Descartes vs. Berkeley: On the Two Corners of the Triangle


Descartes vs. Berkeley

On the Two Corners of the Triangle

Edip Yuksel

Mind, body and God! This is a Bermuda Triangle which philosophers have been struggling with for centuries. They have demonstrated positions ranging on all possible combinations and permutations: All three exist… Only mind exists… Mind and body exist, while God is created by our mind… Body is the essence and mind is a function of the body… Only universal spirit, that is God, exists… Mind is the first… No, body is the first… Neither, God is the first… So on so forth… Here we will demonstrate, compare and contrast the opinions of Descartes and Berkeley on the interaction and relation between the two corners of the triangle: Mind and God.


Descartes, by employing his unique method of extreme doubt tried to find a fundamental truth, knowledge that he could be certain about. As a result he was sure that he, as a doubting thinker, must exist. This simple claim was a revolutionary armor against extreme skepticism. Here, he does not try to prove to others that he (Descartes, as a mind) exists. But he forces the extreme skeptics to acknowledge their own existence as an unavoidable consequence of their very doubt.

Ironically, we see this extremely cautious Descartes embracing the other two questioned concept that is God and body. He uses the rock-solid knowledge about his mental existence as a proof for the existence of God, and then uses the existence of God as a proof for the existence of physical world, or body.

He suggests two reasons for the existence of God.

1. Though, he proves the existence of self, yet, he cannot accept this doubting finite self to be the guarantor of its own existence. Therefore, his existence needs a Creator. This Creator should be a Conserver too, since the continuity of created beings needs the continuity of the initiating power.

2. He claims that having the idea of “Infinite Perfect Being” requires the independent existence of that idea. To him, having the idea of infinity without witnessing such a thing implies the existence of God. Since finite self cannot generate the idea of infinite being, the idea must come from somewhere, from Infinite Being himself.

Then, he introduces God as a reliable warrant for our ideas about the external world or body. “If God is perfect, which he is, then our ideas must be clear and distinct. God won’t deceive us while we are trying our best.” Descartes thought that God created material substance with geometric properties. Thus, in Cartesian doctrine, the sequence of proving the existence of three independently existing being (substances) is: mind, God and body, respectively. To Descartes, the existence of body can be proven only by accepting the existence of an Infinite and Perfect Being. Only God can eliminate the probability of sensory illusions or evil demons. In Descartes’ own words:

“From this it is quite clear that, notwithstanding the supreme goodness of God, the nature of man, inasmuch as it is composed of mind and body, cannot be otherwise than sometimes a source of deception.” (A History of Wester Filosophy, W. T. Jones, H.B.J, 1980, Vol: 3, p. 185).

Furthermore, for Descartes, God is the only solution for the problem of interaction between the two substances (mind and body) which do not have overlapping properties.

The problems:

1. If Descartes had stayed loyal to his method which enables him to reach absolute certainty he could not have gone beyond proving his self-existence. He uses reasoning to prove the existence of God, which in turn, knocks-out the evil demons. However, the evil demons won’t let this to happen if Descartes had granted them the credit which they deserve by his own definition. The evil demons may have had worked on Descartes’ mind which led him to think of the existence of an Infinite and Perfect Being.

In other words, in order to have a clear and distinct idea he needs the existence of the Perfect Being. However, the idea of this “need” by itself is questionable. He rests the clarity of his ideas on God, but before that, he rests God on those ideas. He “proves” the existence of God with suspected ideas. This is a circular argument.

2. Gaunilon’s objection based on the example of perfect island (Lost Island) indicates another problem with Descartes’ proof of God’s existence which is based on the existence of the idea of Infinite Perfect Being in our mind. We can entertain the idea of many things which do not exist in reality. Greek gods and goddesses are good examples.

However, a counter argument can be suggested: Those fictitious ideas exist in parts. For instance Pan, the Greek god who is pictured as half man half goat, in fact, exists in parts. Man and goat exist separately. Similarly, the parts that create the all perfect island exist in reality. Perfection also exists as an independent concept of quality. The composition of parts (the all perfect island) may not exist, however, its each individual part or concept must exist. We cannot think of non-existing parts nor concepts. Our mind can only arrange them in different combinations.

God is not consisted of parts like the “Lost Island”. God is the equivalent of the concept of “Infinite Being”, which is one substance. If we can think of the existence of that indivisible substance, then it must exist as a whole. Therefore, the “Lost Island” is not analogous to “God”.

3. Hobbes objects to Descartes by saying that we don’t have the concept of infinity, or perfection, or God. We cannot comprehend their implied meanings. They are meaningless words.

However, this objection is also can be countered by the following argument: Your inability to comprehend infinity or perfection does not necessarily mean that such a concept does not exist. When you say that you are not able to comprehend the meaning of infinity, in fact, by this very statement you acknowledge that you understand the implication of the word (its meaning), and also understand that you are not able to comprehend it with your three-pound brain. In other words, you can understand the “infinity” as the antonym of finite, not as the extremely extended finite. As a matter of fact, many of us do not comprehend many things but accept their existence, such as TV, computer etc. The concept of “infinity” is not like “ojofuffo”. You know the meaning of infinity but you cannot comprehend it. But, you neither know the meaning of “ojofuffo”, nor you can comprehend it. Whenever you assign a meaning to “ojofuffo”, you relate it to an already existing concept, and it comes into the universe of existence.

