CAST 2011 hosted an interesting debate between Doug Hoffman and James Bach on the topic of schools of software testing. The question under discussion was not whether there are different schools of thought within the testing community or not, but rather whether naming the schools and associating people with them is a good - or really bad - idea.
The debate was energetic, and clearly provoked a strong reaction in a lot of the attendees, which was only expected. The core issue is of course if it is ok to categorize people without bothering with their opinion. Most people categorize others, but hate when they themselves are put in a category that they do not approve of, or think they should belong to. It is a very touchy subject.
Personally, I like it.
To me, the fact that someone is associated with a school of thought corresponds to me being provided with a table of contents of a book. Let me try to explain. If person A says to me "- Person B belongs to the XYZ school", it provides me with a limited amount of information about person B, just like browsing a table of contents tells me something, but not everything, about the book. Immediately - without having to read the whole book (i.e. without having to have a deep discussion with the person) - I get a rough idea of the contents (i.e. the person's views and ideas). The same way I do not mind being associated with a school, or associating myself with a school. I find it helpful because I do not have to explain my general views over and over again, I just need to state which school(s) I consider myself belonging to. Sometimes I will disagree when others associate me with a certain school, but that on the other hand gives me valuable clues as to how I am perceived. And it might even make me change my behaviour.
However, I do assume that people are mature and intelligent enough to realize that a table of contents can be misleading, and in order to get the full story you actually have to read the book. You cannot know a person without having talked to them and having formed your own opinion.
I think the concept of schools of testing is helpful, and in all honesty - even if it was rejected people would still categorize each other 'secretly'. I would rather have it done openly so you at least can have a discussion.