Do you believe in God? Yes?
Whoa, hold on a minute! Which God are we talking about?
Which God do you believe in?
You see, the assumption is that we all know what God is; we may differ on the details, but there's no dispute about the fundamental definition. So if you were of a philosophical bent and didn't get out much, you might say:
God is a living being, eternal, most good, so that life and duration continuous and eternal belong to God; for this is God. ... It is clear then from what has been said that there is a substance which is eternal and unmovable and separate from sensible [touchable] things. It has been shown also that this substance cannot have any magnitude, but is without parts and indivisible ... . But it has also been shown that it is impassive and unalterable
Many Christians would think that's a pretty good description of God. Trouble is that it was written by a pagan philosopher from the 4th Century BC!
Those words, from Aristotle's Metaphysics, are quoted by Mike Reeves in the first of his sensational four-part series on the Trinity, the God of the Bible. The question is whether Aristotle got it right: is his description of "God" a good summary of what the Bible's God is like?
Mike Reeves' answer: No.
We need to acknowledge straight up that the Christian worships an entirely different God to whatever God anyone else worships.