Analysis and Critique of Aquinas's Argument of Contingency

as Gilson, Aquinas hasn’t corrected the arguments of contingency given by Avicenna and Averroes, and he hasn’t even been fully aware of the differences between them. So, in the points of disagreement between them, Aquinas hasn’t entered into the discussion knowingly so that he can form a correct judgment or at least side with one of them thoughtfully.
His first argument is a combination of the arguments of Avicenna and Averroes which denotes his lack of knowledge about their philosophical principles. The same difficulty applies to his second argument according to one interpretation. Anyway, influenced by Averroes, Aquinas has drawn up his both arguments in two parts without knowing what had made Averroes to resort to that.
The use of the natural causes and effects in this argument and the application of impossibility of an infinite regress to them is also among its difficulties