Source: Man and Universe –by: Ayatollah Murtaza Mutahhari - p.88
Some people acknowledge that Allah is peerless. They recognize Him to be the only source of the world. Nevertheless, as far as His creatorship is concerned, they associate some creatures with Him. For example, some of them hold that evils have been created by some other beings, not by Allah. This kind of belief is also tantamount to the belief in the plurality of creatorship, and is diametrically opposed to the doctrine of the unity of Divine actions. Anyhow, a belief in the plurality of creatorship has several degrees. Some of them do not amount to open polytheism and as such do not put the holders of the belief concerned outside the pale of Islam.