In my book, Why Christianity is True, in the section on arguments for the existence of God, I argue that the fact that the universe is a whole made up of a variety of parts points to the existence of God, for all the parts must find their origin in an ultimate unity. I want to make this same argument again briefly in another way.
The universe is made up of lots of parts. There are lots of individual objects, like trees, cars, people, rocks, etc. These objects are obviously parts of a larger whole. There is clearly a fabric of reality that transcends these individual objects, in which they all exist. There is a nexus, a framework, a background, or whatever you want to call it, in which all objects exist and by means of which they are able to be interrelated. In short, there is a whole in which the parts exist; and the parts are derived from this whole, as their very essences are oriented in relation to this whole and they exist only in the context of it. And yet where is this whole? What is this reality in which all things exist? This whole, this nexus, cannot be identified with any of the individual objects. And yet what else is there? Is the whole simply the collection of all the parts? This cannot be, for a collection of parts is not really a separate entity; it is the same as simply all the parts put together and is made up wholly by them. It is not a separate entity in its own right. And yet there must be some reality, distinct from the individual parts, that functions as the nexus in which those parts exist.
So in order to explain the universe we see, we need to have some reality that is the context in which all things exist and yet is not itself any of the actual individual objects that exist as parts of the whole. This framework, this nexus, must be indivisible. In classic philosophical language, it must be "simple"--possessing no parts itself. If it were divisible, if it possessed parts, then we would be back to square one and would have to go back to yet a more ultimate nexus in which those parts exist. The only possible solution is that the individual parts of the space-time universe are ultimately derived from and exist in the context of some ultimate, indivisible substance/being. And that, of course, is God (although other arguments need to be added to show why this being is conscious, etc.). Our universe only makes sense when it is seen as derived from and dependent upon a more ultimate, indivisible reality.