Hazrat Inayat said:
Once I was at a reception at a friend’s house, and there was someone there who disputed with every guest, so that they were all tired out.

I tried to avoid him, but someone introduced us; and when he heard that I was a teacher of philosophy, he thought, “This is the person I want.” And the first thing he said was, “I do not believe in God.”

I said, “Do you not? But do you believe in the manifestation and in the beauty of this world of variety, and that there is a power behind it which produces all this?”

He said, “I believe in all that, but why should I worship a personality, why should I call him God? I believe in it but I don’t call it God.”

I said to him, “You believe that every effect has a cause, and that for all these causes there must be an original cause.  You call it cause, I call it God; it is the same. There is some officer whom you salute; some superior before whom you bow, for instance, your father or mother; some fair one whom you love and adore, for whom you have a feeling of respect; some power before which you feel helpless. How great then must that person be who has produced and controls all this, and how much more worthy of worship?”

He answered, “But I do not call that a divinity, I call it a universal power, an affinity working mechanically, harmonising all.”

When I tried to keep him to one point, he ran to another; and when I followed him there, he ran to another; until at last I ceased, thinking of the words of Shankaracharya:
All impossible things can be made possible
Save the bringing of the fool’s mind to the point of truth.