A Stanford Encyclopedia Entry on Descartes' Ontological Argument

The author argues that Descartes can rebut all the easy refutations, but doesn't necessarily endorse the argument.

If Descartes had only known

This explains the difference between being awake and dreaming. But I suppose it is not sufficient to reassure us if we think we're brains in vats.

Ht: Rosa Ortiz.

Some lecture notes on Descartes

Since we will soon be starting Descartes today in Philosophy 101, I thought I would put some notes I wrote up about him on the blog. Comments and dialogue welcome of course.

Rene Descartes
I. The Impact of Modern Science
II. Three Goals
A. Find Certainty
B. Establish science on a firm foundation
C. Reconcile science and religion
III. Uncertainty about beliefs caused by intellectual, ecclesiastical, and political upheaval
A. Intellectual upheaval: Change from a geocentric view to a heliocentric view (the sun, not the earth is the center of everything)
B. Ecclesiastical upheaval: Instead of one Church in control of everything, Europe is divided between Catholics and Protestants
C. Political upheaval: Descartes time saw the rise of the modern state, and the colonization of the Americas. It also saw 30 years of war over religion, resulting in the slaughter of 1/3 of the population of Europe.
IV. Threat of materialism and determinism
A. Modern science moves in the direction of viewing the world as a machine
B. But if the world is a machine, and we are just one more part of the world, then we are machines
C. If we are machines, then whether we do right or do wrong is a function of how we were programmed. Given the basic laws of the universe and the initial positions of the atoms, we could not have done otherwise from what we did.
D. If we could not have done otherwise from what we did, then the idea of sin makes no sense. We are not, in any significant sense, responsible for our actions. What’s worse, if you assume there’s a God, the God is responsible for all of our worst sins. This does not seem compatible with the idea of a perfectly good God.
V. The Jesuit solution: The Protestants, for example, maintained that it was possible to doubt the truth of the Church’s teaching by appealing to the Bible. At the Jesuit school that Descartes attended, they taught him that this would result in an unending chain of doubts. You can doubt the Church on the basis of the Bible. You can doubt the Bible on the basis of science. You can doubt science on the ground that it appeals to sense experience, which can be doubted. Once the spiral of doubt starts, it can’t be stopped. So just believe what Mother Church tells you to, and don’t ask so many questions.
A. Descartes is not satisfied with the Jesuit Solution. However, he does learn something from the Jesuit method. But he develops the method of universal doubt not to undermine confidence and force reliance on the authority of the Church, but to discover what he can really be sure of.
VI. Two models of knowledge: The house model and the boat model. According to the house model, what makes a belief system stad up is its foundation. If a house is shaking, tear it down, put in a secure foundation, and build it up again. On the boat model (attributed to Neurath), we have to replace planks as necessary, but tearing the whole boat apart would be a mistake that would cause the boat to sink.
VII. Method of doubt: Doubt everything that can possibly be doubted, not simply what can reasonably be doubted.
A. Sense experience and the Dream Conjecture. Could I really be dreaming? Well what if I pinch myself. But then I could be dreaming the pinch. So I pinch myself again, and again, and again, until I really do go unconscious and start dreaming!
B. Mathematical Truths: Descartes introduces the Evil Demon conjecture. Is it possible that SATAN IS CONTROLLING YOUR MIND? (Perhaps you have been listening to too much rock music, with Satanic lyrics put in backwards, and now SATAN IS CONTROLLING YOUR MIND). Well, what Descartes means is an omnipotent being (unlike the fallen angel Lucifer) who is dedicated to deceiving everyone as much as possible. In order to discover what we can really be sure of , Descartes introduces the Satan Test. Something can be included in the foundations of knowledge only if, even on the assumption that Satan is controlling your mind, and wants to deceive you as much as possible, you can be sure that this belief is true.
C. Can anything pass the Satan test? Surely not the knowledge that Bush is President. That could be a media hoax. Or your belief that you are now sitting in a chair? A piece of cake for the devil. How about math? Descartes says that perhaps 2 + 2 = 5, but Satan has deceived you into thinking that 2 + 2 = 4. (I have my doubts about his position on this one, but let’s give the man the benefit of the doubt.)
D. How about the belief that I am now thinking. Could Satan deceive me into thinking that I am now thinking? Well, if he DECEIVED me into thinking that I am now thinking, then I would have to not be thinking. On the other hand, if I had the deceptive thought that I am now thinking, I would have to be thinking. The idea that I am now thinking is indubitable, because a contradiction emerges when I attempt to consider that possibility of being deceived about it.
E. What about the belief that I exist. Well, if I can be sure that I am thinking, then it follows that I exist. Or, as you no doubt heard before you ever took Philosophy, “I think therefore I am.” Although you may have heard it a million times (in fact it’s a great thing to say after a few beers if you want to impress someone with how deep a thinker you are-NOT), this is what it means in its original context. “I think” and “I exist” pass the Satan test, because even on the assumption that Satan is controlling my mind, he can’t possibly deceive me about these two claims.

