Developments in both cosmology and particle physics suggest that our universe may just be one member of an ensemble of universes, termed the multiverse. Since the values of the physical constants may vary across the ensemble, this could provide a scientific basis for the suggestion that some of them are fine-tuned for the existence of observers. The evidence for this comes from numerous unexplained ‘coincidences’ between the constants, a notion which used to regarded as purely philosophical or even theological. But what is the universe fine-tuned for? Is it for complexity or some physical feature (such as the existence of black holes) or is it tuned for life or consciousness. And is the multiverse a proper scientific proposal or just philosophical speculation? It will be argued that the multiverse suggests that mind is a fundamental rather than incidental feature of the universe and that the nature of science must expand to accommodate this.