It's not even required to believe that the physical world ends, merely that the complexity becomes intractable. There are many, many systems that exhibit chaoti

It's not even required to believe that the physical world ends, merely that the complexity becomes intractable. There are many, many systems that exhibit chaotic behavior (the weather is the most famous example) and thus can't be well predicted by any science, despite being wholly physical. You don't need to invoke any (possibly controversial) idea of a non-physical world to show that science can't predict everything.