Descartes' second proof of God's existence in the Meditations

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xris
 
Reply Fri 15 May, 2009 05:10 am
@kennethamy,
kennethamy wrote:
God is perfect by definition, just as a triangle has three angles, by definition.
Whose definition yours? It comes from hypothesising not observing.I dont see god if he exists as perfect, you have to observe his perfect creation to make that assumption by evidence.Its like saying water is wet therefore its salty.
 
Bones-O
 
Reply Fri 15 May, 2009 05:38 am
@kennethamy,
kennethamy wrote:

But Descartes does not say that triangularity is a condition of the triangle's existence.

And that is precisely why the analogy falls down: they are not analogous. A triangle having three angles is not analogous to a god that exists, since one is a truism and one is not.

kennethamy wrote:
It is not a necessary condition of a winged horse that it exist.

If my idea of a winged horse is as Descartes' is of God, that it must exist, then it must exist. This is precisely my point: I can include the existence of a thing in idea of a thing and thus prove the thing exists.

kennethamy wrote:
What Descartes argues is that if God is a perfect Being, and if perfection implies existence, then a perfect Being must exist.

This is his first proof, no? The second proof is that Descartes cannot separate the idea of God from his existence, and since he has the idea, God must exist. The first proof is that since God is perfect, i.e. has the most objective reality, he must be the most real thing, thus he exists. This proof is about what God must be irrespective of Descartes thinking about him; the second is what God must be given the idea Descartes has of him. Descartes does not use God's perfection as part of his second proof (though does talk about it in meditation 5 as a whole).

As I said, I'm happy to talk about the first proof later, but I'd like to discuss the second for now. Descartes' argument that existence of God is part of his essence is:

Descartes wrote:

For what, in and of itself, is more manifest than that a supreme being exists, that is, that God, to whose essense alone existence belongs, exists?


---------- Post added at 06:47 AM ---------- Previous post was at 06:38 AM ----------

Theaetetus wrote:
David Hume brings up a nice counter argument that can be applied to Descartes. We are not justified in attributing more to God than we can gather from the environment. Because the world is imperfect, we cannot assume that God would be perfect. I don't know if that helps at all, but it is a good argument against the idea that God is a perfect being.

Thanks. I think Descartes would dismiss this out of hand on the grounds that what is gathered from the environment is to be rejected as tenuous. Descartes' idea of God's perfection is claimed to be innately in him, or given him by God, and so is more trustworthy.

I think much of the theological side of meditations is sleight of hand or simple proclamation. Descartes gets a lot of mileage out of simply stating: "I have this idea, I grasp that notion" etc. This is why I'm attracted to my second disproof: Not-God --> Not-Idea... It basically sums up everything wrong with Meditations: Just because you can write (or say) "I have an idea of a perfect and infinite being whose essence includes its existence" it does not follow one can actually grasp such a thing. In short, I just call BS on him actually perceiving what he claims to perceive and find that God then doesn't have to exist. Smile

---------- Post added at 06:50 AM ---------- Previous post was at 06:38 AM ----------

xris wrote:
Whose definition yours?

By Descartes'... the topic of discussion. No other definition than Descartes' is relevant to this thread.
 
xris
 
Reply Fri 15 May, 2009 06:09 am
@Bones-O,
So do we question the definition? or the reasoning?
 
Theaetetus
 
Reply Fri 15 May, 2009 07:57 am
@Bones-O,
Sorry if I missed it, but here are the two versions of Descartes' ontological proof for God's existence that he uses in Meditation V. This should help you see what you should be questioning, xris. Typically you question the premises so on both versions arguing against both 1 and 2 is fair game.

[INDENT]Version A:
  1. Whatever I clearly and distinctly perceive to be contained in the idea of something is true of that thing.
  2. I clearly and distinctly perceive that necessary existence is contained in the idea of God.
  3. Therefore, God exists.

[/INDENT][INDENT]
Version B
:
  1. I have an idea of supremely perfect being, i.e. a being having all perfections.
  2. Necessary existence is a perfection.
  3. Therefore, a supremely perfect being exists.

[/INDENT]
 
Bones-O
 
Reply Fri 15 May, 2009 08:01 am
@xris,
xris wrote:
So do we question the definition? or the reasoning?


Hi xris. I'm questioning the reasoning here, but there's scope to discuss the definition. Definitions are important for the first proof, and I think the first proof is important for the second, even if it shouldn't be. :shifty:

Ken :- I see the issue here, actually two of them with regards to the second proof.

(i) That God's essence contains his existence.
(ii) The justification for God's essence containing his existence.

