The Best of All Possible Worlds: A Story of Philosophers, God, and Evil (review)

Steven Nadler hopes to interest a readership wider than just professional philosophers in a largely forgotten debate he admits was not one of philosophy’s “marquee events.” It sounds like an uphill battle, even for a writer as skilled and for a historian of modern philosophy as accomplished as Nadler. Yet The Best of All Possible Worlds (henceforward BPW) succeeds in unfolding a compelling tale without distorting the fundamental doctrines of its protagonists.

And what protagonists they were, however much the passing centuries have dimmed their renown. G. W. Leibniz is still likely to have some name recognition with the target audience. But it would be unsafe to assume it for either the Oratorian Nicolas Malebranche or the Jansenist Antoine Arnauld. So Nadler weaves enough historical and biographical detail into his story, both to introduce all three and to create a background of human interest against which their philosophical differences are displayed.

The point at issue is not simple. It involves deep disagreements among the three philosophers about the nature of God, which the reader must first understand. Though not the main point, these disagreements make an indispensable conduit to what really interests Nadler: the enduring moral questions that grow out of the theological dispute, but ultimately concern the protagonists’ different views about evil.

Leibniz’s position is the best known. He thinks of God as supremely rational and good. Hence God knows every way the world could be and chooses to actualize the best of them. Ours is the best possible world, both in the metaphysical sense of being simplest in laws and richest in phenomena, and in the moral sense of being the world in which vice is punished and virtue rewarded. Still, it is not a perfect world. The challenge to understanding Leibniz consists in seeing how evil can belong to what is best.

Malebranche sees God and evil differently. Malebranche’s God, in the moment of creation, may survey the same possible worlds as Leibniz’s did, but he looks at them with different priorities. This God is looking for a world that will best reconcile his rational demand for simplicity of laws with his moral demand for a world in which Jesus Christ can successfully build his Church. God’s desire is to see his own nature mirrored in creation, and that desire may conflict with justice. There may be possible worlds in which more justice could be achieved through laws of unsightly complexity. God will not choose such worlds. He loves justice, but he loves his own rational nature more. So much so that he makes himself the sole real actor in the world; creatures only seem to act through a cunningly devised system of occasional causes.

To put their differences a little too simply: Malebranche’s God chooses a less perfect world than Leibniz’s does. But BPW’s third protagonist, the fiery Jansenist Antoine Arnauld, takes so radical a view of God that he makes Malebranche and Leibniz look like close allies. Arnauld abandons the idea of a rationalist deity in favor of one who is “beyond rationality altogether.” Our human conceptions of justice, goodness, and reasonableness have no application in evaluating the decisions of such a God. Thus Arnauld feels no obligation to explain how God can live up to our conception of justice. It is we, he thinks, who must conform our understanding to the will of God as revealed in Scripture and the Church.

A fourth philosopher, definitely not a protagonist, lurks in the background throughout and makes a cameo appearance in one chapter. He is Spinoza, one of the most reviled philosophers of his age, but also among the most carefully studied. Spinoza argued that the actual world is the only one possible, because it is, in fact, God. That being so, all that happens in it is necessary. Words like ‘good’ and ‘evil’, by which ordinary people evaluate their...