Should We Care about Fine-Tuning?

There is an ongoing debate over cosmological fine-tuning between those holding that design is the best explanation and those who favor a multiverse. A small group of critics has recently challenged both sides, charging that their probabilistic intuitions are unfounded. If the critics are correct, then a growing literature in both philosophy and physics lacks a mathematical foundation. In this paper, I show that just such a foundation exists. Cosmologists are now providing the kinds of measure-theoretic arguments needed to make the case for fine-tuning. 1. Introduction 2. Probability and infinite sets 2.1 No probability function 2.2 Arbitrary and wrong probability functions 3. The measure of the universe 4. The coarse-tuning objection 5. Arbitrariness and error 6. Conclusion