• The claim that there is more than one god is logically invalid
Islamic theology scholars mentioned various evidence in order to prove the oneness of Allah. The most important of them is the evidence called reductio ad impossible that refutes the claim that there is more than one god.
When we assume that there are two equal gods in the universe, it is definite that there will be discussions between them and conflicts between their wishes.
In the end of such a conflict, for instance, when one god wanted something to happen and the other wanted it not to happen, one of the following three possibilities would happen.
1. Both of the gods’ wishes would take place.
2. Neither of the gods’ wishes would take place.
3. One of the gods’ wish would take place and the other’s wish would not.
All of those possibilities are rationally invalid and impossible.
If the wishes of both of them took place, a state in which something would happen and would not happen at the same time would take place, that is, two opposites like existence and non-existence would come together, which is logically impossible.
If neither of the gods’ wishes would take place, it would mean something would be deprived of existence and non-existence, that is, the opposites would disappear, which is also rationally and logically impossible.
In addition, the gods would suffer weakness when their wishes were not realized. Weak beings cannot be divine beings; they cannot create anything.
In the third possibility, the wish of one of the gods would take place and the other would be prevented; then the god whose wish did not take place would become weak. A weak being cannot be a god.
Moreover, we mentioned that the gods would be equal; when one of them turned out to be weak, the other would be weak too because they were equal. Then, both of them would be weak. Weak beings cannot be gods.
Thus, all of the possibilities turned out to be invalid; and the theory that there are two or more gods is proved to be invalid spontaneously.
Then, the divine being that created the world is one. And that being is Allah, the Exalted, who has absolute perfection, power and greatness as a necessity of the existence of His pre-eternal and post-eternal personality.
There is other evidence that proves the belief in one God.