4. Descartes, by claiming that mind and body owe God their existence, disqualifies both from being substances, since by definition, substances are independent for their existence. Hence, when mind and body are fired from being substances they become integrated with God. Obviously, this leads to pantheism which contradicts the Judeo-Christian concept of sin and the responsibility of human beings.


Berkeley, like Descartes, tries to avoid skepticism. He wants to attain certainty. Thus, he adopts Descartes’ “cogito.” Berkeley argues that sensible properties are the property of the mind, not objects. He does not accept two different notions of properties as Descartes suggested. According to Descartes every substance has two kinds of properties. Primary: the essence of existence, such as the geometric shape of objects, velocity, position. Secondary: sensory properties, such as colors. When Berkeley examined his perception of things he came to the conclusion that whatever information he has all are secondary properties, which are functions of his mind. Thus, Berkeley rejects the existence of primary qualities, in other words, the existence of physical world as a substance. To him, mind is the only substance, and ideas are attributes of mind which develops through personal experience. He cleverly, reduces the matter to mere noise.

“Now, why may we not as well argue that figure and extension are not patterns or resemblances of qualities existing in Matter; because to the same eye at different stations, or eyes of a different texture at the same station, they appear various, and cannot therefore be the images of anything settled and determinate without the mind?” (Ibid, Vol: 3, p. 282).

Instead of the word “matter” he suggests “sensible things,” which he defines as collection of sensible qualities which are immediately perceived. There is no such a thing mind-independent objects.

However, Berkeley is compelled to make an exception in his mind-independency principle. He needs God as the cause of orderly and regular but “visibly inactive” ideas he has. He thinks that “matter” as an empty word cannot be the cause of ideas. By eliminating “matter” from the triangle he departs from Cartesian doctrine. This difference saves Berkeley from the problem regarding the interaction between mind and body.

Both, Descartes and Berkeley, insert the concept of God into their argument by introducing God as the CAUSE of our ideas. But, they differ dramatically. According to Descartes, God is the only possible cause of the IDEA OF GOD. Matter is the cause of other ideas. God, in this case, is a controller against complete deception.  But, according to Berkeley’s original doctrine, God is the only possible cause of ALL IDEAS.

“If we attentively consider the constant regularity, order, and concatenation of natural things, the surprising magnificence, beauty and perfection of . . . I say if we consider all these things, and at the same time attend to the meaning and import of the attributes One, Eternal, Infinitely Wise, Good, and Perfect, we shall clearly perceive that they belong to the aforesaid Spirit, ‘who works all in all’ and “by whom all things consist.” (Ibid, Vol:3, p. 291).

Though Berkeley claims that “being is to be perceived”, he does not claim that sensible things vanishes when he does not perceive them. He asserts that the collections of sensible things are always in God’s mind so they do not cease to exist when he does not perceive them. God has the correct information of sensible things. To him, God as a Divine Mind is the source of our ideas and of perpetual existence of sensible things.


1. I would like to ask Berkeley the following question: When you close your eyes you don’t see. Do you close an idea when you close your eyelids, or do you eliminate a material medium? His answer would be: “My eyes are sensible properties; they are tactile perceptions in my mind. I don’t have material eyes. Closing my eyes is a mental decision which has its unique mental consequences.” Obviously, this is a good answer.

Now, let’s modify my question: How do you explain if “I” close your eyes with my hands while you are not aware of it? Am I interfering your mind or closing your material eyes? Berkeley would deny my existence by saying that his mind randomly shuts down some of his sensory perceptions. But, if I show him that “I” can predict these random mental events he will probably claim that the prediction is a marvelous product of his own mental activity.

It seems that it is impossible to prove to Berkeley that I exist. But I will be entitled the right to reject his doctrine, since I have no doubt that I exist. Ironically, my conviction about my existence is based on the same formula: cogito!

2. Berkeley, while trying to avoid the materialistic relativism (which he calls skepticism), he ends up with perceptual relativism. Therefore, his denial of external world does not provide him with certainty. According to his doctrine, all sensible qualities depend on personal perspective. Thus, the idea of God as casual notion is the result of Berkeley’s personal perception, which does not warrant the independent existence of the perceived (God).

However, Berkeley never claims that he perceives God. On the contrary, he acknowledges that he has no idea of God or any other spirit. It is incredible, then, to understand why he denies the existence of physical world despite his numerous perceptions about it, and accepts the existence of God even without any ideas having about him? His defense, by creating “notions” besides his key word “ideas” is not satisfactory.

3. Berkeley’s argument on the relation between heat and pleasure-pain is not “very ingenious” as claimed by W. T. Jones (J. 283, lll). He argues that any “material substance” which contains heat cannot perceive its own heat, since it is senseless. Heat can only be perceived by us. Thus, he tries to isolate this and all other sensory properties from the “matter”, which ultimately reduces it to an empty concept. Here is the problem with his argument: First, contrary to his assertion, matter can perceive the heat. For instance, water shows its perception by freezing and boiling activities. Metal expands or shrink. However, there is a difference between our expression of perception: while water reacts to heat by boiling we react by screaming. Second, Berkeley cannot prove that water is senseless, that is, not aware of its perception of fire.

Berkeley seems senseless towards the countless “perceiving” objects around him. Thus, he creates the notion of Divine Spirit in order to cover his insensitivity.