Try to look at it in this way, there are many scientific "theories" that are yet to be proven experimentally but they are accepted as long as they answer a particular problem AND none other adequately explain a problem/phenomenon. Concept of God in itself entails that it does need a creator but exists without a creator. This is a philosophical argument that explains the existence of universe while none others do.
Thats an interesting response. But I diagree that this is the ONLY answer to this paritular problem. For example, why not multiple gods or maybe this all happened by chance without any cause or creator? why stick with the concept of Allah in Islam creating the universe as the answer?