Sam Norton has started a series of post on "Reasonable Atheism", the intent being to see if the conversation between theists and atheists can be raised above that of Dawkins and company. The problem largely lies in the difference between how many atheists understand what is meant by 'God' and how many theists understand the word. The problem is compounded in that I had to use the word 'many' in both cases: the reasonable theist usually means something different from what most atheists mean, but also different from many of those who say they believe in God. Primarily, this disjunct lies in that (most) atheists think that theists believe in the existence of a being, while the reasonable theist says that God is not a being, and so the phrase "God exists" is problematic. (Note: by atheists' I am referring to secular atheists, not, say, Buddhists. Given the common usage in Western countries of the word 'atheist' as meaning someone who rejects all religion, a Buddhist might be better referred to as a 'religious non-theist' than as an atheist.)
What I want to do here is define some vocabulary that both reasonable theists and reasonable atheists can agree on. Or rather, suggest these definitions, and see what needs to be done in addition to either get to a common vocabulary, or to see where this attempt fails.
Firstly, I suggest making a distinction between the words 'real' and 'exists'. As I shall use the terms, something exists if (as its etymology suggests) it can "stand out", that is, can be an object of perception, in that it can be discerned from a background (where 'perception' is to be taken here more generally than sense perception, for example a mathematical object exists because it can be thought of, an emotion exists because it can be felt). The word 'real', on the other hand (admittedly despite its etymology) is to be taken as that which one takes into account in making decisions, in the way one lives one's life, and so forth. Needless to say, these definitions are rough around the edges, but I think they are enough to go on with.
I define God as at least the eternal (i.e., non-spatiotemporal), loving intellect that grounds all that exists. Thus, to believe in God (i.e., to be a theist) is at a minimum to claim that the ground of all that exists is to be characterized with these words (eternal, loving, intellective), while not believing in God is to claim that the ground of all that exists does not have these characteristics. And, given my distinction between 'real' and 'exists', while one runs into difficulties saying "God exists" (can something be its own ground? can the ultimate background "stand out"?), one can say without much difficulty, "God is real (or not real)".
I put in that "at least" because I recognize that many theists will demand that something more be put into that definition. In particular, the word "personal" might be thought to be required. But such objections, I think, are only relevant within the theological community. Similarly if words like 'omnipotent' are added -- additional argumentation is required to discern what is meant by such words.
On the other hand, I consider the three words used to be a minimum needed to distinguish a theist's God from, say, the God of Einstein. Also, just saying that God is "the ground of all that exists" does not make a difference that makes a difference.
Many theists may also object in that they take as given that God cannot be defined at all. To this I make two responses. The first, is that I am under no illusion that the definition I gave is final. It is only intended to provide a common ground for conversations between theists and atheists -- that is, to see if with this definition, the atheist can understand what the reasonable theist roughly means by 'God'. The second is to point out that all three words used to characterize God are themselves undefined. Again, my intention is to indicate that the difference between the theist and the atheist is in what each party considers the ground of all that exists is "like", and the three words serve as a minimum to understand roughly what is being claimed in saying that God is or is not real.
The effort that the atheist must bring to this is to understand that the words "loving" and "intellect" are being used analogically. Which is to say, we only know what these words mean insofar as they are applied to humans. Applying them to the ground of all that exists is, no doubt, problematic. And, of course, we are unable to imagine what non-spatiotemporal reality is like. But these limitations in our ability to think about God do not in themselves invalidate the possibility that God is real. They just indicate that the concept of God cannot be "thought through", which is to be expected concerning the ground of all that exists -- the same problem exists in trying to imagine a context in which a Big Bang might occur.