PSA: This is not a quote from C.S. Lewis. People need to stop attributing it to him, if only for the sake of my sanity.
The quote is from A Canticle for Leibowitz, written by Walter M. Miller, Jr. The original quote is:
You don’t have a soul… . You are a soul. You have a body, temporarily.
Aside from the theological issues this raises (Christian theology has been pretty clear on the issue of having resurrected bodies, so our bodies are not temporary), this quote is wrongly attributed all over the internet. This is the second time in two days I have corrected the misattribution.
One day I’m going to write a master post about this and just direct people to it.