>The question for me is: how can we have infinite growth on a planet with limited resources?
1. Some resources are truly unlimited. We can ultimately meet all our food and energy needs via unlimited energy from the sun, for example. If necessary, the economy would adjust to do just that.
2. We aren't going to be limited to one planet forever. We'll be mining extraterrestrial objects long before we run out of stone or metal on Earth.
As for point 2: you’re underestimating the distance between stars. Trade on the interstellar scale can’t exist; so we’re limited to at most our own solar system (I would count a colony in a new solar system to be a separate system altogether).
1. Some resources are truly unlimited. We can ultimately meet all our food and energy needs via unlimited energy from the sun, for example. If necessary, the economy would adjust to do just that.
2. We aren't going to be limited to one planet forever. We'll be mining extraterrestrial objects long before we run out of stone or metal on Earth.