Are observers fundamental to physics, or simply byproducts of it?

Are observers central to physics, or are they more accurately framed as bystanders to and byproducts of phenomena that exist independently of consciousness? In this interview from the long-running series Closer to Truth, Bernard Carr, an emeritus professor of mathematics and astronomy at Queen Mary University of London, traverses the double-slit experiment, the fine-tuning argument and more to explore what significance, if any, first-person observation holds in the realm of fundamental physics. In his conversation with the US presenter Robert Lawrence Kuhn, he doesn’t adopt a personal stance. Instead, he considers these persistent questions through a contemporary frame, assessing how discussions around them have evolved and where they stand among physicists today.