Keith Parsons thinks the objection isn't so overrated

A redated post.

Keith Parsons thinks the argument is not so overrated. See these comments in a two-journal exchange with me:

It will simply not do far Hart (or Reppert) to take refuge in familiar Humean conundrums about causality. Much of the progress of science has been progress in understanding how things interact: Plate Tectonics tells us how crustal plates interact to produce earthquakes, volcanoes, mountains and other geological phenomena. Likewise, ecology helps us to understand the enormously complex interactions with their physical environment and each other. Molecular biology explains the interactions of complex molecules, e. g. enzymes and their substrates. Even at the rock-bottom level of quarks and gluons we have well-confirmed, mathematically precise theories that often make (as in Quantum Electrodynamics) astonishingly accurate predictions. These theories tell us how fundamental particles interact.
Keith M. Parsons, "Further Reflections on the Argument from Reason" Philo (Spring-Summer 2000), 93.

As Lycan notes above, Descartes took this objection seriously, and he should have. Surely dualists owe the rest of us some sort of account. After all they posit and entity that has no physical properties (and consequently is undetectable by any empirical means), but which is not an abstract entity since it somehow interacts with physical things—in a way that violates conservation laws, by the way. Souls could not have been produced by physical means, and their putative existence raises a host of unanswerable questions. (For example, at what point at the evolution of hominids did our ancestors acquire souls? Homo habilis or Homo erectus, maybe).

Keith M. Parsons, "Need Reasons be Causes? A Further Reply to Victor Reppert's Argument from Reason", Philosophia Christi (Vol. 5, No. 1, 2003) pp. 72-73.

An overrated objection to Cartesian dualism

A redated post.

William Hasker, who is not a Cartesian dualist, thinks so.

The hoariest objection specifically to Cartesian dualism (but one still frequently taken as decisive) is that, because of the great disparity between mental and physical substances, causal interaction between them is unintelligible and impossible. This argument may well hold the record for overrated objections to major philosophical positions. What is true about it is that we lack any intuitive understanding of the causal relationship between Cartesian souls and bodies. And there is no doubt that, other things being equal, a mind-body theory that allowed such understanding would seem preferable to one that did not. The reason this is not decisive is that, as Hume pointed out, all causal relationships involving physical objects involving physical objects are at bottom conceptually opaque. We find the kinetic theory of gases, with its ping-pong-ball molecules bouncing off each other, fairly readily understandable. This, however, is only because we have learned from experience about the behavior of actual ping-pong balls, and our expectations in such cases have become so habitual that they seem natural to us; we have no ultimate insight into the causal relations except to say, “That’s the way things are.” But equally and emphatically, “the way things are” includes the fact that our thoughts, feelings, and intentions are affected by what happens to our bodies, and vice versa, and to deny these palpable facts for the sake of a philosophical theory seems a strange aberration.

