With the release of the wonderful AJP volume in honour of David Lewis, it is worth pausing to consider the future of Lewisian philosophy. Others who know enough about history that they aren’t doomed to repeat it might be able to say something serious here about how Lewis’s immediate legacy will compare to other greats. For better or worse, that’s not what I can do with any plausibility. But implausibility has never stopped me before.

So let’s start with a simple induction. Many intellectual giants suffer the indignity of having doctrines named after them that they never endorsed. This leads latter day scholars to come along asking “Was X an X-ian”. This question has been asked about Hume, Marx and Keynes, amongst others I’m sure. By induction, the same thing will happen to Lewis eventually. It’s just a matter of when. So here’s the first question.

bq. How long until the first “Was Lewis a Lewisian” paper?

I’m putting the over/under line at 2015, and taking the under. (If only because I can write the paper in 2014 if no one else does.)

You might be tempted to think that no such paper could be written, because Lewis’s writing is so clear that no one could attribute meanings to him that he didn’t actually endorse. The argument form here is historically dubious. Russell too was a clear writer, but compare Russell’s theory of “Russell” with the Russellian theory of “Russell”. Yet I come not to question the validity of this argument, but rather its soundness.

Lewis appeared to write clear, transparent philosophical prose. But it is clear to those with eyes to see it, that many layers of meaning lay hidden beneath those welcoming texts.

For instance, the folk take Lewis’s masterpiece On the Plurality of Worlds to be an argument for the plurality of worlds. And this clearly is the exoteric meaning of Lewis’s text. But could a thinker of Lewis’s quality really have believed in this metaphysical monstrosity? It is hard to credit. The real meaning must lay deeper.

For a long time I thought that the book was obviously an argument for the existence of God. Lewis conspicuously fails to discuss theological ersatzism – the view that ersatz possible worlds are really constituents of the mind of God. Given the devastating attacks Lewis launches on rival theories, and the utter implausibility of Lewis’s preferred alternative, I thought the esoteric message was clear. Philosophy needs a theory of modality. Theological ersatzism is the only viable theory of modality, the others being disposed of in Lewis’s book. Theological ersatzism needs God. Hence God exists. A fittingly impressive argument for a great thinker’s masterpiece.

But, and let this be a lesson in how intricate Lewis’s texts can be, I too had been deceived. The clue I missed was from the paper Putnam’s Paradox. Lewis ever so clearly lays out Putnam’s ‘paradoxical’ argument for anti-realism. And then, in his customary fashion, provides a solution so outlandish that the trained scholar is clearly meant to reject it. He even acknowledges that the solution bears the trademarks of medieval scholastic corruption of Greek thought.

This paper poses a puzzle though. Why, if Lewis thought Putnam’s argument was sound, is he so hostile to Putnam in the paper? Returning to Plurality makes everything clear. As the title of Part 2, “Paradox in Paradise…” indicates, Lewis thinks the paradox spreads throughout paradise, and infects all talk related to modality. And as he says in Part 1, ever so slyly using the literal voice, this covers all manner of things philosophers care to think about. Putnam’s error, Lewis is saying, was to not see how far his anti-realist argument spreads. Plurality, when read in light of Putnam’s Paradox argues for anti-realism about modality, and hence for all of metaphysics.

This clearly rebounds on the theological argument above. For if God exists, then theological ersatzism is true, and hence a (reductive) realism about modality is correct. But we should be anti-realists about modality, so we must be anti-realists about theology.

That line of reasoning seemed compelling, but it was delicate enough that I would have expected Lewis to offer some kind of confirmation that it was correct. And he does in Evil for Freedom’s Sake. There he argues that the various realist positions on God, classical theism and atheism, are reduced to an indecorous squabble over burdens of proof. The clear message is that the Putnamian anti-realism he defended in Putnam’s Paradox and expanded upon in Plurality should be extended to theology.

As I have been deceived before about the meanings of Lewis’s texts, I fear there may yet be much more meaning meandering beneath the meniscus. Anyone who can come up with a better explanation is more than encouraged, nay is entreated, to do so.

This post owes a lot to Brad DeLong’s work on Strauss, which taught me everything I know about textual interpretation. Thanks also to Michael Glanzburg for some helpful suggestions.