The way I see it, something doesn’t need to be undeniably “True” to have utility. As humans we don’t actually need to be correct about everything we encounter, just correct enough. A working understanding can be perfectly sufficient because most of us aren’t neuroscientists who study sleep. It’s okay for us to be wrong and society will forget about this book in a short time. Someone will write a more “accurate” book about sleep that’ll get popular. But in the meantime if we start paying more attention to sleep hygiene that’s good enough for me.