Imam al-Rida (AS) was asked the following by a man believing in dualism, ‘I believe that the creator of the world are two, so what is the proof that He is One? Imam replied, ‘Your belief that there are two is proof in itself that He is One, for verily you have only claimed the second after having affirmed the existence of the One. So the One is already a unanimous fact it is more than one that is controversial [and remains to be proven.