Internal Problem of Evil
We now move on to the internal problem of evil. It is “internal” because the argument claims to demonstrate an inconsistency within the Christian worldview. Given the attributes of God taught in Christianity, it is not possible for both God and evil to exist. It is also called the logical problem of evil because it is structured as a deductive argument. A deductive argument is where two or more premises support a conclusion. Consider the following example:
(1) All men are mortal.
(2) Socrates is a man.
(3) Socrates is mortal. (conclusion)
In order to be valid, a deductive argument has two features. First, the premises must support the conclusion. The conclusion is said to follow from the premises. Second, the premises must be true. If these two conditions are met, the argument has a certain kind of certainty, it is not probably true, or true most of the time, it is always true.
J.L. Mackie originally put the specific form of the argument we will consider in 1955.  The argument begins with the following four premises.
(1) God exists and is wholly good, all-powerful and all-knowing.
(2) Evil exists.
(3) There are no limits to what an all-powerful, all-knowing being can do.
(4) A good being always prevents evil as far as it can.
Mackie offered premises (3) and (4) as “quasi-logical rules” to connect the concepts describing God found in premise (1).
Now we combine these four premises to complete the argument.
(5) If (1) and (4) then God prevents all the evil He can.
(6) If (1) and (3) then God is capable of preventing all evil.
(7) If (5) and (6) then there is no evil (God prevents it).
(8) If (2) and (7) then evil exists and does not exist (contradiction).
Now let’s focus on the conclusion (8) above. There is a lot going on here. To say that (8) is a contradiction is a particular thing. Unfortunately, the term is sometimes used for any situation where two statements or propositions disagree. (8) is a contradiction because it is not possible for the statement “evil exists” to be true and false at the same time. Therefore, something must be wrong with the argument. Based on the criteria stated above for a valid deductive argument there are two possibilities. First, does the conclusion (8) follow from the premises? This seems to be the case. Second, are all the premises (1 – 4) true? This is where we can find a resolution.
Reconsidering the Premises
Let’s reconsider the premises we started with. Can or should any of them be modified? At the outset, it should be obvious we cannot modify (2). It is very difficult to deny the existence of evil. There may be a great deal of argument about which specific events or acts are evil, but everyone acknowledges that evil exists.
Turning to (1), a great deal of thought has been put into denying elements of this premise. The atheist will simply argue that the concept of God is something imaginary that cannot stand up to the reality of the world the way it really is. If God does not exist then there is no argument. It remains to be seen, however how the atheist can explain the existence of good and evil.
Among those who embrace the existence of God, there have been many arguments put forward that would modify premise (1) or the meaning of “wholly good, all-powerful and all-knowing.” An entire book could be written on this one topic alone. For my purposes I want to simply point out a couple, extremely diverse examples.
From within Christendom there are views that diminish or limit God’s knowledge of the future. Christian orthodoxy has always held that God’s omniscience includes perfect knowledge of the future. Human free will does not prevent God from knowing the future choices of every person. God’s sovereignty rests this knowledge to ensure that His plan occurs in the midst of the decisions of fallen men (Genesis 45; Acts 2:22-23). This is contrasted against open theism that claims God’s knowledge of the future does not include the free choices of human beings. According to Bruce Ware, open theists define omniscience as “… God’s comprehensive knowledge of the past and present only. All of the future that is undetermined by God (which includes all future free choices and actions), since it has not happened and hence is not real, cannot be an object of knowledge. This future, they say, is logically unknowable, and as such not even God can rightly be said to know what cannot in principle be known.” One the putative “benefits” of open theism is that God did not cause evil (human freedom did) and God did not know it would happen. While this might seem to address some aspects of the problem of evil, the cost theologically and metaphysically is too grave. It would be like fumigating your house every time you saw a fly our mosquito. You may kill the annoying pest, but you can no longer live in the house.
Another example can be found in how Charles Darwin viewed nature. Darwin had been exposed to the natural theology of William Paley. As Darwin and others learned more about the myriad of insects and animals in the world and the myriad ways they fed on one another, there was a certain anthropomorphic revulsion. Darwin did not see the perfect, joyous creation described by Paley. Rather he saw nature as “red in tooth and claw.” Darwin’s theory as an explanation for the development of life was compatible with many theological and metaphysical ideas of the 19th century. For example, there were some who believed that God was diminished by direct involvement in creation. Rather a God who created a universe that did not need to intervene (either in the form of miracles or the creation of man) was believed to be a “greater God.” For Darwin and others who struggled with the “natural evil” they observed in the animal kingdom, God was not directly involved. He may have created the earth and perhaps the first life, but the insects, animals and even all the plants developed via natural selection.
I could go on, but I am not writing a book. I hope these two disparate examples give a flavor of the scope and breadth of human thought that has been applied to this question. These and other ideas are not necessarily motivated by the problem of evil but they can be used to modify premise (1).
(1) God exists and is wholly good, all-powerful and all-knowing.
Open theism, denies that God is all knowing (omniscient). The “greater God” theology that would be at home in Deism modifies God’s power to act in creation. It claims that God is limited (by choice or something else) from acting in creation. However, the answer to the logical problem of evil is not found in diminishing God. It is found in reconsidering the next two premises, which we will look at in part 4.
 For example there is Process Theism from the early 20th century. See Viney, Donald, “Process Theism”, The Stanford Encyclopedia of Philosophy (Winter 2008 Edition), Edward N. Zalta (ed.), URL = <http://plato.stanford.edu/archives/win2008/entries/process-theism/>; Bruce A. Ware, God’s Lesser Glory: The Diminished God of Open Theism (Crossway Books, 2000).