I guess "old in spirit" requires some definition, but one of the symptoms of getting old in spirit is the dawn of an understanding that the mind is no longer emotionally capable of reading the newspaper without degenerating into a polemic addressed to something like a household pet, or a coffee pot.
Another symptom could well be a retreat into a set of ideas that confidently
asserts that our species is actively engaged in attempting to set the necessary
conditions for a brand new and exciting Dark Age. A third symptom is deciding to
go into town without first enduring the ordeal of shaving.