The title of "Engineer" belongs to a Graduate from a University with a degree.
Well that's Brunel out for a start !
I'd say personally that the difference lies between those who just "do", and those who "think and do". A degree is one route into learning how to think and make decisions, but far from the only one. On the other hand a degree alone, certainly doesn't teach you how to "do" and a thinker alone is not yet an Engineer.
Why has this descended into yet another engineer .v. technician terminology debate?
G