The logical problem of evil was most famously expressed by David Hume when he wrote “Is [God] willing to prevent evil, but not able? then is he impotent. Is he able, but not willing? then is he malevolent…”  The existence of evil seems to demonstrate that Christian faith rests on what Hume called “an inconsistent triad” of beliefs, namely that God exists and is omnipotent, God exists and is omnibenevolent and that Evil exists.  While writing many centuries before Hume, St Augustine repeatedly responded to this same problem and developed a complex, multi-layered theodicy.  While St. Augustine is best remembered for his free will defence, he also proposed that evil is a lack of good (privatio boni) and so not a positive part of God’s creation and reasoned that God allowing there to be privations of good is justified with reference to the principle of plenitude, in that they facilitate diversity in nature which is awe-inspiring and beautiful, pointing to the glory of God and the need to worship Him. Nevertheless, and despite the sophistication and importance of St. Augustine’s attempt to resolve the logical problem of evil, his attempt was not successful.

Focussing first on the free-will defence argument, St Augustine argued that evil results from the human misuse of free-will and is therefore our fault, not God’s.  God, being omnibenevolent, is beholden to create the best possible world and this, St Augustine reasons, contains free beings who can choose the good, rather than achieving it by design.  However, the freedom to choose the good necessarily entails the freedom to choose to sin, causing suffering to ourselves, other people and indeed the whole of creation as God, again being omnibenevolent and so just, is beholden to ensure that evil actions have evil results in order to deter people from choosing them again.  When human beings chose to sin, first corporately at the Fall in Genesis 3 in which all humanity was “seminally present” in Adam, and then as individuals, evil and suffering entered the world not by God’s design, but as a logically necessary consequence of God creating the best possible world. This argument is fraught with difficulties however.  Firstly, as JL Mackie asked in his famous essay “Evil and Omnipotence”, why could not an omnipotent God create a world containing free beings who always chose to do what is right?  Omnipotence suggests that ability to do anything, even (as Descartes reasoned) what seems logically impossible to us, such as making 2+2=5.  Secondly, even if (as St Thomas Aquinas argued) God’s creative action is timelessly simple and cannot, therefore, contain logical contradictions, why shouldn’t an omnipotent God create free beings whose poor choices have less severe consequences than they do in our world.  Is the holocaust a logically necessary consequence of God’s creation of the best possible world?  If it is, the meaning of omnipotence – and of best in the context of possible worlds – seems to be very far indeed from any meaning we can understand. Thirdly, such omnipotence and such a “best” possible world seems incompatible with God’s omnibenevolence; wouldn’t a good God have been better not to create at all than to have created a world in which the holocaust (and perhaps even worse examples of human depravity yet to come) was a logically necessary feature. Fourthly and finally, the whole idea of human beings having free will is inconsistent with the notion of divine omnipotence.  Ass Boethius acknowledged in the Consolations of Philosophy Book V, Omnipotence is usually understood to entail omniscience and, if God knows what we will choose before we choose it, our freedom is not meaningful.  Given that God has both the power to step in to prevent the consequences of our poor choices and the goodness that demands that he should, divine omniscience negates the free-will defence and means that this aspect of St. Augustine’s attempt to resolve the logical problem of evil is unsuccessful.

Moving on to consider St. Augustine’s suggestion that evil is “privatio boni” and therefore not a part of God’s creation for Him to be responsible for.  While defining evil as a privation has been popular through the history of the Church with Philosophers – St Thomas Aquinas also defined evil in this way – as John Hick pointed out, it is deeply unconvincing in a pastoral context.  To those afflicted by suffering saying that child cancer is not a positive part of God’s creation but only results from a justified instance of a lack of good things seems deeply inappropriate as well as being unconvincing.  Medicine has moved on since the 5^th Century and we now know that much sickness is not caused by a lack of health but by pathogens which have a very real existence.  Why did an all-powerful, all-good God create coronaviruses, whose only purpose seems to be to infect beings in order to multiply themselves, whatever suffering that causes?  The standard response to this, pointing out that we are criticising God’s creation on the basis of our own perspective, not God’s, falls foul of the central Christian belief that God created the natural world for human beings.  If aspects of creation make it impossible for human beings to do as God commanded, “be fruitful and increase in number, fill the earth and subdue it…” (Genesis 1:28) then this demands an explanation.  If God, being omnipotent and willing human beings to be good, created a world in which the conflicting purposes of organisms naturally and inevitably results in suffering then there is indeed a logical problem.  It is simply not possible to deny the existence of evil or reduce it to a lack of good when “nature is red in tooth and claw”.  In this respect as well, therefore, St. Augustine’s attempt to resolve the logical problem of evil is unsuccessful.

Moving on to St. Augustine’s claim that God allowing evil and the suffering it causes is justified with reference to the Principle of Plenitude, this aspect of his Theodicy is also unsuccessful.  St. Augustine claimed that God is justified in creating, even when creation necessarily involved privations (evil), each of which would cause intense suffering, because of the beauty of creation, which would point towards and express God’s own glory.  For St. Augustine, part of God’s goodness is the need to express his nature creatively, yet this implies a limitation on God.  If God is omnipotent, then why should God have the need to express his nature creatively… and even more so if that creative self-expression would inevitably lead to privations on the scale of the holocaust.  St Augustine also reasons that God’s creative self-expression, including its necessary privations, is justified because it points the human mind to the existence and glory of God.  Yet again, this implies that God has a need to be known, acknowledged, worshipped and glorified in a way that seems to undermine His omnipotence.  If God is omnipotent He must also be omniscient which, as St. Thomas Aquinas argues in Summa Theologica 1,14,2, includes having perfect self-knowledge such as that “God understands Himself through Himself”. If God knows himself perfectly, then why would he have any need to be known, acknowledged, worshipped and glorified by any created being?  In this respect as well, therefore, St. Augustine’s attempt to resolve the logical problem of evil is unsuccessful.

Of course, St Augustine’s theodicy has been enormously influential.  Today Alvin Plantinga’s “God, Freedom and Evil” draws heavily on all aspects of the Augustinian tradition to provide a way for believers to defend themselves against the “defeaters” levelled at faith by atheists.  Plantinga has adapted Augustine’s arguments to address common criticisms, such as by developing his argument for transworld depravity to show that suffering will result from God’s creation of free beings in any possible world without ever having to be part of God’s intention for any world. Nevertheless, despite the continued popularity of the Augustinian-type theodicy, it remains deeply problematic.  Plantinga’s argument still depends on God being both omnipotent and having to create free beings the consequences of whose actions cannot be limited.  He still reasons that God can be both omnipotent and omniscient and not be responsible for the consequences of human choices. He does not so much defeat Mackie’s criticisms of the Augustinian theodicy as deny them. 

In conclusion, St Augustine’s attempt to resolve the logical problem of evil is unsuccessful at every level.  His free will defence fails to reconcile God’s omnipotence with His omnibenevolence, his re-definition of evil as privatio boni fails to do justice to the real experience of evil and its effects in the world and his Principle of Plenitude implies that God, being omnipotent, is still limited.  Despite the fact that St. Augustine’s theodicy continues to inspire writers like Alvin Plantinga, philosophers of religion should look elsewhere if they want to make progress towards a resolution of the logical problem of evil.