I'm afraid this is an extremely limited view of fuzzy logic, and is confined to
its use with numerical inputs and outputs. In fact, there are many, many uses
of fuzzy logic (and to me, the most interesting) which do not fall into this
framework.
Our knowledge is not all numeric by a long shot, and the questions we ask more
often than not do not have numerical answers. For example, in trouble shooting
we want to know what the trouble might be; we might want to know what actions
should be taken in some situation, when our knowledge is uncertain; in
diagnosis, we want to know what the possible diagnoses are with some estimate
of their likelihoods, and possibly what treatments might be most effective; in
image analysis, we might want to know what we are looking at; and so on.
In this context, we must consider not only fuzzy logic, but the whole of fuzzy
systems theory, certainly including fuzzy sets of categories, fuzzy numbers and
approximate numerical comparisons (is his age roughly 30?).
William Siler