Omnipotence literally means the ability to do all things, or to have absolute power. This quality seems to be generally accepted as an intrinsic characteristic of the Judaeo-Christian god, as it says in Luke I. 37, "...there is nothing that God cannot do.". Certain objections can be raised to attributing this characteristic to god however, in-so-far as this characteristic seems to conflict with other accepted attributes of god. In The Summa Theologica St. Thomas Aquinas addresses some of these objections, the most telling of which can be restated as:
(I) To sin is an action, however god is unable to sin. Therefore god cannot be omnipotent.
(ii) The greatest act possible of god is his practice of "sparing and having mercy". There are actions judged to be much greater however, such as creating a world. Therefore god is not omnipotent.
(iii) If god is omnipotent, then everything is possible and nothing is impossible. If this is true however, things which are necessary (things which cannot possibly not exist) are no longer so. This is impossible - therefore god cannot be omnipotent.
Aquinas begins his rebuttals by defining what is encompassed by the characteristic of divine omnipotence. He explains that god is able to all things which are "possible absolutely", which he defines as all things which can be logically expressed without the predicate being in conflict with the subject - i.e. god is capable of all things which do not involve a contradiction in terms. This does not imply any defect in the power of god, Aquinas goes on to say, because impossible things by definition have "no aspect of possibility", moreover, it is absurd to expect divine omnipotence to encompass the logically impossible.
(I) Aquinas answers the first objection as follows. He explains that "...to sin is to fall short of perfect action; hence to be able to sin is to be able to fall short in action..." which he attests is contrary to...