I was questioning (i), and I think you're talking about (ii). Taking them separately...

(i) Starts simply from the definition of God's essence as containing his existence, and from this it follows that if I have that essence, then God exists. Thinking about it clearly, that if is what stops the argument being circular. We have the following logic:

Proposition: God's essence contains his necessary existence.
Observation: God's essence is observed.
Deduction: God's existence is deduced.
Conclusion: God exists.

It isn't circular because it depends on the observation of God's essence. Descartes claims to make this observation, stating it as a clear and distinct (and so true) idea.

The triangle analogy is a case of intellectual dishonesty. Descartes takes a truism: a triangle has three angles adding to 180 degrees, and tries to give the truism the appearance of not being a truism by separating out the triangle into its essence and the property of having three angles adding to 180 degrees. Word play makes a truism appear like it might not be a truism.

He does the same but in reverse with God, taking an induction (the idea of God exists, therefore God exists) and appearing to make a truism (God's essence is that he exists). So this analogy isn't an analogy, for it holds only if God's essence and non-existence leads to a contradiction. It doesn't, unless one defines it to be. This leads to (ii): the justification, and to Descartes' first proof.

Last note on (i) is that, the extent to which the argument isn't circular is the extent to which it depends on observation, thus God's non-existence does not yield a contradiction so long as the observation is doubtful. I have good reasons to doubt it, thus the proof does not hold.


The justification for God's essence containing his existence is that God is most perfect, and that which is most perfect is most real, since non-existence would be a lack, an imperfection. If we accept Descartes' first proof, then the proposition of his second is justified, but then we do have a circular argument since the proposition depends on having established the necessity of God's existence in the first proof: God exists, therefore God exists.

So the second proof fails on two mutually exclusive points: (i) the argument is circular (the proposition is justified by proof 1), or (ii) the conclusion is underdetermined (the proposition is a definition).

The first proof, though, also underdetermines the conclusion. It goes something like this:
  • A thing can have no more objective reality than it does formal reality.
  • God is a perfect being, therefore lacks nothing.
  • Something lacking nothing is infinite: it cannot be added to.
  • Therefore God has infinite objective reality.
  • Therefore God has infinite formal reality.
  • Therefore God exists.
Descartes does not show he can grasp infinite objective reality, he merely shows that he can write the words. How much this proof relies on words (and, xris, more to the point, definitions) is evident if we change them slightly to see if the logic still holds but yields a different result. And indeed this is true, for instance:
  • A thing can have no more objective reality than it does formal reality.
  • God is a perfect carrot, therefore lacks nothing.
  • Something lacking nothing is infinite.
  • Therefore God has infinite objective reality.
  • Therefore God has infinite formal reality.
  • Therefore God exists.
  • Therefore, by definition, God exists as a carrot.
By changing the words I can, without contradiction, prove not only that God exists, but that he is a carrot. It is very easy to write words, much easier than to understand perfection, infinity, supreme beings, supreme carrots and the like. I can tell you I grasp God as an infinite carrot as easily as Descartes can tell you he grasps God as an infinite being; it does not follow that anyone has grasped anything beyond how to make sentences. It needs to be shown that someone has grasped an infinite being, rather than how to spell it, in order for his reasoning to have any general meaning, and it needs to be shown that only one such infinite being, having the character of God, is grasped in order to determine the conclusion.
 
xris
 
Reply Fri 15 May, 2009 08:29 am
@Bones-O,
Is more about who is making this claim rather than the notion.Sorry as i have not been educated in philosophy I might not be showing due reverence to the proposal.Objective evidence it appears is whats being claimed to be used, where in fact there is none.Its the logic of false premiss surely.A perfect red herring.
 
Bones-O
 
Reply Fri 15 May, 2009 09:54 am
@xris,
xris wrote:
Is more about who is making this claim rather than the notion.Sorry as i have not been educated in philosophy I might not be showing due reverence to the proposal.Objective evidence it appears is whats being claimed to be used, where in fact there is none.Its the logic of false premiss surely.A perfect red herring.

