfect being without our having to be able to work out every single attribute that such a being would have.

Descartes

Assumptions : 1. Our senses can always deceive us 2. God exists to guarantee the consistency and reliability of our sense perceptions.

The lesson learned?

1. Doubt can be removed by returning to the basics. With the mind, the fact that I think gives me one fact about which I can’t be deceived – I exist: CES 2. So with things, to avoid deception, I must ask what is their essence – that part of a thing about which there is no argument?

The essence of a triangle

3 sides, 3 angles 180 degrees

The essence of mountains

The essence of God

Existence Perfection Singularity In fact: every perfection

A 2nd stage to the argument

As in Anselm II We must distinguish between ‘ordinary’ existence and ‘necessary existence’

Things have contingent existence

The same is true of ‘construct things’ like Pegasus Bellerophon riding Pegasus

Pegasus has ordinary existence, so like all contingent things, might not exist God must possess necessary existence, otherwise he would not be the supremely perfect being .

The argument reformulated tin response to Caterus

1. Whatever is of something’s essence must be affirmed of it: e.g. “all mammals are warm-blooded” 2. By definition, God’s essence is his existence 3. Therefore existence must be affirmed of God.

Objection 1: Hume

Hang on, laddie, No existential statement can be analytic – they’re all synthetic

J.L. Mackie

 “It is not simply obvious and indisputable that there cannot be analytic existential truths”  Maffs?  But maffs is logical, ‘God exists’ is a factual statement.

Objection 2: Kant

Real predicates can’t be rejected (as with real triangles), but imaginary ones can, as with imaginary triangles and imaginary gods.

Yet More Kant

 Moreover, sunshine, existence is not a predicate: ‘exist’ adds nothing to the subject in phrases like ‘cows exist’  Try the effect of

‘it exists’

Kant once again

 The same is true with describing God’s other ‘predicates’ –

omnipotent, omniscient, omnibenevolent

, etc., because our idea of God already contains them  So we can reject

all

of God’s supposed predicates

Kant’s swansong

“The attempt to establish the existence of a supreme being by means of the … OA … is therefore so much labor and effort lost; we can no more extend our stock of [theoretical] insight by mere ideas than a merchant can better his position by adding a few noughts to his cash account.”

The crucial word in the OA

if

All the OA does is to establish possibilities

If

God exists, then God exists necessarily, omnipotently, omnisciently, etc.

The problem is that there is no guarantee that God does exist.

‘Wahoo, buddy!’ – Norman Malcolm rides to the rescue

‘Ordinary’ existence is not a predicate, but ‘necessary’ existence seems as if it is. It tells you that God has to exist.

1. If God came into existence now, he would be contingent, and so would not be God.

2. Therefore if God does not exist now, his existence is impossible. [

why?]

3. Therefore God’s existence is either impossible or necessary.

4. God’s existence can be impossible only if the concept of such a being is self-contradictory or logically absurd.

5. It isn’t, therefore God exists necessarily.

6. So in the same way, God is necessarily omnipotent and omniscient.

This is an

analytic existential truth

, in the same way that the infinity of the sequence of prime numbers (1,3,5,7,11,13 etc.) is an analytic existential truth.

You either grasp this, or you don’t. Once you do, no doubt remains as to whether or not God exists.

Baloney, Mahoney

Any competent mathematician could demonstrate the infinity of the sequence of prime numbers as a mathematical fact. It does not require intuitive understanding, only intelligence.

Moreover

Reduce: ‘a self-contradictory notion’ to (x) And: ‘logically absurd’ to (y) And: ‘God exists’ to (z)

Reduce Malcolm’s argument to: not (x) + not (y) = (z) (not s.c. and not l.a. = God exists) But this equation can also be solved by: not (x) + not (y) = not (z) Not s.c. and not l.a. = God

doesn’t

exist

Malcolm – Darn it, let’s say the OA has anti-real force.

This is the argument that the OA is an argument for those who believe in God.

But : 1.

Either the OA works or it doesn’t 2. If it doesn’t, what’s the point of believers using it?

Alvin Plantinga

Plantinga as the cavalry: A modal version of the OA

Modal Logic

uses a system of possible but non-actual worlds to give a framework by which you can judge what is possible and what is necessary in the real world it

isn’t

the ‘many worlds’ interpretation of quantum theory

‘maximal excellence’

a being having maximal excellence is one possessing all the Cartesian perfections: omnipotence, omniscience, aseity, perfection, etc.