William Hasker, The Emergent Self (Cornell, 1999) p. 130.

Frank Dilley's defense of Cartesian Dualism

Descartes on dualism and the physical world

Justifying the physical world
Descartes’ argument for the reality of the physical world is this
We have experiences of various things which we take to be physical objects.
Either these experiences refer to real objects, or some powerful being is causing me to falsely believe them.
If some powerful being is causing me to believe these things, then that being is a deceiver and is not a good being.
However, I have proved that a perfect being exists and is all-powerful.
Such a perfect being would not deceive me, and would not permit a less powerful being to deceive me in such a massive way.
Therefore, the experiences are not deceptions, and physical objects really do exist.
Some questions about this
If God is omniscient, omnipotent, and perfectly good, then on the face of things God should not allow physical evil (suffering) as well as intellectual evil (error or false beliefs).
But there is physical evil and intellectual evil. Therefore either an omnipotent, omniscient and perfectly good being doesn’t exist, or He (or She) has a good reason for permitting both physical and intellectual evil.
Therefore, either God does not exist, or God’s existence is compatible with the existence of intellectual evil.
But how massive a deception is possible if there’s a God?
Descartes perhaps thinks that God’s existence is incompatible with really massive and systematic intellectual evil, such as we would have if we were deceived about the existence of the physical world.
But there are some people down on 24th and Van Buren (the local mental hospital in Phoenix) who think they are poached eggs, or think that they are Napoleon, or think they’re Jesus Christ.

Our belief in the physical world
Descartes does point out that physical objects are not always as they appear to the senses.
However our minds have the ability to overcome the defects of sensory knowledge. For example, even though a straight stick in water appears to the eye to be bent, we nevertheless can figure out that it really is straight.
Descartes on physical things
Physical things “possess all the properties which I clearly and distinctly understand, that is, all those which, viewed in general terms, are comprised within the subject-matter of pure mathematics.”
Descartes and Galileo
A. Descartes is supporting Galileo’s view that the real nature of the physical world is mathematical. The objective properties of an object are the properties that can be given a mathematical description, such as size, shape and motion. Colors, tastes, sounds and all the other qualities of our experience are in the mind but not in objects themselves. The world as it is in itself is colorless, but it has the tendency to produce in our minds a sense of it being this color or that color.
The mind-body relation
Descartes accepts the medieval (and Aristotelian) conception of substance.
At first he defines substances as something that exists in such a way as to depend on nothing for its existence. This definition would mean that only God is a substance.
But other substances are call that by analogy.
There are two types of substances: mental substances and physical substances. This implies that the mind and the body are two completely different entities.
Why they are so different
The body can be doubted but the mind cannot be doubted.
Minds have complete different attributes than physical things
1. Bodies take up space and are move by physical forces.
2. Minds do not take up space and are a kind of nonphysical or spiritual reality.
3. Minds are not made up of parts and cannot be divided.
How are these types of reality linked together
The body is a machine made out of flesh and bone.
All animals but humans are just machines.
Thus you can’t really be cruel to animals, since they don’t really have any feelings. (This puts Descartes in the PETA hall of shame).
C. Your mind is the real you. You don’t have a mind you are a mind. You have a body.
Cartesian Dualism
Cartesian dualism is a metaphysical dualism. It is also a mind-body dualism. There are two irreducible types of realities.
By means of this kind of dualism, Descartes hoped to effect a compromise between religion and science. One part of reality, the physical part, can be analyzed by physical methods. It is an entirely clocklike mechanism, governed by the laws of nature, with no purpose whatsoever. The other part of reality, the mind, has freedom to think and will as we wish, and is not under the control of physical law.
In the physical realm, science is the authority and gives us the truth, but it tells us nothing about the eternal destiny of our souls, only about our bodies. In the spiritual realm, religion remains authoritative.
Relating the two realms
There remains, however the issue of how these two realms were related. If I commit a murder, I may begin with a homicidal thought, which presumably exists in my soul, but then that homicidal thought has to result in my brain sending a message to my trigger finger to go ahead and fire and leave my victim in a pool of blood. In order for this to be even possible, there has to be some kind of causation between the mental realm and the physical realm. Therefore, if Cartesian dualism is true, it is not quite the case the physics fully explains the physical. It fully explains the physical unless the mental interferes with it.
How do they interact?
Descartes further is faced with the problem of how the mental realm and the physical realm can interact, since they are so different. As Lawhead’s text says “The mind has no gears of muscles or chemicals by which to move other things or to be moved.”
Descartes’ solution makes things worse. He suggests that the pineal gland at the base of the brain, which at the time no one knew what it did, and that the pineal gland was affected by “vital spirits.” But this really doesn’t solve the problem.
An overrated objection?
William Hasker, who is a contemporary dualist (but a dualist of a different kind from Descartes) argues that this objection is overrated. He writes:

Hasker’s response
The hoariest objection specifically to Cartesian dualism (but one still frequently taken as decisive) is that, because of the great disparity between mental and physical substances, causal interaction between them is unintelligible and impossible. This argument may well hold the record for overrated objections to major philosophical positions. What is true about it is that we lack any intuitive understanding of the causal relationship between Cartesian souls and bodies. And there is no doubt that, other things being equal, a mind-body theory that allowed such understanding would seem preferable to one that did not. The reason this is not decisive is that, as Hume pointed out, all causal relationships involving physical objects involving physical objects are at bottom conceptually opaque. We find the kinetic theory of gases, with its ping-pong-ball molecules bouncing off each other, fairly readily understandable.
Hasker continues
This, however, is only because we have learned from experience about the behavior of actual ping-pong balls, and our expectations in such cases have become so habitual that they seem natural to us; we have no ultimate insight into the causal relations except to say, “That’s the way things are.” But equally and emphatically, “the way things are” includes the fact that our thoughts, feelings, and intentions are affected by what happens to our bodies, and vice versa, and to deny these palpable facts for the sake of a philosophical theory seems a strange aberration.
Keith Parsons disagrees (in a two-journal exchange with me)
It will simply not do for Hart (or Reppert) to take refuge in familiar Humean conundrums about causality. Much of the progress of science has been progress in understanding how things interact: Plate tectonics tells us how crustal plates interact to produce earthquakes, volcanoes, mountains, and other geological phenomena. Likewise, ecology helps us to understand the enormously complex interactions of organisms with their physical environments and each other. Molecular biology explains the interactions of complex molecules, e.g. enzymes and their substrates. Even at the rock-bottom level of quarks and gluons we have well-confirmed, mathematically precise theories that often make (as in Quantum Electrodynamics) astonishingly accurate predictions. These theories tell us how fundamental particles interact.
Another Parsons comment
Descartes took this objection seriously, and he should have. Surely dualists owe the rest of us some sort of account. After all they posit and entity that has no physical properties (and consequently is undetectable by any empirical means), but which is not an abstract entity since it somehow interacts with physical things—in a way that violates conservation laws, by the way. Souls could not have been produced by physical means, and their putative existence raises a host of unanswerable questions. (For example, at what point at the evolution of hominids did our ancestors acquire souls? Homo habilis or Homo erectus, maybe As Lycan notes above, Descartes took this objection ).

Alternatives to Interactionism (Descartes didn’t buy these)
Geulincx said that mental events and physical evens are independent processes that only seem to influence one another. But actually God arranges two parallel series of mental and physical events. This is parallelism
Malebranche said that each type of event is an occasion on which God produces correlated events in the other realm. This is occasionalism.

