The concept of God is central to the development of Cartesian and Spinozan philosophy. Although both philosophers employ an ontological argument for the existence and necessity of God the specific nature of God differs greatly with each account. While Descartes suggests a Judeo-Christian concept of God, Spinoza argues a more monistic deity similar to that of the Hindu tradition.

The most significant difference however, lies within the basis and structure of each argument itself. Considered from an analytical standpoint through the lens of Gotlobb Frege, Descartes' proof of God possesses both sense and reference and is therefore capable of expressing the truth. Spinoza's argument however, employs sense alone, thus rendering it neither true nor false but quite literally meaningless.

A detailed analysis of Descartes' Meditations of First Philosophy in conjunction with Spinoza's Ethics will help elucidate these claims. Before an analysis of Cartesian and Spinozan theology can occur, an understanding of each theory must first take place.

The Cartesian proof of God is outlined in Meditation Three of the Meditations. Within this work Descartes suggests a causal argument for the existence of a supreme being. This argument can be broken down as follows: 1.Everything has a cause

2.We have an idea of the infinite 3.An idea of an infinite could not be caused by a finite thing 4.God is infinite 5.Only an infinite God is adequate to cause this idea 6.God exists

An argument such as this implies a specific understanding of Causation. According to Descartes, everything from object to idea must have a determinate cause. That is, finite existence is not self-generating but rather the product of something else. The cause in question depends upon the degree of formal and objective reality it possesses. Formal reality refers to existence within this world.

For example, a tree has formal reality as an empirical object just as an idea has formal reality as a mode of thought. Objective reality refers to existence as represented via ideas. That is, an idea of a tree possesses both formal reality as a mode of thought and objective reality as a representation of a specific tree. According to Descartes, a cause must possess “at least as much formal reality as [its effect] contains objective reality.” (Descartes 16) For example, the idea of a tree must be caused by something of more formal existence within this world than objective existence via its representation.

Therefore, the idea of tree must be caused by a specific tree rather than the idea of a specific shrub. Descartes applies this reasoning to the idea of God in the argument above. Regardless of whether or not we think God actually exists we cannot deny that an idea of God is indeed within our mind. If we have an idea of God then this idea must not only have a cause but a cause with more formal reality than objective reality of the idea itself. That is, that which the idea of God is referencing must be more substantial than the finite idea of the mind. The only cause more formally real than finite existence is infinite existence.

Since the only conceivable infinite existence is that of God, Descartes' concludes that “...In creating me, [God] placed this idea within me to be like the mark of the workman imprinted on his work.” (Descartes 19) Therefore, God must necessarily exist as the infinite cause of our finite idea of Him. Once Descartes has argued the existence of God via causation he proceeds to prove God's existence via essence: 1.The concept of God is one that is infinite and perfect

2.To not exist would be an imperfection 3.Therefore God exists The general form of this argument is a testament to Descartes' understanding of an attribute. Of attributes there are only two, an Attribute and an Omni-Generic Attribute. An attribute refers to that which is necessary to the essence of a specific substance, as perfection is necessary to the essence of God.

That is, in order for God to exist it is essential that perfection and infinitude are attributed to this existence. An omni-generic attribute, refers to that which holds of any substance but does not contribute to its essence, such as existence, duration, or number. According to Descartes, to not possess this kind of attribute is a kind of privation or lack of the attribute itself. For example, if a ball is not red it lacks the color red. Therefore, if it is essential that God is both perfect and infinite then non-existence would imply that a perfect being suffers some kind of privation.

Clearly this is preposterous, for if a perfect being were to lack anything it would essentially cease to be perfect. Ergo, God exists by virtue of His perfection. Given the above arguments one can begin to understand the nature of the God Descartes is endeavoring to prove. For Descartes, God is infinite and perfect existence. God is “eternal, immutable, independent, supremely intelligent, supremely powerful, and [the creator of] everything else". (Descartes 20) Not only does God possess this nature but it is necessary that He does so.

If God is not infinite or perfect God could not exist as these attributes are essential to God's existence. Furthermore, if God is not the ultimate creator the innate idea of God we experience would cease to be innate but adventitious (externally caused) or imaginative (caused by the mind) which is again impossible given its content. Given these qualities one can draw a connection to the omniscient, eternal, creator God of Judeo-Christian interpretation. That is, Yahweh or God is responsible for the creation of all existence, Ex nihilo, or out of nothing.

The world is created as an existence separate from that of the Divine and as such exists finitely, or limited by, God's infinite existence. (Van Voorst 212) Given this parallel, one can easily understand the sense in which Descartes understands God as eternal, immutable, independent existence outside of space and time. Now that the Cartesian argument for the existence of God is understood an outline of that of Spinoza must also take place.

Spinoza presents his proof for the existence of God within the The Ethics via one precise proposition. Proposition 11 states: God, or the substance consisting of infinite attributes, of which each one expresses eternal and infinite essence, necessarily exists. (Spinoza 91) This proposition is best explained through the use of three arguments. Each argument, while unique in itself, illustrates an aspect of Spinozan philosophy contrary to that of Descartes.

The first argument supposes that God exists as it is necessary given the essence of God itself. Before one can understand this argument one must first understand what is meant by essence. For Spinoza essence is that which is necessary for something to exist. That is, it is that without which a substance ceases to be. Spinoza employs this idea of essence in a negative proof for the existence of God: 1.Consider the idea that God does not exist

2. This consideration would mean that God’s essence does not possess existence 3.This is absurd since Substance (God/Nature) necessarily exists 4.Therefore, God necessarily exists With this argument, Spinoza is suggesting that existence is an attribute of God's essence.

By attribute, Spinoza is referring to “what the intellect perceives of a substance, as constituting its essence”. (Spinoza 85) This differs slightly from Cartesian philosophy in that for Descartes existence is an omni-generic attribute and therefore does not contribute to the essence of a substance. Regardless, what Spinoza is actually saying is that we perceive existence to be essential to God. If existence is essential to God, then it is in God's nature, as substance, to exist.

Therefore, God necessarily exists. Thus, this proof not only argues the existence of God but the nature of the Spinozan substance as well, in that a substance is that of which existence is its essence. That is, “it pertains to the nature of a substance to exist”. (Spinoza 88) Spinoza's proof of the existence of God can be further represented via an argument of causation: 1.There is a cause for existence and non-existence

2.The cause of existence or non-existence is internal or external of the thing 3.If nothing can hinder the existence of a thing internally or externally then it exists necessarily 4.There is no cause internally or externally hindering God’s existence 5.Therefore, God exists