When defining God we don't need to define every aspect of him, just as with anything in the physical universe we only need to define a few aspects to distinguish them from other things. There is always a potentially infinite number of details beyond our grasp with anything we define. We might not even have enough senses to grasp details of things that could be unveiled if, say, you had more color receptors or senses entirely.
Please keep in mind that this is an attempt at a definition, and not a philosophical argument for him. That can be made elsewhere. The big question so far is, now that we get that God can be defined as an eternal spiritual creator-sustainer being, how do we get a picture of this in our minds? And the answer: we can't, not literally. So how do we get a picture of him in our minds metaphorically?
And here I think it's not really needed to get a picture of him "as a whole". To define God might mean to grasp a few of his qualities, like eternal creator, or sustainer, or whatever. But I think it's possible to get a picture of him, such as a sphere in relation to a plane (the universe), which captures the idea that he's beyond this universe while still relating to it. Actually, the most useful image I have for him is like some grand infinity that "surrounds" (note the quotes) the universe, which is a bit like an organism that's growing or expanding inside him (the universe as its continues its spatial and physical expansion). Which brings up a cool idea of God as a mother in that he enwombs the universe.
There are other images, of course, but those are my preferred ones. Thoughts?
When defining God it is important to realize that man has a natural revelation of God, God's glory reflected in nature:
The wrath of God is being revealed from heaven against all the godlessness and wickedness of people, who suppress the truth by their wickedness, since what may be known about God is plain to them, because God has made it plain to them. For since the creation of the world God’s invisible qualities—his eternal power and divine nature—have been clearly seen, being understood from what has been made, so that people are without excuse. (Romans 1:18-20)
In my many debates with atheists I've found it interesting that they very seldom, if ever, ask for a definition of God. You would think with no evidence or the evidence is found to be insubstantial the thought would occur to them that the word for God has an inherent meaning.
Anyway, God is defined from time to time in Christian theology. Usually they will come up with a four part definition as a doctrine (or lesson).
Attributes or Properties of God:
1. Independence or aseity of God. God is separate from his creation, which by the way is the literal meaning of 'holiness', it's the idea of separation. God is altogether other and in no way dependent on any source, in fact, the term source cannot be applied to God. That's where the Aristotelian concept of God being primary source comes from, God is the prime mover, the uncaused cause so to speak.
2. Immutability of God. God is unchanging, true and faithful.
Immutability (
ametathetos): Occurs in Hebrews 6:17, 18 of the unchangeableness of the Divine counsel. It is the perfection of Yahweh that He changes not in character, will, purpose, aim (Malachi 3:6; so of Christ, Hebrews 13:8). (International Standard Bible Encyclopedia)
You see something like this in natural science, some laws of nature like gravity are regarded as immutable because the dynamics do not change. On the flip side virtually all natural laws lack immutability because our understanding of them is limited, we can be in error and it seems there are always exceptions.
3. Infinity: God is without beginning or end (Psalm 90:2; 2 Peter 3:8), God transcends time and space, God is neither included in space nor absent from it. (1 Kings 8:27; Acts 17:27)
4. Unity (Simplicity): This doctrine is a little hard to grasp but the idea is that God's essential nature is uniform. This is probably as good a description of the concept your going to get.
The being of God is identical to the "attributes" of God. In other words, such characteristics as omnipresence, goodness, truth, eternity, etc. are identical to God's being, not qualities that make up that being, nor abstract entities inhering in God as in a substance. (
Divine Simplicity)
Biblical definitions are a little harder to nail down then a doctrinal statement about God. The reason is that God is described but not really defined in Scripture because it's always assumed God's 'his eternal power and divine nature' are 'clearly seen'. Arguments for the existence of God can be found nowhere in Scripture for the same reason. In other words God is self existing and self evident, if I define God for you I'm defining something less then God. Theologians sometimes refer to this as natural revelation.
When I think of this subject I remember Socrates refusing to define 'good' in the Republic, he opted instead for a simile which is probably the best part of the dialogue for me. Mind you, Plato isn't talking about an adjective but for him the 'Good' was the highest ideal or form, not something that is good but goodness itself.
A bit on the theological side but definitions for God do exist, it just takes some time to boil them down to a substantive semantic definition that is complete and still comprehensive.
Grace and peace,
Mark