More Descartes Lecture Notes

The Clear and Distinct Criterion
I am inclined to agree, even though some people don't, that Descartes successfully proves that "I think" and "I exist are immune from doubt. But then Descartes does something that strikes me as weird. First, he asks himself how he became convinced of the conclusion of the cogito argument and concludes that he accepts it because he clearly and distinctly perceives it to be good.
Justifying the criterion
Hey wait a minute Descartes? Didn't you just produce a self-refutation argument against the claims "I do not exist" and "I do not think." As a result he claims this supports his clear and distinct criterion. Then he considers whether or not God exists, and he does this in order to reassure himself that his clear and distinct perceptions are not Satanic deceptions. But to do this, it seems to me that the premises of his arguments have to be premises he can be sure of, even if Satan is controlling his mind. This argument, the argument based on the cause of his idea of God, fails to achieve this, even if it were a good argument (and I don't think it is a good argument).

The Circularity charge against Descartes
Critics of Descartes accuse him of arguing in a circle. They claim that the reason he can accept the existence of a nondeceptive God in order to believe be sure that ideas that seem clear and distinct are really true. But is his case for God based on the presupposition that whatever he clearly and distinctly perceives to be true really is.

A different complaint?
My complaint is a little different, in that it doesn’t rest on the idea that he is using the clear and distinct criterion to justify the premises of the argument.
I think my objection rests on the assumption that Descartes needs to refute demon-scenario objections to beliefs in order to have any justification at all for believing them. What is seems impossible to have is an argument for the existence of God that is based entirely on Satan-tested premises.

Descartes’ argument for God
At the very least Descartes can’t try to prove God with experience-based premises, which is what Aquinas did. Descartes has to work from the contents of his own mind. So his first argument is a cosmological argument, but what has to be caused are ideas in his mind, not the physical universe.

The Cartesian Cosmological Argument
1. Something cannot be derived from nothing. In other words, all effects, including ideas, are derived from something.
2. There must be at least as much reality in the cause as there is in the effect.
3. I have an idea of God (as an infinite and perfect being).
4. The idea of God in my mind is an effect that was caused by something.
5. I am finite and imperfect, and thus I could not be the cause of the idea of an infinite and perfect God.
6. Only and infinite and perfect God could be the cause of such an idea.
7. Therefore God (an infinite and perfect being) exists.

Criticisms of the Cartesian Argument
1. If Descartes is going to be so skeptical about everything he believes, why does he accept certain principles like that which is found in premise 1 or in premise 2.
Some things, Descartes thinks, can be believed because the “light of nature” guarantees that they are true.
He wants to distinguish between natural impulses and the light of nature, but how can he do this? What criteria do you use for making the distinction?
2. Why doubt this and not that?
Descartes used the demon conjecture to doubt whether basic mathematical truths like 2 + 3 = 5 were true, but did not doubt that the principle “there must be at least as much reality in the total efficient cause as in the effect” was true.
3. Could we have invented the idea of God?
Some theologians of Descartes’ time thought that we could build the idea of God ourselves without God having given it to us.
“I can surely take a given degree of being, which I perceive within myself, and add on a further degree, and thus construct the idea a perfect being from all the degrees which are capable of being added on.”

The second Cartesian cosmological argument
Descartes says that his own sustained existence requires an adequate cause. A being like himself who contains the idea of perfection could not have come from an imperfect cause. There cannot be an infinite regress of causes, so God must exist to cause his existence

Descartes’ Ontological argument
Descartes uses a version of the ontological argument for the existence of God, which was first introduced by St. Anselm but rejected by Aquinas.

The OA
1. I have the idea of a God that possesses all perfections (good qualities). Existence is a kind of perfection.
If the God I am thinking of lacked existence, then he would not be perfect.
Hence, if I have the idea of a perfect God, I must conclude that existence is one of his essential properties.
If existence is one of his essential properties, he must exist.
Therefore, God exists.
The Problem of Error
While he takes his argument to overcome the problem of demon skepticism, he must overcome the opposite problem
If God supports our rationality, why do we make so many mistakes.
“So what then is the source of my mistakes? It must be simply this: the scope of the will is wider than that of the intellect; but instead of restricting it within the same limits, I extend its use to matters which I do not understand. Since the will is indifferent in such cases, it is easily turned aside from what is true and good, and this is the source of my error and sin.”

