Here's another thought - When Orual is utterly depressed about Phyche's death (as she thinks), Bardia recommends physical training. And indeed, daily physical exercise, while not lessening her grief, does enable her to overcome her inertia.
This is a great lesson in the whole spirit/body question. We are told so often that it is what's inside that counts and that our brains and hearts are what is important, that we easily discount the physical. Of course, what is inside is more important than looks or anything like that. But it is equally true that sometimes the most important thing is to just do something. Take a physical action. And there is the aspect of taking care of our physical bodies as well. How often do we focus so exclusively on inner healing that we don't even notice how the vessel that houses our inner selves is deteriorating and making the conditions for inner healing even more difficult?
And Lewis didn't even need studies about endorphins to know this.
