If I use the word "Doctor" amongst laypeople, they will think I actually work as a doctor, treating people or advancing medicinal research on a daily basis.
If I use the word "Mathematician", they will think I work at a university where I spend some of my time lecturing students and some of my time doing research into complicated math problems.
If I use the word "Scientist", they will think I work in some laboratory where I am pivotal in the advancement of some cutting-edge research that will make the world a better place.
However, one can denote oneself using above terms by merely graduating and/or acquiring a PhD, even if one then left the field entirely, either out of choice or due to a failure to succeed.
My question is thus, is it wrong to call oneself a Doctor/Mathematician/Scientist if one is actually not working as one such, but merely acquired the appropiate degrees? Since clearly one is knowingly deceiving others*? If this question is too opinionated, I shall then ask: how many academics do actually use their degrees and doctorates to label themselves even if they actually are not working in those fields?
*To provide an example of such deceit, I had thought for a long time that Sam Harris, who writes many pieces on political, religious and scientific affairs, actually was a neuroscientist, as he claims. That sounded massively impressive to me the first time I heard it, and added much merit to anything he had to say about science. I recently however found out that all he has done as a "neuroscientist" is get a PhD in it, and his thesis has been heavily criticized.