Complex sentence: Graham Oppy, J. L. Mackie and Wes Morriston have objected to the intuitiveness of the first premise, that there is no good reason to assume "a priori" that an uncaused beginning of all things is impossible.
Split into simpler sentences: Graham Oppy, J. L. Mackie and Wes Morriston have objected to the intuitiveness of the first premise. Mackie states that there is no good reason to assume "a priori" that an uncaused beginning is impossible.