2018-08-22
10:15 at HCP F 43.4

How to infer a multiverse from fine-tuning for life - if at all

Simon Friederich

University College Groningen, Groningen, The Netherlands

Many aspects of the laws and constants of nature are claimed to be fine-tuned for life. The argument from fine-tuning for a multiverse infers from These instances of fine-tuning that there are likely many other universe with different laws and constants. This argument is sometimes characterized as an inference to the multiverse as an anthropic explanation of fine-tuning for life. I argue that, whether or not the argument is sound, this characterization is inadequate. A paradigmatic anthropic 'explanation' is Robert Dicke's (1961) account of coincidences between large numbers in cosmology. But there is a crucial difference between Dicke's account and the argument from fine-tuning for the multiverse: whereas Dicke uses life's existence as background knowledge based on which he accounts for the observed coincidences, the argument from fine-tuning for the multiverse treats life's existence as what needs an explanation (rather than as background knowledge).

Having established this observation I argue that it may indeed be rational to increase one's degree of belief in the multiverse when confronted with fine-tuning for life - but not because the multiverse can explain why we exist despite the required fine-tuning.