In contrast to science, which depends for its advancement upon the gradual temporal development of the technology of instrumentation, philosophy depends upon common human experience had by all throughout the ages.
St. Thomas presents five ways of proving the existence of God in the Summa Theologica, Q2, Article 3. He writes within the tradition of western philosophy, which recognizes the true, the good and the existent as only logically, not really, distinct. His five ways are logical perspectives of one argument, the singular conclusion of which is that there is a being whose nature and act of existing are identical. That Being, beyond our experience, must exist, in order to explain the existence of those beings which we do experience.
Western philosophy is based on two principles. The first is: Things exist. The second can be expressed in many ways. Examples: Everything makes sense; Everything has an explanation; Things are intelligible.
The essential argument for the existence of God is that everything within our experience is limited in existence because it is explicable by its nature up to a point. Its nature explains its being in act, except for its very act of existence. There must be a being, beyond our experience, which does not have this fatal flaw. Its nature must be to exist, thereby explaining its own existence and the existence of the things within our experience.
St. Thomas’ five ways are:
1) Motion: At the level of existence, there is motion from potentiality to actuality of the things within our experience.
2) The nature of the efficient cause: Nothing in our experience is the efficient cause of its own existence.
3) From possibility and necessity: The things we know are merely possible and as such are indifferent to existence.
4) There is gradation in the true and the good within our experience.
5) There is governance or purposefulness in things, even in inanimate things. Things move with purpose, i.e. toward the good. Purpose requires intelligence, which is lacking as a power in inanimate things even though they are intelligible.
The first three ways refer directly to existence; the fourth refers to existence via the true and the good; the fifth refers to existence via the good and the true under the aspect of purpose.
Recently, there are said to be new proofs of the existence of God. One of these is the argument that, because of the existence of conditioned realities within our experience, there must exist at least one unconditioned reality in all of reality (i.e., a reality that does not depend on conditions being fulfilled in order to exist but exists in and through itself).
Is this a new and valid argument?
The first of the five ways above argues there must be an entity of pure act because the entities within our experience contain potency.
If conditioned means having potency to exist, then the argument is not new.
If conditioned means not being the efficient cause of its existence, then the proof is not new.
If conditioned means contingent on another for its existence, then the proof is not new.
If conditioned means not explaining within itself its own degree of goodness and truth, then the proof is not new.
If conditioned means not being its own purpose of its existence, then the proof is not new.
What does conditioned mean? Its meaning can be inferred from the cited examples of conditionality. Among these are: A cat is a conditioned reality because it is dependent upon the cells of its body in order to exist. A mammalian cell is a conditioned reality because it depends upon its proteins in order to exist. A protein molecule is a conditioned reality because it depends upon amino acids in order to exist. It would seem that being composed of parts is what is meant by conditioned, but this understanding is unsatisfactory.
Having parts is not an adequate meaning of conditioned in the context of a new proof of the existence of God, because:
If having parts implies having potency to exist, the argument is not new.
If having parts implies not being the efficient cause of its own existence, the argument is not new.
If having parts implies not being contingent in its existence, the argument is not new.
If having parts implies not explaining its own degree of goodness and truth, the argument is not new.
If having parts implies not being its own purpose of existence, the argument is not new.
The primary reason that the argument from the conditioned to the unconditioned is invalid, though new in the specific conditions it cites, is that the relationship of the conditioned to the unconditioned relates to form, not to existence. Even the fact of having parts alludes to form, not existence.
This cat is this individual cat because of its particulars, its conditions. These conditions are its obvious properties such as its size and color, but also all of its more subtle properties, such as its cells and their protein and DNA complements.
The unconditioned cat is the abstract, universal cat, which is not specified by a myriad of conditions, but as an abstract, logical universal comprises all such conditions including all the conditions of this house cat and that lion. The conditions are the particular properties of this cat as the composite of matter and form.
The conditioned cat (or conditioned reality) does indeed require the unconditional, universal, abstract form of cat (or unconditional form), which does not exist in itself as does this cat. The unconditioned, i.e. the universal form persists as a fully valid and unchangeable concept, even if all real, particular cats should become extinct.
The fact that a conditioned form really exists in this conditioned reality (such as this cat) does indeed imply the unconditioned, universal form, both as a principle in this cat and as a concept in logic. However, this is no proof of the real, actual existence of the universal form in itself, let alone the existence of God.
Even in the logic of mathematics, the conditioned form presupposes the unconditioned form. For example a triangle, as conditioned, may have three equal angles and a side length of 10 units. As conditioned, another may be an isosceles, right triangle with a hypotenuse having a length of 4 units. The unconditioned form, which is a three-sided polygon, includes both of these conditioned triangles and all other conditioned triangles. The unconditioned form is logical, just as the conditioned triangles are logical. With respect, both to logical concepts and to material entities, the relationship of the conditioned to the unconditioned is a relationship of form not of existence.
We do not experience reality as conditioned reality. We experience entities by means of their conditions, i.e. the particulars of their forms. We experience entities as conditioned in form, not as conditioned in existence. It takes the old arguments to recognize that the unconditioned form of an entity explains the conditions of its form, but not its existence.
If the argument from the conditioned to the unconditioned is valid, it is not new. If it is new, it is of relationships within form, not relationships within existence and, therefore, not valid.