Hi xris. Descartes uses the terms 'objective' and 'formal' in pretty much the opposite way to the way we use them now. By 'objective', he means 'is an object of consciousness', what we would call a 'subjective' experience of something. By formal, he refers to the thing's fundamental, observer-independent structure (what we call objective) rather than the Aristotelian meaning of the word.
 
xris
 
Reply Fri 15 May, 2009 11:04 am
@Bones-O,
Bones-O! wrote:
Hi xris. Descartes uses the terms 'objective' and 'formal' in pretty much the opposite way to the way we use them now. By 'objective', he means 'is an object of consciousness', what we would call a 'subjective' experience of something. By formal, he refers to the thing's fundamental, observer-independent structure (what we call objective) rather than the Aristotelian meaning of the word.
Thanks for that but does that not make it even less meaningful to have a subjective view on a objectively viewed premiss.Objective,whose objective view? accepted by who as an objective value?
Let me see if i have it correct..I have by common knowledge been led to believe that Ghosts are invisible..therefore ghosts exist.Sorry if im not keeping up.Xris
 
kennethamy
 
Reply Fri 15 May, 2009 12:30 pm
@Theaetetus,
Theaetetus wrote:
David Hume brings up a nice counter argument that can be applied to Descartes. We are not justified in attributing more to God than we can gather from the environment. Because the world is imperfect, we cannot assume that God would be perfect. I don't know if that helps at all, but it is a good argument against the idea that God is a perfect being.



So, you are saying that if God were a perfect being, then God would exist? Of course, Hume's objection assumes that God created that world, and that since the world is imperfect, God is imperfect. I am not sure that is correct. A perfect being might have created an imperfect world because it would be impossible for such a Being to created a perfect world given what He had to work with.
 
Bones-O
 
Reply Fri 15 May, 2009 01:09 pm
@kennethamy,
kennethamy wrote:
So, you are saying that if God were a perfect being, then God would exist? Of course, Hume's objection assumes that God created that world, and that since the world is imperfect, God is imperfect. I am not sure that is correct. A perfect being might have created an imperfect world because it would be impossible for such a Being to created a perfect world given what He had to work with.

I don't think Hume was saying an imperfect world implies an imperfect God, but that an imperfect world does not imply a perfect God. In other words, there is nothing in the world that suggests a perfect God exists, so Descartes' assumption that God is perfect is unfounded.

---------- Post added at 02:16 PM ---------- Previous post was at 02:09 PM ----------

xris wrote:
Thanks for that but does that not make it even less meaningful to have a subjective view on a objectively viewed premiss.Objective,whose objective view? accepted by who as an objective value?

This is where Descartes assertion that something with subjective reality must have at least as much objective reality in the world or, confusingly, in his parlance, something with objective reality (an idea) must have at least as much formal reality (something that exists). Descartes admits that this formal reality may have more than one source: for instance, a unicorn has objective reality (there is an idea of a unicorn), and white horses and horns do have formal reality (they exist), even though unicorns don't. To Descartes, God cannot be described this way, presumably because something infinite would require an infinite number of finite real things, and we cannot know so much being finite beings, so the formal reality must also be infinite.
 
KaseiJin
 
Reply Fri 15 May, 2009 05:09 pm
@Bones-O,
Bones-O!;63218 wrote:

This is where Descartes assertion that something with subjective reality must have at least as much objective reality in the world or, confusingly, in his parlance, something with objective reality (an idea) must have at least as much formal reality (something that exists).


Yes. I am very much convinced by the average aggregate of evidence that we now have, that this is the very kingpin of the problem--the not realizing that that formal existence is exactly, and nothing more than, the formal reality of the activity of those physical things in his head, which did, in fact, exist when he was alive.
 
Bones-O
 
Reply Fri 15 May, 2009 05:31 pm
@KaseiJin,
KaseiJin wrote:
Yes. I am very much convinced by the average aggregate of evidence that we now have, that this is the very kingpin of the problem--the not realizing that that formal existence is exactly, and nothing more than, the formal reality of the activity of those physical things in his head, which did, in fact, exist when he was alive.

I don't know that that isn't something he grasped, since the distinction is still there - simply his terminology is counter-intuitive.

No takers on my not-God then no-idea refutation?
 
kennethamy
 
Reply Fri 15 May, 2009 05:53 pm
@Bones-O,
Bones-O! wrote:
I don't think Hume was saying an imperfect world implies an imperfect God, but that an imperfect world does not imply a perfect God. In other words, there is nothing in the world that suggests a perfect God exists, so Descartes' assumption that God is perfect is unfounded.

---------- Post added at 02:16 PM ---------- Previous post was at 02:09 PM ----------


.


Hume (of course) treats view that God is a perfect Being as empirical. But, it is not. It is a priori. Nothing could be God that was not perfect. Hume would consider that a "relation of ideas" and not a "matter of fact". But, that, of course, is not Descartes's view. He thinks that the statement that God is perfect is, what Kant would have called, synthetic a priori. Hume, of course, thinks there can be no such thing. To give Descartes a fair shot here we have to allow that God is a Perfect Being, is a necessary synthetic truth.

