"Physics seems to us a promising thing to work on, and alchemy and theology obvious wastes of time." I'm not sure which "us" pg is referring to, but the essay gives me the impression that he meant something like "most people" (I could be reading him wrong, but that was my impression). Alchemy is obviously a waste of time -- I won't dispute that, and I suspect that "most people" would agree with that assertion. Being…
I'm just guessing here, but I suspect PG doesn't care what "most people" think about theology. He is probably writing from the perspective from an educated person who see the enormous influence of Newtonian physics, and see absolutely no benefit from his theological thinking. Seriously, who today even knows what Newtons theological theories were?
Alchemy as well was not so ridiculous as people seem to think. Modern hatred for alchemy seems more like a way of patting ourselves on the back and saying "We're so smart! Good thing we don't believe in that nonsense like those benighted fools hundreds of years ago." But in reality alchemy was a pre-scientific attempt at understanding the world which, if I understand correctly, merged more or less directly into what we no consider science.
It seems to me that the two things PG dismissed completely in his article are in fact the foundations upon which our modern world is largely built. There's more to the world than physics...even if physics is, in a sense, all there is.