Descartes’ Meditation III: Examining the Causal Argument for the Existence of God

© 2011

As Descartes closes his Second Meditation, the only thing he is certain of is that he is “a thing that thinks” and also, therefore, exists (Med II, paragraph 8). Now, in the Third Meditation, Descartes hopes to deduce and prove the existence of something greater than himself—in this case, God. In order to do so, Descartes establishes two different arguments for the possible existence of God. In his first attempt, known as the “Causal Argument”, he examines what exactly is necessary for something to be the cause of its own effect; his theories on the origin and conception of ideas are used to try and not only proving that God exists, but that he is the cause of himself. Something in this logic does not sit well with this writer: namely the belief that “no idea is in and of itself truer and has less of a basis for being suspected of falsehood” (Med III, paragraph 25). By stating that an idea cannot be conceived of by any being less than itself, Descartes limits the potential of the human mind and seemingly creates a circle of doubt and questioning; it is this circle which I challenge: the reasoning of the causal argument and the beliefs on conception of ideas can be called into question. First, I shall examine and define the terms which Descartes uses to create the base foundation for the causal argument and, second, I shall attempt to challenge the “Causal Argument” by examining the logic of the Cartesian Circle of Doubt within the definition of ideas.

The main point, or power, of the causal argument lies in Descartes assertion that whatever is contained objectively in an idea must be contained either formally or eminently in the cause of that idea. In layman’s terms: one cannot create the idea or truly conceive of anything that is greater than his or herself. Hence, Descartes states, it perfectly plausible that God must exist by that count as “[man] should not, however, have the idea of an infinite substance, seeing [he is] a finite being, unless it were given [him] by some substance in reality infinite” (III, 23), aka: God. This is the first place in which I am displeased with Descartes argument and assertions.

However, before any of the argument is to be examined, definitions must be made clear, starting with the very title of Meditation III: “Of God, That He Exists.” While Descartes constantly refers to God in most, if not all, of the meditations, he does not specify what exactly he means by the title: could God be no more than a metaphor or symbol of inexplicable phenomenon? Is it just the belief of something and/or anything that is greater than man itself? Whatever one might speculate, it is this title which allows for “God” to be, while not explicitly, at least implicitly defined: Descartes is dealing with the God of the Christians; the God of Aquinas and Pascal and the most powerful organization of the time, the Catholic Church. This is whom Descartes argues not only exists, but exists as “a substance infinite, independent, all-knowing, all-powerful” (III, 22).

What exactly is a substance to Descartes? A substance is essentially any particular thing that can exist by itself; therefore, a human body, a rock, or a pencil would all be substances—what he called “material substances” (II, 5). However, and here is where Descartes starts to get specific, these are only one type of substance; the other form of substances, known as “thinking substances”, can be demonstrated by such aspects as the human mind. What highlights the difference between these substances are the contrasting modes which “thinking substances” and “material substances” possess. The modes of any physical object—aka, “material substances”—would include aspects such as its location in space and time, its shape, and its volume; whereas the modes of a mind—aka, “thinking substance”—would include things like the specific ideas, judgments, and desires of the subject.

Descartes further organizes substances by saying that such things as human bodies, rocks, and pencils are not only material substances, but finite material substances. Similarly, human minds are not only thinking substances, but finite thinking substances. However, someone such as God would be, according to Descartes, considered an infinite substance. Infinite substances are utterly independent whereas finite substances are independent except for one dependence on an infinite substance. If there is to be a God, which Descartes asserts that there is, then God would be considered an infinite substance, and therefore also superior to finite substances (III, 23).

In order for substances to be substances, they must exist somewhere; this is where Descartes’ definitions of “reality” become important. There are two forms of reality: objective and formal reality. Objective reality contained in an idea is just the said idea’s representational content; essentially, it is the “object” of the idea or what that idea is about. For example, an idea of a pencil contains the reality of that pencil in it objectively. The formal reality contained in any one thing is a reality actually contained in that thing. This pencil, for example, has the formal reality of extension since it is actually an extended thing or body. In addition, reality is contained in something eminently when said reality is contained in it as a higher form such that not only does the thing not formally possess this reality, but it has the ability to cause that reality formally in something else. Not only do ideas represent things or substances, but they are themselves things; they are, in particular, modes of thinking substances. Thus, as every idea is a mode, every idea has some degree of formal reality.

Finally, one must have an understanding of what exactly Descartes’ definitions for ideas are. He separates them into two categories: “clear” and “distinct.” In his Principles of Philosophy, Descartes states that:

“A perception that can serve as the basis for a certain and indubitable judgment needs to be not merely clear but also distinct. I call a perception ‘clear’ when it is present and accessible to the attentive mind – just as we say that we see something clearly when it is present to the eye’s gaze and stimulates it with a sufficient degree of strength and accessibility. I call a perception ‘distinct’ if, as well as being clear, it is so sharply separated from all other perceptions that it contains within itself only what is clear” (45).