The real question, here is whether existence is a perfection (or a property). That's where the Achilles heel of the ontological argument is. And that is the assumption being made. Does God, in virtue of being a perfect Being have existence as an (essential) property? In general, when we say that X exists, are we saying that X has the property of existence, as contrasted with (say) mermaids, who do not?
 
KaseiJin
 
Reply Fri 15 May, 2009 07:20 pm
@Bones-O,
Bones-O!;63264 wrote:
I don't know that that isn't something he grasped,


It is most obvious that the guy did not have a good working knowledge of brain, therefore he wouldn't have grasped that idea. It is clear that his idea put the thoughts of the human brain into an immaterial world, different from that 'animal' portion of brain which controlled bodily functions and so on. (Animals did not have 'souls' in his views)

Therefore while I cannot formally do the logic (maybe I could with a little time investment, but I must back down from that...apologies there), I have enough information to conclude that that point in his Meditations was in error from the beginning, just as kennethamy has suggested...and was shifty.
 
kennethamy
 
Reply Fri 15 May, 2009 07:45 pm
@Bones-O,
Bones-O! wrote:
Cheers, Ken. You've raised some points I was also interested in.

I never believed in the triangle argument. Descartes compares the relation between the essence of God and God's existence with the essence of a triangle and the fact that its angles add up to 180 degrees. This analogy is false so far as I can see, insofar as the angles of a triangle adding up to 180 degrees is part of the essence of a triangle, not a condition of its existence, i.e. a triangle (a figure with three angles adding up to 180 degrees) may be conceived but possibly not experienced.

Your specific analogy here does not seem an analogy to me. I don't see how the idea of a winged horse not containing an existence truth value is analogous to a triangle having three angles, considering that a triangle is quite clearly, by definition and etymological deduction, something that has three angles.

But your argument is very much along the lines of Descartes' first proof of God's existence, and I'm open to discuss this, so long as the focus is not detracted from his second proof. Reason being that there is a relation between the two: Descartes' poses a relation between perfection and existence such that the thing that is most perfect is most real. This in itself is not only arguable, but probably worthy of reject, but assuming this point, God's existence still does not follow, for the reason of my second argument against Descartes' second proof. And, of course, the circular argument remains. I'm quite happy to ignore this point unless discussion depends on its consideration. I'm much more interested in if the circular argument may be true.

Thanks again people!

---------- Post added at 06:29 PM ---------- Previous post was at 06:16 PM ----------


Hello again Ken. Having read this, I'm wondering if my post was perhaps too subtle, or not forthright enough.

Descartes' argument is that if the idea of God, which contains his existence as true, then it follows that God's existence is true. It does not follow that since a perfect being may exist, there is a perfect being. It merely shows, if you accept such logic, that if a being is perfect, it must exist. One can state as easily as Descartes' states that God is perfect as God is not. And this is even before one approaches the question of whether that which is most perfect is most real, which is almost certainly not true.



Let's go back to Descartes's argument: But from the fact that I cannot think of God except as existing, it follows that existence is inseparable from God, and for this reason he really exists.

It seems to me that he is saying that his analogy between God existing, and the sum of the angles of a triangle being 180o is exact. Just as it is inconceivable that the sum of the angles should not be 180, so, it is inconceivable that God should not exist. "Inconceivable" here seems to me to mean something like, "self-contradictory". So the sum of the angles not equaling 180o is a necessary falsity, and so is God not existing a necessary falsity. And just as someone who has not studied geometry might think it possible for a triangle not to have angles which sum 180o, so, it might be possible for someone who has a confused idea of God to think that God might not exist. But that has to do with confusion, and not with the nature of a triangle, or the nature of God.

The issue concerns this analogy Descartes is drawing: the sum of the angles of a triangle = to 180 is a necessary property of a triangle; is existence a necessary property of God? Is it a property of God? Is existence a property (period)?
 
Bones-O
 
Reply Sat 16 May, 2009 05:48 am
@kennethamy,
Cheers Ken

kennethamy wrote:
It seems to me that he is saying that his analogy between God existing, and the sum of the angles of a triangle being 180o is exact. Just as it is inconceivable that the sum of the angles should not be 180, so, it is inconceivable that God should not exist. "Inconceivable" here seems to me to mean something like, "self-contradictory". So the sum of the angles not equaling 180o is a necessary falsity, and so is God not existing a necessary falsity. And just as someone who has not studied geometry might think it possible for a triangle not to have angles which sum 180o, so, it might be possible for someone who has a confused idea of God to think that God might not exist. But that has to do with confusion, and not with the nature of a triangle, or the nature of God.

