The Fine-Tuning Conjecture

Abstract

The aim of this chapter is to propose a scientific approach to finding out whether or not our universe is fine-tuned. The first difficulty is to define fine-tuning, which requires three steps: first, to debunk common and uncommon fine-tuning fallacies, which constantly sneak into the debate (Sect. 6.1); second, to distinguish fine-tuning from the closely related issues of free parameters, metaphysical issues, anthropic principles, observational selection effect s, teleology, and theology (Sect. 6.2); and third, to provide a fallacy-free definition of fine-tuning (Sect. 6.3). We propose that computer simulations are needed to address two key cosmological issues: first, the robustness of the emergence of complexity, which boils down to ask: What would remain the same if the tape of the universe were replayed? The second issue is fine-tuning, which requires us to consider the question: Are complex universes rare or common in the space of possible universes? We first discuss definitions of possible universes and of possible cosmic outcomes—such as atoms, stars, life, or intelligence. This leads us to introduce a generalized Drake-like equation, the cosmic evolution equation. This is a modular and conceptual framework to define research agendas in computational cosmology. We then outline some studies of alternative complex universes. Such studies are still in their infancy, and they can be fruitfully developed within a new research field supported by computer simulations: artificial cosmogenesis. Thanks to those new conceptual distinctions, I critically outline classical explanations of fine-tuning: skepticism, necessity, fecundity, God of the gap s, chance of the gaps, WAP of the gaps, multiverse, and design (Sect. 6.4). In Chap. 7, we shall underscore the importance of artificial cosmogenesis by extrapolating the future of scientific simulations, and in Chap. 8 we shall examine two additional evolutionary approaches to fine-tuning.