This episode is focussed on the physics content of chapter 1. I explain what the current “conception” of physics is in terms of dynamical laws and initial conditions. I run through a simple example of how equations of motion are used and discuss how this has been, hitherto, the way physics has been done, is done and is expected to continue to be done according to most philosophers and physicists. We then compare this vision of physics to what constructor theory aims to achieve by considering more than just a single thread through the fabric of reality (what was, is and will be) and instead to consider what might have been and might still be. This clearly has implications for knowledge and, again, we hint at the possibility of a physics of epistemology. It also opens up the possibility for physics to address questions about why the initial conditions are the way they are and thus provides a new window into the origins of the universe and the problem of "fine tuning" when it comes to the constant of nature and the form of the physical laws.