My complaint with Descartes

I would like to have an interpretation of Descartes' work that does not charge him with a huge error. I'm not sure my charge is exactly the circularity charge that DePoe is struggling with but here is how it goes.

I am inclined to agree, even though some poeple don't, that Descartes successfully proves that "I think" and "I exist are immune from doubt. But then Descartes does something that strikes me as weird. First, he asks himself how he became convinced of the conclusion of the cogito argument and concludes that he accepts it because he clearly and distinctly perceives it to be good. Hey wait a minute Descartes? Didn't you just produce a self-refutation argument against the claims "I do not exist" and "I do not think." As a result he claims this supports his clear and distinct criterion. Then he considers whether or not God exists, and he does this in order to reassure himself that his clear and distinct perceptions are not Satanic deceptions. But to do this, it seems to me that the premises of his arguments have to be premises he can be sure of, even if Satan is controlling his mind. This argument, the argument based on the cause of his idea of God, fails to achieve this, even if it were a good argument (and I don't think it is a good argument).

1. Something cannot be derived from nothing. In other words, all effects, including ideas, are derived from something.
2. There must be at least as much reality in the cause as there is in the effect.
3. I have an idea of God (as an infintie and perfect being).
4. The idea of God in my mind is an effect that was caused by something.
5. I am finite and imprefec t, and thus I could not be the caue of the idea of an infinite and perfect God.
6. Only and infinite and perfect GOd could be the cause of such an idea.
7. Therefore God (an infinite and perfect being) exists.

What is the most charitable way to read this?

I think therefore I am

Now that we understand (assuming we do) the context of Descartes' famous "I think therefore I am" argument, we might want to know if it does what Descartes thinks it has done. Does it really remove all possible doubt from the propositions "I think" and "I exist"?

One possible response would be to say that you could just as easily say, as in the Monty Python philosopher's drinking song, I drink therefore I am. But "I am drinking" clearly does not pass the Satan test. Satan could deceive me into thinking that I am drinking; in fact, beer could do the same thing. Enough Miller Genuine Draft will cause you to pass out, in which case you may dream of more MGDs even though they don't exist.

But does Descartes prove that there is a something that does the thinking, as opposed to just that thinking is going on? The Stanford Encyclopedia of Philosophy says:

Many a critic has complained that in referring to the "I" Descartes begs the question, since he presupposes what he intends to establish in "I exist." Bertrand Russell objects that "the word ‘I’ is really illegitimate"; that Descartes should have, instead, stated "his ultimate premiss in the form ‘there are thoughts’." As Russell adds, "the word ‘I’ is grammatically convenient, but does not describe a datum." (1945, 567) Accordingly, "there is pain" and "I am in pain" have different contents, and Descartes is entitled only to the former.

But my problem with this objection is that just because we can say "there are thoughts" and not actually say that someone is thinking those thoughts doesn't make the suggestion coherent. As Russell should have known, you can say "Floyd the barber shaves everyone who doesn't shave himself in Mayberry," but only when we ask whether Floyd shaves himself do we discover that the suggestion is not coherent. Does the term "pain" really mean anything if there is no one experiencing the pain? We can redescribe the pain in such a way that it no longer refers to an individual having the pain, (the firing of C-fibers in the brain) but if we do it seems we lose what is meant by pain. (This would be a good way to solve the problem of pain, if it were legitimate. "You think these people are suffering terrible pain, and that God shouldn't allow it. But really all that is going on is that people's C-fibers are firing.)

In short, I think that Descartes argument that there must be a thinking subject is a successful argument. It's the next stages of Descartes' programme that I have trouble with.