Between the two, a “distinct” idea appeals more to the particulars and details of any given object or substance, whereas “clear” refers mainly to its state of being. For example, say that I do not have my contact lens in—which hampers my ability to see distant objects real well—and there is a dog just far enough out of my vision that it appears blurry. I can have a “clear” idea that the object I see is a dog, however, I cannot have a “distinct” idea as to what breed the dog is until either (A) it moves closer to me, thus more sharply defining the image or (B) I place my contact lens back in and thus correct my inability to discern details.

But how exactly does one exactly have a “clear” and “distinct” idea of God? I cannot, with my very eyes, discern any “clear” or “distinct” idea of God as his form is not within my vision. If then, God is to be something which cannot be physically perceived, how can he at all be “clear” or “distinct” without being mere illusion or fabrication? Descartes would most likely cite my inability to perceive God as a result of the fact that I am a mere “finite” substance, whereas God is an “infinite” substance who exists beyond the realm of anything else and, as he states in paragraph 23 of the Third Meditation, “For though the idea of substance be in my mind owing to this, that I myself am a substance, I should not, however, have the idea of an infinite substance, seeing I am a finite being, unless it were given me by some substance in reality infinite.” As a result of being a finite substance, I am not only unable to fully perceive God’s existence, but there is no way he could be a fabrication of my own mind as I am unable to conceive of the idea of an infinite being on my own: it has to have been implanted by an infinite being.

If that is to be the case, then I have one question: what about the Ancient Greeks? They believed in and, as we now know, conceived of the idea of a great pantheon of gods and goddesses—as well as minor gods and goddesses which, for the sake of argument, shall be paralleled to the Christian hierarchy of angels—all of which can be determined to be greater than mere humanity. As humans, we are unable to perform the tasks which these beings accomplished: changing shape at will, controlling the weather, life and death, etc etc. Therefore, it can be affirmed that these beings were greater than that of humans. They existed beyond the realm of anything else and, thus, could be considered “infinite” substances. However, as was known by Descartes’ time: the Greek pantheon was not only declared false, but heretical. So, how is it that Ancient Greeks were able to conceive of these gods and goddesses? According to Descartes’ logic, if these beings are “infinite” substances, then humans cannot have conceived of these gods and goddesses on their own.

As no idea can have “nothing” as its cause, and, as “finite” substances, the Ancient Greeks themselves could not have conceived of their pantheon on their own, it can only be concluded that God is the cause of this idea. In that case, would that not make God a deceiver? Descartes already spent almost two and a half different meditations reiterating and reaffirming that God, should he exist, is not some “evil demon” or “evil genius” bent on creating mischief (I, 9-12). Therefore, there must a flaw in the logic of his argument. Consider the possibility that man could actual strip away all the restrictions that comes from being a “finite” substance and was able to conceive of things that could be considered “infinite” substances: man would have a plethora of original, larger-than-life ideas which were created from his very own mind; man would be able to be the cause of the belief in the existence of God. In a sense: man will have created God from his own mind.

Descartes’ “Causal Argument” for the existence of God, while long and detailed, lacks in it a faith in man’s own imaginative power and ability to perceive and conceive beyond himself and his own existence. It is this lacking and Descartes’ almost aggressive insistence that there is no possible way that God could not exist which creates small holes in his own Cartesian circle of doubt. If he simply allowed for man to conceive of “infinite” substances or even accept that perhaps there is a God out there who wishes to deceive mankind on some level, this passage might hold more weight.



Descartes, Renee. “Meditations on First Philosophy.” Modern Philosophy: An Anthology of Primary Sources. Ed. Roger Ariew & Eric Watkins.  IN: Hackett, 2009. 35-68.

—. “The Principles of Philosophy, Part I.” The Philosophical Writings of Descartes, Vol. 1. Trans. John Cottingham, Robert Stoothoff, and Dugald Murdoch. Cambridge:  Cambridge University Press, 1985.

“Descartes’ Ontological Argument.” Stanford Encyclopedia of Philosophy. <;

Flage, Daniel E. and Clarence A. Bonnon. “Meditation Three: Reaching the peak, or variations on the existence and idea of God.” Descartes and Method: A Search for Method in Meditations London: Routledge, 1999. pp. 166-202 and 280-284.


2 thoughts on “Descartes’ Meditation III: Examining the Causal Argument for the Existence of God

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s