Temperature increases one degree for every seventy feet you descend into the earth. And the pressure on its own is enough to melt rock. No living thing could survive!

Uncle reminds me that these are just theories, and the scientific method is to test theories. "Follow Saknussemm's example: go and see!"
Should I remind him of a dozen other reasons why this would be fatal? Or just follow him to our deaths? Or do something else?