Why does evil exist? Why is there sin and pain in this world? Nadler explorers this issue by describing the views of three philosophers: Gottfried Leibniz, Nicolas Malebranche and Antoine Arnauld.
In the seventeenth century a lot of common laws of physics were discovered. As a result some changes in philosophic theories were needed: If the physical world has common laws, perhaps God created these. But do these common laws dictate the subsequent possible actions God can take?
There is no doubt that God created the best possible world. But why does it include evil? According to Leibniz the existence of simple laws are a prerequisite of a rational God that (in part) dictate the best possible world that God can create. Malebranche stays close saying a rational God wants the best possible world as long as it follows simple laws of nature: God lives by the simple laws he created himself. Arnauld says God is not rational, and puny humans can never know why He does things the way He does. God doesn't create something because it is good, but something is good because God created it, no further discussion. Malebranche and Leibniz argue that if this is the case, there is no longer a need to praise God or talk about a theodicee.
So they may not agree on the logic behind it all, but it looks like God had to compromise: to create the best possible world including simple laws of nature there was no choice but to include evil. According to Arnauld and Leibniz, creation includes evil to make the result more alluring much in the same way as music has dissonants. According to Malebranche these dissonants exist because of the simple laws that God wants to follow.
A best possible world isn't necessarily the best world for every individual: Only bad things can happen to good people or only good things to bad people. This doesn't seem very fair. Luckily, Leibniz has a solution: This will be compensated in the afterlife with eternal reward or punishment. Nice and clean and impossible to disprove!
As a full-blown atheist it is sometimes frustrating to read the very solid arguments these very wise men made about why an infinitely good being would allow evil into this world without ever questioning the fundamental issues: The presence of evil without a solid reason is prove for either 1) God not being good 2) God not being perfect or 3) God not existing at all. 1 and 2 could not be possible because it said differently in the bible and 3 was never even considered. Spinoza dared to say it: God is nature, there is no higher purpose. Using the will of God to solve an argument means to seek refuge in ignorance. However, Leibniz, Malebranche and Arnauld didn't dare to go there, they actually went at great lengths to avoid it.
It's fascinating to read the often fierce debate about God, good and evil while in the end it's simple a matter of faith. Malebranche says "I believe God acts rationally", while Arnauld says "This is not the case. God is not a human, His will and reason are one". Yeah, well, that's just like your opinion, man. We might not agree now, but this was the state of philosophy, science, politics and their interrelatedness at the end of the seventeenth century and Nadler provides us with a solid insight into this periods thinking.