Wikipedia makes the following assumptions at http://en.wikipedia.org/wiki/Existence.
Ontology is the philosophical study of the nature of being, existence or reality in general, as well as of the basic categories of being and their relations. Traditionally listed as a part of the major branch of philosophy known as metaphysics, ontology deals with questions concerning what entities exist or can be said to exist (for instance: “Does UDFj-39546284 exist?”), and how such entities can be grouped, related within a hierarchy, and subdivided according to similarities and differences. A lively debate continues about the existence of God.
Epistemology studies criteria of truth, defining “primary truths” inherently accepted in the investigation of knowledge. The first is existence. It is inherent in every analysis. Its self-evident, a priori nature cannot be consistently doubted, since a person objecting to existence according to some standard of proof must implicitly accept the standard’s existence as a premise.
Life is a characteristic that distinguishes objects that have self-sustaining biological processes from those that do not—either because such functions have ceased (death), or else because they lack such functions and are classified as “inanimate“.
This brings up the following thoughts: “What does it mean to say we exist as a being?” As stated above Materialism believes the only thing that exits is what we can see feel or touch. Yet we as Christians believe in the unseen. Paul the apostle believed what we could see is only temporary but what we cannot see is eternal. In the study of metaphysics Aristotle believed our being is the summation of everything we are. Just what does all that mean?
The famous mathematician Rene Descartes came up with the term, cogito ergo sum (I think therefore I am). Descartes believed that our thoughts cannot be separated from who I am. Therefore since I am able to think then I exist. Our thoughts are not something we can touch, so where does the Materialist believe our thoughts are in relation to our being?
The Bible teaches that we are both material and immaterial. The Bible uses terms such as spirit and soul to refer to the immaterial part of man. Where does the soul come into play when a discussion on being takes place? Many Christians today want to accept the theory of spontaneous generation (Theory of Evolution). Where in the amino acid-> proteins-> DNA-> chromosome-> intelligent life process did the soul come into being? At what point in the evolutionary process did the soul come into being? If the soul did not come into being until later does that mean that a chromosome by itself is not existent? Does that mean the sperm and the egg while separate does not fit the definition of being? This brings to the surface the question, “When does the soul enter the life process, at the point the egg and sperm come together to form the single cell zygote or sometime later?”
So what does it mean to exist or qualify as a being? If all these questions can be answered how do we define a being? Aristotle believed that our existence or being was actually a summation of everything we are. Can we use these beliefs to ask ourselves, “If being is everything we are then what does it mean to say God is a being?” The idea of anthropomorphism is the idea that God has used terms we as humans would understand to describe to us himself. For instance, the Bible refers to the hand of God. Yet, as far as I know, no one has ever seen the hand of God. If existence is based on those things we can see then, “What does it mean God exists?”
These are all questions I hope to answer in my doctoral studies at Columbia Evangelical Seminary.