‘maximal greatness’

- a being possesses maximal greatness if it possesses maximal excellence in all possible worlds.

World-Indexed properties

1. Consider all possible worlds, and label them W1, W2, W3, W4 and so on 2. Consider Gordon Brown in worlds 1,2,3,5,7,9,23,45,67,467,2385, etc.

3.

To be the same

GB in W467 as in W1, GB in W467 has to have some recognisable features

No WIPS here

To say that properties are world indexed means: 1. For something to exist in more than one possible world, it cannot vary significantly from world to world.

2. Whatever is necessary or impossible cannot vary at all from world to world.

(why not)

So the same is true for God

God could not vary at all from world to world. A being who is not omnipotent in W8 cannot be the same as a being who is omnipotent in W1,W2,W3,W4,W5,W6 and W7, because a non-omnipotent being would not be recognisable

as

God.

Now follow the logic:

( 1) We aim to demonstrate the existence of God (a being with maximal greatness) (2) Such a being must possess maximal excellence in all possible worlds (3) Because of WIPS, if we can show that there is a being of maximal excellence in just

one

possible world, then we have proved that such a being exists in

all

possible worlds

4. There is a being of maximal excellence in one possible world, because the idea of such a being is either necessary or impossible.

5. It can be impossible only if the idea of such a being is s.c. or l.a.

6. It isn’t, therefore such a being exists necessarily in one possible world.

7. Whatever is necessary or impossible cannot vary at all from world to world.

8. So such a being exists in all possible worlds.

9. Therefore God has maximal greatness and necessary existence: God exists.

Why doesn’t this work?

1. because: not … 2. We could have a term

‘no maximality’ ,

which is the property of no world possessing a maximally great being, in which case the same flow of argument could be used to demonstrate the non existence of God in every possible world, including this one.

Synthesis – the OA fails on 2 fronts: 1. ‘existence’ isn’t a predicate. As Russell & Frege say: it’s an

existential quantifier -

it means ‘are instances of’.

‘Tame tigers exist’ means: ‘there are instances of tame tigers’, which I can only know from experience.

I cannot know that ‘there is an instance’ of God.

Timmy

(2) Statements asserting God’s existence are tautologies ‘God is an omnipotent being’ Reduces to: ‘God (an omnipotent being) is an omnipotent being’.

This is a tautology - analytic / true by definition / but

factually

true only

if

there is a God.

Unpack ‘God’ – it is shorthand for a number of predicates Each concept/predicate you add just adds to the tautology E.g. ‘God (an omnipotent, omniscient, immutable being who has necessary existence) exists omnipotently, omnisciently and immutably and necessarily’

ALL tautologies are analytic – they are necessarily/logically true – they have ‘de dicto’ necessity.

But they may be factually false, because no analytic statement can give you knowledge of the facts – you have to know the facts first

There is one exception that causes confusion ‘God has necessary existence’

is

a tautology (a being who possesses n.e. has n.e.

But we could say ‘God necessarily exists’ This

isn’t

a tautology, because it means: ‘a being who possesses n.e.

must

exist’

‘a being who possesses n.e. must exist’ But this may be false. ‘Having to exist’

is

a predicate, and

if

God exists, he has to exist, because then he possesses the predicate of having to exist. But there is still no guarantee that such a being exists. If it does not exist, then obviously it does not possess n.e.

Conclusion

‘God exists’ is analytic in form.

It may be either factually true or factually false.

The OA fails.

Salvage

The 20 th c. Swiss theologian Karl Barth thinks that Anselm intended his argument as a prayer

This is because (1) Anselm starts and ends Proslogium with a prayer, and (2) He thinks that Anselm received his definition of God as ttwnccbc as a self-revelation from God.

But

1.

one Anselm says that he has been looking for a ‘proof’, and now has found 2.

He means it as an analytic proof.

3. If his argument was just a prayer, why did Gaunilo object to it, and why did Anselm take Gaunilo’s objection as a logical objection to the argument?

Norman Malcolm again

The OA won’t convince atheists, and is an anti-real argument – it ‘coheres’ with truth in the believing community Really? What use is an anti-real argument to believers?

All the believers I know take ‘God exists’ to be cognitive/factual

The value of the OA

1.

to ‘blood’ generations of students and drive them insane.

2. It is also a part of the history of philosophy.