Is a question atheists often pose to counter a theist’s argument that a creator God is likely because of the universe’s complexity and appearance of design.
The question, “if God made the universe, who made God?” contains a category error:
A category error occurs when someone acts as though some object had properties which it does not or cannot have. The reason why it cannot have those properties is because the properties belong to objects in some other category or class. For example:
Colorless green ideas sleep furiously.
The above sentence commits at least two category errors. One is the attribution of the property of color (green) to something immaterial (ideas). This is an example of a property (color) which “ideas” cannot have. A second is the attribution of a property of speed/manner (furiously) to an action (sleep). This is an example of a specific property which sleep does not have, even though sleep can have other, similar properties – like soundly or quickly.
God, by definition, is in the category of things that are not created.
The universe began at the big bang; before the big bang it did not exist. It is in the category of things that are created.
To ask “who made God?” can only make sense if it is asked about a created god, not about the uncreated eternal Christian God.
So, for an atheist to ask, “if God made the universe, who made God?” in order to try and weaken the argument for God from design is illogical.