The task I have determined to undertake here is a formidable one. Despite this, I am excited about adding in some key works of David Lewis. From Amazon:
David Lewis (1941- 2001) was Professor of Philosophy at Princeton University. His publications include Convention (reissued by Blackwell 2002), Counterfactuals (reissued by Blackwell 2000), Parts of Classes (1991), and of numerous articles in metaphysics and other areas.
The books I plan on reading are On the Plurality of Worlds and Counterfactuals. Here is the description of former:
This book is a defense of modal realism; the thesis that our world is but one of a plurality of worlds, and that the individuals that inhabit our world are only a few out of all the inhabitants of all the worlds. Lewis argues that the philosophical utility of modal realism is a good reason for believing that it is true.
After putting forward the type of modal realism he favors, Lewis answers numerous objections that have been raised against it. These include an insistence that everything must be actual; paradoxes akin to those that confront naive set theory; arguments that modal realism leads to inductive skepticism, or to disregard for prudence and morality; and finally, sheer incredulity at a theory that disagrees so badly with common opinion. Lewis grants the weight of the last objection, but takes it to be outweighed by the benefits to systematic theory that acceptance of modal realism brings. He asks whether these same benefits might be gained more cheaply if we replace his many worlds by many merely ‘abstract’ representations; but concludes that all versions of this ‘ersatz modal realism’ are in serious trouble. In the final chapter, Lewis distinguishes various questions about trans-world identity, and argues that his ‘method of counterparts’ is preferable to alternative approaches.
Here is a description of the latter:
Counterfactuals is David Lewis’s forceful presentation of and sustained argument for a particular view about propositions which express contrary-to-fact conditionals, including his famous defense of realism about possible worlds. Since its original publication in 1973, it has become a classic of contemporary philosophy, and is essential reading for anyone interested in the logic and metaphysics of counterfactuals.
If it is not already obvious, the purpose of including these works is that they (especially the former) provide the philosophical groundwork underpinning Tegmark’s ideas. As I mentioned before, the MUH is a form of modal realism and could be described as a mathematized version of Lewis’s philosophy.
Since I am already addressing Tegmark’s ideas along with Hofstadter’s I hope to not become bogged down by adding in more, but the relevance of Lewis’s work in this matter seems justification enough to shoulder the burden. I hope everyone who reads this is as excited as I am to engage these ideas!