are sometimes considered formal
when they have developed a set of axioms
which can be described with a certain "magic" amount of completeness and rigor. Mathematics
is widely given as an example of formality. Others have postulated that any process which can be conducted by a machine
should qualify as "formal" (incidentally, this excludes
mathematics as a whole from formality).
The key danger in formality is in perceiving it as a yes or no proposition, when, in fact, it is always an unbounded continuum.