But this is precisely my point: drawing an analogy between two things that aren't analogous is miseading. There is a contradiction in the statement 'this triangle has four angles'; there is no contradiction in 'God does not exist', except the contradiction of a person's faith. You seem to sympathise with the view that if one says there exists a contradiction where it is not yet shown to be true (since this is the subject of the proof), then there exists a contradiction.

The proof can be reworded thus and lose nothing:

1. God cannot not exist if I know he exists.
2. I know he exists.
3. Therefore he exists.

Does this strike you as defensible? Because when you get past the jargon this is all Decartes says.



[quote=kennethamy]The issue concerns this analogy Descartes is drawing: the sum of the angles of a triangle = to 180 is a necessary property of a triangle; is existence a necessary property of God? Is it a property of God? Is existence a property (period)? [/quote]

I'm happy for existence to be a property of an idea: I have an idea of a unicorn whose existence is false; I have an idea of the Lord Nelson monument who existence is true. But I have an idea of a triangle for which existence isn't a property, and an idea of God for whom existence is thought to be false.

We mathematically relate the angles and the sides of a triangle, defining it mathematically, and prove that its angles must add to 180 degs. We then find that whenever we measure and add up those angles, they sum to 180 degs. This is the basis of the property of the triangle: "it necessarily has three angles summing to 180 degs". So necessary properties are fine too.

What is the justification for God having the property of necessary existence that is analogous to the above?
 
xris
 
Reply Sat 16 May, 2009 06:17 am
@Bones-O,
Ide like a show of hands for those who think this meditation convinces them god exists.It is a play of words on the logic of illogical thinking.I think therefore i am.
 
kennethamy
 
Reply Sat 16 May, 2009 07:37 am
@xris,
xris wrote:
Ide like a show of hands for those who think this meditation convinces them god exists.It is a play of words on the logic of illogical thinking.I think therefore i am.



Whether an argument convinces anyone is not much of a criterion for whether the argument is a good argument or not. Convincing is a psychological, not a logical matter. It is the difference between proving something, and proving to someone. I might present a perfectly good argument to someone, which proves the conclusion, but I may still not be able to prove it to someone, for a number of reasons unconnected with th logic of the argument. He may not understand the argument; he may not want to accept the conclusion because it is inconsistent with some dearly held belief of his; and so on.

Thomas Aquinas pointed out, long ago, that very few people would be convinced by the ontological argument. And he said it was a weakness. But not a weakness in the logic of the argument. You have to show where the argument goes wrong (if it does). Not that it is not convincing.
 
xris
 
Reply Sat 16 May, 2009 08:30 am
@kennethamy,
kennethamy wrote:
Whether an argument convinces anyone is not much of a criterion for whether the argument is a good argument or not. Convincing is a psychological, not a logical matter. It is the difference between proving something, and proving to someone. I might present a perfectly good argument to someone, which proves the conclusion, but I may still not be able to prove it to someone, for a number of reasons unconnected with th logic of the argument. He may not understand the argument; he may not want to accept the conclusion because it is inconsistent with some dearly held belief of his; and so on.

Thomas Aquinas pointed out, long ago, that very few people would be convinced by the ontological argument. And he said it was a weakness. But not a weakness in the logic of the argument. You have to show where the argument goes wrong (if it does). Not that it is not convincing.
I understand the academic reasoning behind a debate but eventually a conclusion must be reached on its value as a logical means of determining.It appears to be the proposer has a certain validity and that it causes a constant round of intellectual discussion.If i had proposed this idea it would have been discounted almost immediately.The king has an opinion that must be observed.
 
kennethamy
 
Reply Sat 16 May, 2009 08:36 am
@xris,
xris wrote:
I understand the academic reasoning behind a debate but eventually a conclusion must be reached on its value as a logical means of determining.It appears to be the proposer has a certain validity and that it causes a constant round of intellectual discussion.If i had proposed this idea it would have been discounted almost immediately.The king has an opinion that must be observed.


Yes. We should try to decide whether the argument is a sound argument. But that cannot be decided by a show of hands. I don't know who the "king" is supposed to be. St. Anselm first in invented the argument in the 13th century, and Descartes revived it in the 17th century. Are they the "kings"? Most philosophers believe that ontological argument has been refuted. But not by a show of hands. (In fact, even in Descartes's time, several criticisms were offered. The criticisms of the logic were never, "I am not convinced", since that is not a relevant criticism of the argument).
 
 

 
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